Search Results: All Fields similar to 'Sun or Mercury or Venus or Mars or Jupiter or Saturn or Or or Uranus or Neptune or Pluto'

Solar System Montage

Title	Solar System Montage
Full Description	This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. The spacecraft responsible for these images are as follows: the Mercury image was taken by Mariner 10, the Venus image by Magellan, the Earth image by Galileo, the Mars image by Viking, and the Jupiter, Saturn, Uranus and Neptune images by Voyager. Pluto is not shown as no spacecraft has yet visited it. The inner planets (Mercury, Venus, Earth, Moon, and Mars) are roughly to scale to each other, the outer planets (Jupiter, Saturn, Uranus, and Neptune) are roughly to scale to each other. Actual diameters are given below: Sun 1,390,000 km Mercury 4,879 km Venus 12,104 km Earth 12,756 km Moon 3,475 km Mars 6,794 km Jupiter 142.984 km Saturn 120,536 km Uranus 51,118 km Neptune 49,528 km Pluto 2,390 km
Date	04/09/1999
NASA Center	Jet Propulsion Laboratory

All Planet Sizes

title	All Planet Sizes
description	This illustration shows the approximate sizes of the planets relative to each other. Outward from the Sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Jupiter's diameter is about 11 times that of the Earth's and the Sun's diameter is about 10 times Jupiter's. Pluto's diameter is slightly less than one-fifth of Earth's. The planets are not shown at the appropriate distance from the Sun. Image Credit: Lunar and Planetary Laboratory

Solar System Portrait - Views of 6 Planets

Solar System Portrait - View …

PIA00453

Sol (our sun)

Imaging Science Subsystem - …

Title	Solar System Portrait - Views of 6 Planets
Original Caption Released with Image	These six narrow-angle color images were made from the first ever 'portrait' of the solar system taken by Voyager 1, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. The spacecraft acquired a total of 60 frames for a mosaic of the solar system which shows six of the planets. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The background features in the images are artifacts resulting from the magnification. The images were taken through three color filters -- violet, blue and green -- and recombined to produce the color images. Jupiter and Saturn were resolved by the camera but Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposure times. Earth appears to be in a band of light because it coincidentally lies right in the center of the scattered light rays resulting from taking the image so close to the sun. Earth was a crescent only 0.12 pixels in size. Venus was 0.11 pixel in diameter. The planetary images were taken with the narrow-angle camera (1500 mm focal length).

Solar System Family Portrait

title	Solar System Family Portrait
description	These six narrow-angle color images were made from the first ever 'portrait' of the solar system taken by Voyager 1, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. The spacecraft acquired a total of 60 frames for a mosaic of the solar system which shows six of the planets. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The background features in the images are artifacts resulting from the magnification. The images were taken through three color filters -- violet, blue and green -- and recombined to produce the color images. Jupiter and Saturn were resolved by the camera but Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposure times. Earth appears to be in a band of light because it coincidentally lies right in the center of the scattered light rays resulting from taking the image so close to the sun. Earth was a crescent only 0.12 pixels in size. Venus was 0.11 pixel in diameter. The planetary images were taken with the narrow-angle camera (1500 mm focal length). Image Note: This 'Portrait' contains 18 frames taken through the Narrow Angle camera using the Violet, Blue, and Green Filters. The label information describes only 3 of these frames. Image Credit: NASA

Solar System Montage

Title	Solar System Montage
Description	This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. The spacecraft responsible for these images are as follows: the Mercury image was taken by Mariner 10, the Venus image by Magellan, the Earth image by Galileo, the Mars image by Viking, and the Jupiter, Saturn, Uranus and Neptune images by Voyager.
Date	02.01.1996

Eight Planets and New Solar System Designations

Eight Planets and New Solar …

Title	Eight Planets and New Solar System Designations
Explanation	How many planets are in the Solar System? This popular question now has a new formal answer according the International Astronomical Union [ http://en.wikipedia.org/wiki/International_Astronomical_Union ] (IAU): eight. Last week, the IAU voted [ http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html ] on a new definition for planet [ http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html ] and Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap010319.html ] did not make the cut. Rather, Pluto was re-classified as a dwarf planet [ http://en.wikipedia.org/wiki/Dwarf_planet ] and is considered as a prototype for a new category of trans-Neptunian objects [ http://en.wikipedia.org/wiki/Trans-Neptunian_object ]. The eight planets now recognized by the IAU are: Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap040912.html ], Venus [ http://antwrp.gsfc.nasa.gov/apod/ap040516.html ], Earth [ http://antwrp.gsfc.nasa.gov/apod/ap050102.html ], Mars [ http://antwrp.gsfc.nasa.gov/apod/ap060730.html ], Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap050911.html ], Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap041225.html ], Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap010826.html ], and Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap010821.html ]. Solar System objects now classified as dwarf planets are: Ceres [ http://antwrp.gsfc.nasa.gov/apod/ap060821.html ], Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap060624.html ], and the currently unnamed 2003 UB313 [ http://antwrp.gsfc.nasa.gov/apod/ap060207.html ]. Planets, by the new IAU definition, must be in orbit around the sun, be nearly spherical, and must have cleared the neighborhood around their orbits. The demotion of Pluto [ http://www.nineplanets.org/pluto.html ] to dwarf planet status is a source of continuing dissent [ http://www.badastronomy.com/bablog/2006/08/18/colbert-takes-neil-tyson-down/ ] and controversy [ http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20060818.063045&time=07%2006%20PDT&year=2006&public=0 ] in the astronomical community.

Solar System Portrait

Title	Solar System Portrait
Explanation	On another Valentine's Day [ http://www.poets.org/poems/poems.cfm?prmID=1166 ] (February 14, 1990), cruising four billion miles from the Sun, the Voyager 1 [ http://antwrp.gsfc.nasa.gov/apod/ap031120.html ] spacecraft looked back to make this first ever family portrait [ http://photojournal.jpl.nasa.gov/cgi-bin/ PIAGenCatalogPage.pl?PIA00451 ] of our Solar System. The complete portrait is a 60 frame mosaic [ http://nssdc.gsfc.nasa.gov/photo_gallery/ photogallery-solarsystem.html ] made from a vantage point 32 degrees above the ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap001014.html ]. Voyager's wide angle camera frames sweep through the inner Solar System (far left) linking up with gas giant Neptune, at the time the Solar System's [ http://www.seds.org/nineplanets/nineplanets/overview.html ] outermost planet (scroll right). Positions [ http://nssdc.gsfc.nasa.gov/image/planetary/solar_system/ family_diagram.jpg ] for Venus, Earth [ http://www.seds.org/billa/psc/pbd.html ], Jupiter, Saturn, Uranus, and Neptune are indicated by the corresponding letters while the Sun is the bright spot near the center of the circle of frames. The inset frames [ http://antwrp.gsfc.nasa.gov/apod/ap980517.html ] for each of the planets are from Voyager's narrow field camera. Unseen in the portrait are Mercury [ http://www.psrd.hawaii.edu/Jan97/Mercury Unveiled.html ], too close to the Sun to be detected, and Mars, unfortunately hidden by sunlight scattered in the camera's optical system. Small, faint Pluto's [ http://antwrp.gsfc.nasa.gov/apod/ap011018.html ] position was not covered.

A Sky Full Of Planets

Title	A Sky Full Of Planets
Explanation	Look up tonight [ http://www.cnn.com/TECH/9712/01/heavenly.show.ap/ ]. Just after sunset, the crescent moon and all five "naked-eye" planets (Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap971130.html ], Venus [ http://antwrp.gsfc.nasa.gov/apod/ap971014.html ], Mars [ http://antwrp.gsfc.nasa.gov/apod/ap970528.html ], Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap971030.html ], and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap970829.html ]) will be visible (depending on your latitude), lying near our solar system's ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap970927.html ]. Venus and Jupiter will shine brilliantly as the brightest "stars" in the sky, but Mercury will be near the horizon and hard to see. A pair of binoculars will also reveal Uranus and Neptune and observers with a telescope and a good site may even be able to glimpse faint Pluto just above the Western horizon in the fading twilight (not shown on the chart above). Enjoy this lovely spectacle any clear night [ http://www.skypub.com/whatsup/dec97sky.html ] through about December 8. A similar gathering is expected in May 2000 [ http://www.skypub.com/special/alignmnt/whypanic.html ] but the planets will be hidden from view by the solar glare. A night sky as full of planets as this one will occur again though ... in about 100 years.

Moons of the Solar System

title	Moons of the Solar System
description	All the planetary moons in our solar system are shown here at their correct relative size and true color. Their diversity of size and appearance is testament to the unique and fascinating geologic history that each of these bodies has undergone. Two of the moons are larger than the planet Mercury, and eight of them are larger than Pluto. Earth's Moon is the fifth largest of the set, with a diameter of 3476 kilometers (2160 miles). Most of the moons are thought to have formed from a disk of debris left over from formation of the planet they orbit. However Triton, Neptune's largest moon, and several of the smallest moons, including the moons of Mars, are thought to be captured planetesimals that formed elsewhere in the solar system. Earth's Moon is thought to have formed from the debris ejected from a roughly Mars-sized object colliding with the early Earth, perhaps a unique event in the history of the solar system. The moons are organized on the diagram by the planet they orbit (top to bottom with increasing distance from the Sun) and their position relative to the planet (left to right with increasing distance from the planet). Below is a listing of the names of all the moons and the planets they orbit. Most moons are named for mythological characters associated with the character the planet is named for. While most of the planets are named for Roman characters (with the exceptions of Pluto and Uranus), most of the moon have names from Greek mythology. For example, Phobos and Deimos are the sons of Ares, the Greek version of Mars. Jupiter?s moons are all named for lovers and other close associates of Zeus (Jupiter). Saturn?s moons are named for Titans, the race that included Cronos (Saturn), Zeus? father. Neptune?s moons are named for mythological characters associated with water, and Charon was the ferryman of the dead who brought people to Pluto?s realm. By tradition, the discoverer of a moon gets to name it (now subject to approval by the International Astronomical Union). The son of the discoverer of the first two moons of Uranus (Sir William Herschel) decided to name Uranus? moons not for mythological characters, but instead for the king and queen of fairies in Shakespear?s A Midsummer Night?s Dream . This began a tradition whereby all uranian satellites are named for fairy characters in English drama. To read more about the names of the planets and their satellites, go to the U.S. Geological Survey?s nomenclature guide at http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/append7.html . Earth Moon Mars Phobos, Deimos Jupiter Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope Saturn Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Tethys, Calypso, Telesto, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe Uranus Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda,, Ariel, Umbriel, Titania, Oberon Neptune Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid Pluto Charon Image Credit: Image processing by Tim Parker (Jet Propulsion Laboratory) and Paul Schenk and Robert Herrick (Lunar and Planetary Institute), based on NASA images.

The New Solar System

PIA02973

Title	The New Solar System
Original Caption Released with Image	This solar-system montage of the nine planets and 4 large moons of Jupiter in our solar system are set against a false-color view of the Rosette Nebula. The light emitted from the Rosette Nebula results from the presence of hydrogen (red), oxygen (green) and sulfur (blue). Most of the planetary images in this montage were obtained by NASA's planetary missions, which have dramatically changed our understanding of the solar system in the past 30 years. The following lists the mission and link for additional information on each object and image.Mercury/Mariner 10 [ http://photojournal.jpl.nasa.gov/catalog/PIA02418 ]Venus/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA00072 ]Earth/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA00728 ]Moon/Lunar Orbiter [ http://photojournal.jpl.nasa.gov/catalog/PIA00094 ]Mars/Viking Orbiter 1 & 2 [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/wall/mars/hemisph.html ]Jupiter/Voyager 1 [ http://photojournal.jpl.nasa.gov/catalog/PIA01509 ]Io/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA02309 ]Europa/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA00502 ]Ganymede/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA01666 ]Callisto/Galileo [ http://photojournal.jpl.nasa.gov/catalog/PIA01298 ]Saturn/Voyager 1 [ http://photojournal.jpl.nasa.gov/catalog/PIA01383 ]Uranus/Voyager 2 [ http://photojournal.jpl.nasa.gov/catalog/PIA00032 ]Neptune/Voyager 2 [ http://photojournal.jpl.nasa.gov/catalog/PIA02210 ]Pluto/Hubble Space Telescope [ http://photojournal.jpl.nasa.gov/catalog/PIA00827 ]Rosette Nebula/Kitt Peak [ http://www.noao.edu/image_gallery/html/im0557.html ]

Planet Temperatures

title	Planet Temperatures
description	In general, the surface temperature of the planets decreases with increasing distance from the Sun. Venus is an exception because its dense atmosphere acts as a greenhouse and heats the surface to above the melting point of lead (3280C). Mercury rotates slowly and has a thin atmosphere, and consequently, the nightside temperature can be more than 5000C lower than the dayside temperature shown on the diagram. Temperatures for the gas giants (Jupiter, Saturn, Uranus, and Neptune) are shown at a level in the atmosphere equal in pressure to sea level on Earth. Temperatures are in both Fahrenheit and Celsius, and the planets are not shown to scale. Image Credit: Lunar and Planetary Institute

A Solar System Portrait

Title	A Solar System Portrait
Explanation	As the Voyager 1 spacecraft [ http://vraptor.jpl.nasa.gov/voyager/vgrfaqs.html ] headed out of our Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap980517.html ], it looked back and took a parting family portrait [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-solarsystem.html ] of the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ] and planets. From beyond Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap990213.html ], our Solar System looks like a bright star surrounded by faint dots. In the above picture [ http://photojournal.jpl.nasa.gov/cgi-bin/PIAGenCatalogPage.pl?PIA00451 ], the Sun is so bright it is blocked out for contrast. The innermost dots visible, labeled E and V for Earth [ http://antwrp.gsfc.nasa.gov/apod/ap990131.html ] and Venus [ http://www.nasm.edu/ceps/RPIF/VENUS/rpifvenus.html ], are particularly hard to discern. Gas giants Jupiter [ http://www.jpl.nasa.gov/galileo/Jovian.html ] (J) and Saturn [ http://www.seds.org/nineplanets/nineplanets/saturn.html ] (S) are much more noticeable. The outermost planets visible are Uranus [ http://www.hawastsoc.org/solar/eng/uranus.htm ] (U) and Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap980221.html ] (N). Each planet is shown labeled and digitally enhanced in an inset image. Voyager 1 is only one of four human-made objects to leave our Solar System, the other three being Voyager 2, and Pioneer 10 and Pioneer 11.

Uranus: The Tilted Planet

Title	Uranus: The Tilted Planet
Explanation	Uranus is the third largest planet in our Solar System [ http://www.nineplanets.org/overview.html ] after Jupiter [ http://antwrp.gsfc.nasa.gov/apod/jupiter.html ] and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap010826.html http://www.solarviews.com/eng/saturn.htm ]. Uranus [ http://www.nineplanets.org/uranus.html ] is composed mostly of rock and ices, but with a thick hydrogen [ http://chemlab.pc.maricopa.edu/periodic/h.html ] and helium [ http://antwrp.gsfc.nasa.gov/apod/ap010120.html ] atmosphere. The blue hue of Uranus' atmosphere arises from the small amount of methane [ http://scifun.chem.wisc.edu/chemweek/methane/methane.html ] which preferentially absorbs red light. This picture [ http://photojournal.jpl.nasa.gov/cgi-bin/PIAGenCatalogPage.pl?PIA01360 ] was snapped by the Voyager 2 spacecraft [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] in 1986 - the only spacecraft ever to visit Uranus. Uranus [ http://antwrp.gsfc.nasa.gov/apod/uranus.html ] has many moons [ http://antwrp.gsfc.nasa.gov/apod/ap990531.html ] and a ring system [ http://antwrp.gsfc.nasa.gov/apod/ap971126.html ]. Uranus, like Venus [ http://antwrp.gsfc.nasa.gov/apod/venus.html ], has a rotation axis that is greatly tilted and sometimes points near the Sun. It remains an astronomical mystery why Uranus' axis [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1991LPIP...22...59S ] is so tilted. Uranus and Neptune [ http://antwrp.gsfc.nasa.gov/apod/neptune.html ] are quite similar: Uranus is slightly larger but less massive.

First ESA Faint Object Camera Science Images Pluto - the "Double Planet

First ESA Faint Object Camer …

Title	First ESA Faint Object Camera Science Images Pluto - the "Double Planet

Solar System Portrait - 60 F …

Title	Solar System Portrait - 60 Frame Mosaic
Description	The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever "portrait" of our solar system as seen from the outside. In the course of taking this mosaic consisting of a total of 60 frames, Voyager 1 made several images of the inner solar system from a distance of approximately 4 billion miles and about 32 degrees above the ecliptic plane. Thirty-nine wide angle frames link together six of the planets of our solar system in this mosaic. Outermost Neptune is 30 times further from the sun than Earth. Our sun is seen as the bright object in the center of the circle of frames. The wide-angle image of the sun was taken with the camera's darkest filter (a methane absorption band) and the shortest possible exposure (5 thousandths of a second) to avoid saturating the camera's vidicon tube with scattered sunlight. The sun is not large as seen from Voyager, only about one-fortieth of the diameter as seen from Earth, but is still almost 8 million times brighter than the brightest star in Earth's sky, Sirius. The result of this great brightness is an image with multiple reflections from the optics in the camera. Wide-angle images surrounding the sun also show many artifacts attributable to scattered light in the optics. These were taken through the clear filter with one second exposures. The insets show the planets magnified many times. Narrow-angle images of Earth, Venus, Jupiter, Saturn, Uranus and Neptune were acquired as the spacecraft built the wide-angle mosaic. Jupiter is larger than a narrow-angle pixel and is clearly resolved, as is Saturn with its rings. Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposures. From Voyager's great distance Earth and Venus are mere points of light, less than the size of a picture element even in the narrow-angle camera. Earth was a crescent only 0.12 pixel in size. Coincidentally, Earth lies right in the center of one of the scattered light rays resulting from taking the image so close to the sun.
Date	06.06.1990

Solar System Portrait - 60 F …

PIA00451

Imaging Science Subsystem - …

Title	Solar System Portrait - 60 Frame Mosaic
Original Caption Released with Image	The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever "portrait" of our solar system as seen from the outside. In the course of taking this mosaic consisting of a total of 60 frames, Voyager 1 made several images of the inner solar system from a distance of approximately 4 billion miles and about 32 degrees above the ecliptic plane. Thirty-nine wide angle frames link together six of the planets of our solar system in this mosaic. Outermost Neptune is 30 times further from the sun than Earth. Our sun is seen as the bright object in the center of the circle of frames. The wide-angle image of the sun was taken with the camera's darkest filter (a methane absorption band) and the shortest possible exposure (5 thousandths of a second) to avoid saturating the camera's vidicon tube with scattered sunlight. The sun is not large as seen from Voyager, only about one-fortieth of the diameter as seen from Earth, but is still almost 8 million times brighter than the brightest star in Earth's sky, Sirius. The result of this great brightness is an image with multiple reflections from the optics in the camera. Wide-angle images surrounding the sun also show many artifacts attributable to scattered light in the optics. These were taken through the clear filter with one second exposures. The insets show the planets magnified many times. Narrow-angle images of Earth, Venus, Jupiter, Saturn, Uranus and Neptune were acquired as the spacecraft built the wide-angle mosaic. Jupiter is larger than a narrow-angle pixel and is clearly resolved, as is Saturn with its rings. Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposures. From Voyager's great distance Earth and Venus are mere points of light, less than the size of a picture element even in the narrow-angle camera. Earth was a crescent only 0.12 pixel in size. Coincidentally, Earth lies right in the center of one of the scattered light rays resulting from taking the image so close to the sun.

An Auroral Ring on Jupiter

Title	An Auroral Ring on Jupiter
Explanation	Do other planets have aurora? Terrestrial [ http://work.ucsd.edu:5141/cgi-bin/http_webster?terrestrial ] and spacecraft observations have found evidence for aurora on Venus [ http://www.seds.org/nineplanets/nineplanets/venus.html ], Mars [ http://antwrp.gsfc.nasa.gov/apod/ap970609.html http://www.seds.org/nineplanets/nineplanets/mars.html ], Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ], Saturn [ http://www.seds.org/nineplanets/nineplanets/saturn.html ], Uranus [ http://www.seds.org/nineplanets/nineplanets/uranus.html ], and Neptune [ http://www.seds.org/nineplanets/nineplanets/neptune.html ]. In the above false-color photograph [ http://galileo.ivv.nasa.gov/callisto/043097.html ], a good portion of an auroral ring [ http://antwrp.gsfc.nasa.gov/apod/ap970609.html http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996BAAS%2E%2E%2E28%2E2123P&db_key=AST&nosetcookie=1 ] was captured recently in optical light by the Galileo spacecraft [ http://galileo.ivv.nasa.gov/spacecraft.html ] in orbit around Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap970609.html http://antwrp.gsfc.nasa.gov/cgi-bin/cossc/apod_search?jupiter ]. Auroral rings [ http://antwrp.gsfc.nasa.gov/apod/ap970609.html http://www.geo.mtu.edu/weather/aurora/ ] encircle a planet's magnetic pole, and result from charged particles spiraling down magnetic field lines. Although the surroundings near Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap960803.html ] are much different than Earth [ http://antwrp.gsfc.nasa.gov/apod/ap961230.html ], the auroral rings [ http://antwrp.gsfc.nasa.gov/apod/ap970402.html ] appear similar.

Uranus - Final Image

PIA00143

Sol (our sun)

Imaging Science Subsystem - …

Title	Uranus - Final Image
Original Caption Released with Image	This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Voyager was 1 million kilometers (about 600,000 miles) from Uranus when it acquired this wide-angle view. The picture -- a color composite of blue, green and orange frames -- has a resolution of 140 km (90 mi). The thin crescent of Uranus is seen here at an angle of 153 degrees between the spacecraft, the planet and the Sun. Even at this extreme angle, Uranus retains the pale blue-green color seen by ground-based astronomers and recorded by Voyager during its historic encounter. This color results from the presence of methane in Uranus' atmosphere, the gas absorbs red wavelengths of light, leaving the predominant hue seen here. The tendency for the crescent to become white at the extreme edge is caused by the presence of a high-altitude haze Voyager 2 -- having encountered Jupiter in 1979, Saturn in 1981 and Uranus in 1986 -- will proceed on its journey to Neptune. Closest approach is scheduled for Aug 24, 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

Description	Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn.
Full Description	This 1981 Voyager 2 image shows the vast Saturn ring system, as well as three small icy satellites and the shadow of a fourth. Saturn is the second largest planet in the Solar System. It has a volume about 760 times that of Earth. Like Jupiter, Uranus, and Neptune, it has no solid surface, but is instead an enormous sphere of gas which gradually compresses into fluid at great depths beneath the clouds. Most of the visible markings are formed in a layer of ammonia ice clouds, which form at a pressure level in Saturn's atmosphere that is comparable to sea-level atmospheric pressure on Earth. Above those clouds, Saturn's atmosphere, like those of the Sun and the other three gas giant planets, is composed almost exclusively of hydrogen and helium. By contrast, Saturn's rings and icy satellites appear to be composed primarily of water ice. Image reprocessed by USGS. (P-43538)

Lightning on Jupiter

Title	Lightning on Jupiter
Explanation	Does lightning occur only on Earth? Spacecraft in our Solar System have detected radio signals consistent with lightning [ http://wwwghcc.msfc.nasa.gov/lisotd.html ] on other planets, including Venus [ http://www.seds.org/nineplanets/nineplanets/venus.html ], Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ], Saturn [ http://www.seds.org/nineplanets/nineplanets/saturn.html ], Uranus [ http://www.seds.org/nineplanets/nineplanets/uranus.html ], and Neptune [ http://www.seds.org/nineplanets/nineplanets/neptune.html ]. In the above photograph [ http://galileo.ivv.nasa.gov/callisto/050197.html ], optical flashes from Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap970109.html ] were photographed recently by the Galileo orbiter [ http://galileo.ivv.nasa.gov/mission.html ]. Each of the circled dots indicates lightning [ http://www.nofc.forestry.ca/~kanderso/ltgfaq.html ]. The numbers label lines of latitude [ http://www.met.fsu.edu/explores/latlon.html ]. The size of the largest spot is about 500 kilometers across and might be high clouds illuminated by several bright lightning strokes.

August 2006: View of the Pla …

Description	August 2006: View of the Planets
Full Description	Just before the eastern sky brightens with sunrise, three planets and the waning crescent moon join the starry twilight tapestry. Then, as the bright stars of Gemini and Orion fade with oncoming dawn, the planets rise and shine. About 45 minutes before sunrise on Aug. 20 to 22 the planets Venus, Mercury and Saturn dance on the ecliptic -- the plane of Earth's orbit and the imaginary line tracing it in the sky. The sun, moon and planets appear to move along this line. Venus, rising an hour and a half before sunrise, is the easiest to see in the morning sky. Two hundred forty-one million kilometers (150 million miles) distant, Venus is Earth-sized. Mercury, at a distance of 183 million kilometers (114 million miles), is the fastest and smallest of the inner planets and appears brighter than the more distant Saturn. Saturn, 1,517 million kilometers (943 million miles) distant, was at conjunction with the sun just two weeks ago and now rises nearly an hour before sunrise. On Aug. 26 and 27, Saturn pairs with much brighter Venus at dawn. What other planets can we see in late August? Mars sets 45 minutes after sunset by month's end but is lost from view in the twilight, while brilliant Jupiter remains prominent as the only planet visible for a few hours during the late August evenings. Credit: NASA/JPL
Date	August 18, 2006

Orbit of Sedna

Title	Orbit of Sedna
Description	This animation shows the location of the newly discovered planet-like object, dubbed "Sedna," in relation to the rest of the Solar System. Starting at the inner Solar System, which includes the orbits of Mercury, Venus, Earth, and Mars (all in yellow), the view pulls away through the asteroid belt and the orbits of the outer planets beyond (green). Pluto and the distant Kuiper Belt objects are seen next until finally Sedna comes into view. As the field widens the full orbit of Sedna can be seen along with its current location. Sedna is nearing its closest approach to the Sun, its 10,000-year orbit typically takes it to far greater distances. Moving past Sedna, what was previously thought to be the inner edge of the Oort cloud appears. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed.

AC86-7042

Photographer : JPL Range : 1 …

1/24/86

Description	Photographer : JPL Range : 1 illion km. ( 600,000 mi. ) Resolution : 140 km. ( 90 mi. ) P-29539C This Voyager 2 image of Uranus was captured as the spacecraft was leaving Uranus behind on its cruise to Neptune. The image is a color composite of three photographs taken through blue, grren, and orange filters. Thin thin crecent seen here is at an angle of 153 degrees between the the spacecraft, the planet, and the sun. Even at this extreme angle, uranus retains the pale blue-green color seen by the ground based astronomers and recorded by Voyager 2 during its historic encounter, this color results from the presence of methane in Uranus' atmosphere. The gas absorbs red wavelengths of light, leaving the predominant hue seen here. The tendency for the cresent to become white at the extreme edge is cased by the presence of a high-altitude haze. Voyager 2, having encountered Jupiter in 1979, Saturn in 1981, and Uranus in 1986, will proceed on its jouney to Neptune. Closest approach is scheduled for August 24, 1989.
Date	1/24/86

A Jupiter-Venus Conjunction

Title	A Jupiter-Venus Conjunction
Explanation	Venus [ http://www.seds.org/nineplanets/nineplanets/venus.html ] and Jupiter [ http://pds.jpl.nasa.gov/planets/welcome/jupiter.htm ] appeared unusually close together in the sky last month. The conjunction was easily visible to the unaided eye because Venus [ http://www.aspsky.org/html/tnl/18/18.html ] appears brighter than any background star. The two planets were not significantly closer in space - Venus just passed nearly in front of Jupiter as seen from the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap990131.html ]. Visible in the above photograph [ http://www.psiaz.com/polakis/conj0299/conj0299.html ] are actually five planets. The faint dot near the top is Saturn [ http://www.seds.org/nineplanets/nineplanets/saturn.html ]. Venus is the brightest spot near the center, and Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ] is just above it. Perhaps the hardest to see is Mercury [ http://stardate.utexas.edu/resources/ssguide/mercury.html ], visible below Venus but above the foreground Earth [ http://antwrp.gsfc.nasa.gov/apod/ap980904.html ]. A single line nearly connects all the planets [ http://antwrp.gsfc.nasa.gov/apod/ap980825.html ], a result of all planets orbiting the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ] in a single plane called the ecliptic [ http://antwrp.gsfc.nasa.gov/apod/ap970927.html ].

S-1 C & BW -62

Voyager 1 looked back at Sat …

12/4/80

Date	12/4/80
Description	Voyager 1 looked back at Saturn on Nov. 16, 1980, four days after the spacecraft flew past the planet, to observe the appearance of Saturn and its rings from this unique perspective. A few of the spokelike ring features discovered by Voyager appear in the rings as bright patches in this image, taken at a distance of 5.3 million kilometers (3.3 million miles) from the planet. Saturn's shadow falls upon the rings, and the bright Saturn crescent is seen through all but the densest portion of the rings. From Saturn, Voyager 1 is on a trajectory taking the spacecraft out of the ecliptic plane, away from the Sun and eventually out of the solar system (by about 1990). Although its mission to Jupiter and Saturn is nearly over (the Saturn encounter ends Dec. 18, 1980), Voyager 1 will be tracked by the Deep Space Network as far as possible in an effort to determine where the influence of the Sun ends and interstellar space begins. Voyager 1's flight path through interstellar space is in the direction of the constellation Ophiuchus. Voyager 2 will reach Saturn on August 25, 1981, and is targeted to encounter Uranus in 1986 and possibly Neptune in 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California. #####

Neptune: Big Blue Giant

Title	Neptune: Big Blue Giant
Explanation	This picture was taken by the Voyager 2 [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft in 1986 - the only spacecraft ever to visit Neptune. Neptune [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/neptune.html ] will be the farthest planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] until 1999, when the elliptical orbit of Pluto will cause it to once again resume this status. Neptune [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/neptune.html ], like Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ], is composed mostly of liquid water, methane and ammonia, is surrounded by a thick gas atmosphere of mostly hydrogen and helium, and has many moons and rings. Neptune [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-neptune.html ]'s moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] is unlike any other and has active volcanoes. The nature of Triton [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/triton.html ]'s unusual orbit around Neptune is the focus of much discussion and speculation. Tomorrow's picture: Pluto: The Frozen Planet

Neptune

PIA02205

Sol (our sun)

Imaging Science Subsystem - …

Title	Neptune
Original Caption Released with Image	This image of the planet Neptune was taken by the Voyager 2spacecraft on January 23, 1989, about seven months before its scheduled August 25 encounter. The spacecraft was 310 million kilometers (192 million miles) from the planet, looking from 34 degrees south of Neptune's equator through the "clear" filter. Similar images from Earth-based telescopes had shown a featureless disk, through red filters, chosen to mark methane gas, revealed irregular-shaped features associated with high-altitude hazes. The Voyager data reveal cloud structure at lower altitudes where the circulation is apparently arranged in parallel east-west bands, as is the case on Jupiter, Saturn, and Uranus. In the original image, the bright bands are about 10 percent brighter than the dark band circling the South pole. This is about the same contrast shown by Saturn, and ten times more than Uranus. The brightening and sawtooth edge around the right side are artifacts of the data processing. The Voyager project is managed by the Jet Propulsion Laboratory for the NASA Office of Space Science and Applications.

Jupiter Flyby

title	Jupiter Flyby
description	Although the main mission of the New Horizons spacecraft is to explore the Pluto system and the Kuiper Belt of icy objects, it will first fly by the solar system's largest planet, Jupiter, in 2007 - a little over a year after the planned launch date. In this artist's rendering, New Horizons is just past its closest approach to the planet. Near the Sun are Earth, Venus and Mercury. The dim crescent shape at the upper right of the Sun is Callisto, the outermost of Jupiter's four largest moons. Just left of Jupiter is Europa. Image Credit: Southwest Research Institute (Dan Durda)/Johns Hopkins University Applied Physics Laboratory (Ken Moscati)

Planets In The Sun

Title	Planets In The Sun
Explanation	Today [ http://science.nasa.gov/headlines/y2000/ast02may_1.htm ], all five naked-eye planets [ http://www.seds.org/nineplanets/nineplanets/ ] (Mercury, Venus, Mars, Jupiter, Saturn) plus the Moon and the Sun [ http://helios.gsfc.nasa.gov/ sun.html ] will at least approximately line-up. As viewed [ http://drumright.ossm.edu/astronomy/conjunctions.html ] from planet Earth, they will be clustered within about 26 degrees, the closest alignment for all these celestial bodies [ http://science.nasa.gov/headlines/y2000/ ast30mar_1m.htm#alignments ] since February 1962, when there was a solar eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap990818.html ]! Such planetary alignments [ http://www.griffithobs.org/SkyAlignments.html ] are not dangerous, except of course that the Sun might hurt your eyes when you look at it [ http://antwrp.gsfc.nasa.gov/apod/ap981212.html ]. So it might be easier [ http://sohowww.nascom.nasa.gov/hotshots/ ] to appreciate today's solar system [ http://space.jpl.nasa.gov/ ] spectacle if

Charon Discovery Image

title	Charon Discovery Image
date	06.22.1978
description	On 22 June 1978, an astronomer at the U.S. Naval Observatory in Washington, D.C. was making routine measurements of photographic plates taken with the 1.55-meter (61-inch) Kaj Strand Astrometric Reflector at the USNO Flagstaff Station in Arizona. The purpose of these images was to refine the orbit of the far-flung planet Pluto to help compute a better ephemeris for this distant object. Astronomer James W. Christy had noticed that a number of the images of Pluto appeared elongated, but images of background stars on the same plate did not. Other plates showed the planet as a tiny, round dot. Christy examined a number of Pluto images from the USNO archives, and he noticed the elongations again. Furthermore, the elongations appeared to change position with respect to the stars over time. After eliminating the possibility that the elongations were produced by plate defects and background stars, the only plausible explanation was that they were caused by a previously unknown moon orbiting Pluto at a distance of about 19,600 kilometers (12,100 miles) with a period of just over six days. On 7 July 1978, the discovery was formally announced to the astronomical community and the world by the IAU Central Bureau for Astronomical Telegrams via IAU Circular 3241. The discovery received the provisional designation "1978 P 1", Christy proposed the name "Charon", after the mythological ferryman who carried souls across the river Acheron, one of the five mythical rivers that surrounded Pluto's underworld. Over the course of the next several years, another USNO astronomer, the late Robert S. Harrington, calculated that Pluto and its newly-found moon would undergo a series of mutual eclipses and occultations, beginning in early 1985. On 17 February 1985 the first successful observation of one of these transits was made at with the 0.9-meter (36-inch) reflector at the University of Texas McDonald Observatory, within 40 minutes of Harrington's predicted time. The IAU Circular announcing these confirming observations was issued on 22 February 1985. With this confirmation, the new moon was officially named Charon. Pluto was discovered at Lowell Observatory in 1930 by the late Clyde W. Tombaugh, an amateur astronomer from Kansas who was hired by the Observatory specifically to photograph the sky with a special camera and search for the planet predicted by the Observatory's founder, Percival Lowell. Lowell had deduced the existence of a "Planet X" by studying small anomalies in the orbits of Uranus and Neptune. As it turned out, Pluto's discovery was almost entirely serendipitous, Pluto's tiny mass was far too small to account for the anomalies, which were resolved when Voyager 2 determined more precise masses for Uranus and Neptune. The discovery of Charon has led to a much better understanding of just how tiny Pluto is. Its diameter is about 2274 km (1413 miles), and its mass is 0.25% of the mass of the Earth. Charon has a diameter of about 1172 kilometers (728, miles) and a mass of about 22% that of Pluto. The two worlds circle their common center of mass with a period of 6.387 days and are locked in a "super-synchronous" rotation: observers on Pluto's surface would always see Charon in the same part of the sky relative to their local horizon. Normally Pluto is considered the most distant world in the solar system, but during the period from January 1979 until February 1999 it was actually closer to the Sun than Neptune. It has the most eccentric and inclinced orbit of any of the major planets. This orbit won't bring Pluto back to its discovery position until the year 2178! Image Credit: U.S. Naval Observatory

Irregular Moons Discovered Around Uranus

Irregular Moons Discovered A …

Title	Irregular Moons Discovered Around Uranus
Explanation	Where did these two irregular moons of Uranus [ http://www.seds.org/nineplanets/nineplanets/uranus.html ] originate? Last week two previously undiscovered moons [ http://www.cita.utoronto.ca/~gladman/utpress.html ] of the distant gas planet were confirmed [ http://cfa-www.harvard.edu/iauc/06700/06765.html ], the first in irregular orbits. All fifteen previously known moons [ http://www.seds.org/nineplanets/nineplanets/uramoons.html ] of Uranus [ http://bang.lanl.gov/solarsys/uranus.htm ] are 'regular', circling near the planet's equator. Most of these were discovered by the passing Voyager 2 spacecraft [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ] in 1986. These newly discovered moons [ http://www.news.cornell.edu/science/Oct97/new_moons.hrs.html ] are thought to be odd-shaped and about 100 km across. They are considered irregular, though, because they orbit in odd directions and far from Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ]. If Uranus' irregular moons have the same origin as those orbiting Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ], Saturn [ http://pds.jpl.nasa.gov/planets/welcome/saturn.htm ], and Neptune [ http://spacelink.msfc.nasa.gov/Instructional.Materials/Curriculum.Materials/Sciences/Astronomy/Our.Solar.System/Neptune/ ], then they were probably caught from orbits around the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960518.html ]. Moons like this are discovered by their motion. One of these moons is shown above [ http://www.cita.utoronto.ca/~gladman/ ] as the circled point of light moving from left to right. (To stop the movie from repeating, click "stop" on most browsers.)

Neptune

PIA01998

Sol (our sun)

Imaging Science Subsystem - …

Title	Neptune
Original Caption Released with Image	This image of Neptune was taken through the clear filter of the narrow-angle camera on July 16 when the Voyager 2 spacecraft was at a range of 57,000,000 kilometers (35 million miles). The image was processed by computer to show the newly resolved dark oval feature embedded in the middle of the dusky southern collar. The large dark spot nearer the equator is also prominent on the left edge of the disk. The new small dark spot rotates faster than the large dark spot indicating that the winds on Neptune have different velocities at different latitudes as is the case for Jupiter, Saturn and Uranus.

Cosmic Conjunction

title	Cosmic Conjunction
description	Five planets - Mercury, Venus, Mars, Jupiter and Saturn - gather over the ancient Stonehenge monument in England. Image Copyright: Philip Perkins

Sky and Planets

Title	Sky and Planets
Explanation	On February 10th, an evocative [ http://www.jps.net/ssumner/ ] evening sky above Rocklin, California, USA inspired astrophotographer Steve Sumner to record this remarkable sight - five planets and the Moon. Near its first quarter phase, the bright Moon [ http://lunar.arc.nasa.gov/ ] was intentionally overexposed but Saturn [ http://www.jpl.nasa.gov/cassini/ ], Jupiter [ http://galileo.jpl.nasa.gov/ ], Mars [ http://mars.jpl.nasa.gov/ ], and Mercury [ http://sd-www.jhuapl.edu/MESSENGER/ ] (and, of course, planet Earth's [ http://www.earth.nasa.gov/ ] horizon) are all clearly visible in the deepening twilight. Notably absent in this grouping of naked-eye planets is Venus [ http://antwrp.gsfc.nasa.gov/apod/ap990903.html ] which is still putting in an early appearance as the morning star [ http://ispec.scibernet.com/station/morn_star.html ]. This month, Mercury has joined Venus in the dawn twilight while Saturn, Jupiter, and Mars still shine brightly in the western sky at nightfall [ http://www.skypub.com/sights/sights.shtml ] making another gorgeous close grouping with the crescent Moon [ http://www.inconstantmoon.com/ ].

Trailing Planets

Title	Trailing Planets
Explanation	Positioning his camera and tripod on planet [ http://nfo.edu/astro/planets.htm ] Earth, near Maricopa, Arizona, USA, astrophotographer [ http://pages.prodigy.net/pam.orman/joemoon/ JoeExposurestwilight.html ] Joe Orman created this trailing display of the ongoing sky-full-of-planets [ http://www.darkhorizons.org/planets.htm ] on May 3rd. He initially captured the grouping in a 20 second long time exposure recording the positions of the bright planets and stars. Covering the camera lens for five minutes, he then exposed the same frame for 45 minutes, tracing [ http://antwrp.gsfc.nasa.gov/apod/ap980912.html ] the gentle arcs of the celestial wanderers [ http://www.sciam.com/1999/0999issue/0999rennie.html ] as the Earth's rotation carried them toward the western horizon. Of course these planets, Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap991111.html ], Venus [ http://antwrp.gsfc.nasa.gov/apod/ap010308.html ], Mars [ http://antwrp.gsfc.nasa.gov/apod/ap010627.html ], Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap960723.html ], and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap020222.html ] all still dazzle [ http://science.nasa.gov/headlines/y2002/ 24apr_relax.htm ] in western skies near sunset, but sky gazers who want to see Mercury should look soon. Mercury starts the evening closest to the horizon - visible here above the wide bright trail left by Venus - and in the coming days Mercury will be the first to leave the evening sky entirely as it moves closer to the setting Sun. Tonight Venus and Mars [ http://science.nasa.gov/headlines/y2002/images/relax/ skymap_north_10may02.gif ] will appear very close together, separated by only one third of a degree.

Solar System Montage of Voya …

Title	Solar System Montage of Voyager Images
Full Description	This montage of images taken by the Voyager spacecraft of the planets and four of Jupiter's moons is set against a false-color Rosette Nebula with Earth's moon in the foreground. Studying and mapping Jupiter, Saturn, Uranus, Neptune, and many of their moons, Voyager provided scientists with better images and data than they had ever had before or expected from the program. Although launched sixteen days after Voyager 2, Voyager 1's trajectory was a faster path, arriving at Jupiter in March 1979. Voyager 2 arrived about four months later in July 1979. Both spacecraft were then directed to Saturn with Voyager 1 arriving in November 1980 and Voyager 2 in August 1981. Voyager 2 was then diverted to the remaining gas giants, Uranus in January 1986 and Neptune in August 1989. Data collection continues by both Voyager 1 and 2 as the renamed Voyager Interstellar Mission searches for the edge of the solar wind influence (the heliopause) and exits the Solar System. A shortened list of the discoveries of Voyager 1 and 2 include:the discovery of the Uranian and Neptunian magnetospheres (magnetic environments caused by various types of planet cores), the discovery of twenty-two new satellites including three at Jupiter, three at Saturn, ten at Uranus, and six at Neptune, Io was found to have active volcanism (the only other Solar System body than Earth to be confirmed), Triton was found to have active geyser-like structures and an atmosphere, Auroral Zones (where gases become excited after being hit by solar particles) were discovered at Jupiter, Saturn, and Neptune, Jupiter was found to have rings, Neptune, originally thought to be too cold to support such atmospheric disturbances, had large-scale storms.
Date	UNKNOWN
NASA Center	Jet Propulsion Laboratory

Gas Planet Sizes

title	Gas Planet Sizes
description	Jupiter, Saturn, Uranus, and Neptune are known as the jovian (Jupiter-like) planets because they are all gigantic compared with Earth, and they have a gaseous nature like Jupiter's. The jovian planets are also referred to as the gas giants, although some or all of them might have small solid cores. This diagram shows the approximate relative sizes of the jovian planets. Image Credit: Lunar and Planetary Institute

Venus: Earth's Sister Planet

Title	Venus: Earth's Sister Planet
Explanation	This picture in visible light was taken by the Galileo [ http://nssdc.gsfc.nasa.gov/planetary/galileo.html ] spacecraft. Venus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/venus.html ] is very similar to Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ] in size and mass - and so is sometimes referred to as Earth's sister planet - but Venus has a quite different climate. Venus' [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/venus.html ] thick clouds and closeness to the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] (only Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap950814.html ] is closer) make it the hottest planet - much hotter than the Earth. Humans could not survive there, and no life of any sort has ever been found. When Venus [ http://nssdc.gsfc.nasa.gov/photo_gallery/PhotoGallery-Venus.html ] is visible it is usually the brightest object in the sky after the Sun and the Moon. More than 20 spacecraft have visited Venus including Venera 9, which landed on the surface, and Magellan [ http://stardust.jpl.nasa.gov/mveg/guide.html ], which used radar to peer through the clouds and make a map of the surface. There are still many things about Venus's unusual atmosphere that astronomers don't understand. Tomorrow's picture: Uranus: The Tilted Planet

Gas Giant Interiors

title	Gas Giant Interiors
description	Jupiter Jupiter's composition is mainly hydrogen and helium. In contrast to planetary bodies covered with a hard surface crust (the Earth, for example), the jovian surface is gaseous-liquid, rendering the boundary between the atmosphere and the planet itself almost indistinguishable. Below the roughly 1000-kilometer-thick atmosphere, a layer of liquid hydrogen extends to a depth of 20,000 kilometers. Even deeper, it is believed that there is a layer of liquid metallic hydrogen at a pressure of 3 million bars. The planet core is believed to comprise iron-nickel alloy, rock, etc., at a temperature estimated to exceed 20,000C. Saturn As with Jupiter, Saturn is mainly composed of hydrogen and helium and is observed to be of extremely low density. In fact, Saturn's mean density is only about two-thirds that of water. The Saturn atmosphere comprises, in descending order of altitude, a layer of ammonia, a layer of ammonium hydrogen sulfide, and a layer of ice. Below this, the saturnian surface is a stratum of liquid hydrogen (as in the case of Jupiter) underlain with a layer of liquid metallic hydrogen. It is believed that the liquid hydrogen layer of Saturn is thicker than that of Jupiter, while the liquid metallic hydrogen layer may be thinner. The planet's core is estimated to be composed of rock and ice. Uranus Uranus is gaseous in composition, mainly comprising hydrogen and helium as in the case of Jupiter and Saturn. The planet atmosphere is mostly hydrogen but also includes helium and methane. The planet core is estimated to be rock and ice encompassed by an outer layer of ice comprised of water, ammonium, and methane. Neptune The atmosphere of Neptune consists of mainly hydrogen, methane and helium, similar to Uranus. Below it is a liquid hydrogen layer including helium and methane. The lower layer is made up of the liquid hydrogen compounds oxygen and nitrogen. It is believed that the planet core comprises rock and ice. Neptune's average density, as well as the greatest proportion of core per planet size, is the greatest among all the gaseous planets. Image Credit: Lunar and Planetary Institute

New Horizons at Jupiter

Title	New Horizons at Jupiter
Explanation	Headed for the first close-up exploration of the Pluto-Charon system [ http://www.plutoportal.net/ ] and the icy denizens of the Kuiper belt [ http://www.ifa.hawaii.edu/faculty/jewitt/kb.html ], NASA's New Horizons [ http://pluto.jhuapl.edu/mission.htm ] spacecraft is pictured here in an artist's vision of the robot probe outward bound. The dramatic scene [ http://www.swri.org/press/jest.htm ] depicts the 465 kilogram spacecraft about one year after a planned 2006 launch, following a flyby of gas giant Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap031114.html ]. While the Jupiter flyby [ http://www.swri.edu/9what/releases/ JEST.htm ] will be used as a gravity assist [ http://www.jpl.nasa.gov/basics/grav/primer.html ] maneuver to save fuel and cut travel time to the outer reaches of the Solar System [ http://www.seds.org/nineplanets/nineplanets/ nineplanets.html ], it will also provide an opportunity to test instruments and study the giant planet, its moons, and magnetic fields. The Sun is seen from eight hundred million kilometers away, with inner planets Earth, Venus, and Mercury aligned [ http://antwrp.gsfc.nasa.gov/apod/ap001014.html ] on the left. A dim crescent of outermost Galilean moon Callisto [ http://antwrp.gsfc.nasa.gov/apod/ap010731.html ], orbiting Jupiter just inside of the spacecraft's trajectory, appears to the upper right of the fading Sun. Left of Jupiter itself is Europa [ http://antwrp.gsfc.nasa.gov/apod/ap030919.html ] and in the distant background are the faint, unresolved stars and dust clouds of the Milky Way [ http://home.arcor-online.de/axel.mellinger/ ]. New Horizons' planned arrival at Pluto-Charon [ http://pluto.jhuapl.edu/plutocharon.htm ] is in the summer of 2015.

Pioneer 10 Trajectory

Title	Pioneer 10 Trajectory
Full Description	This image, drawn in 1970, is an artist's rendering of the Pioneer 10 spacecraft trajectory, with the planets labeled and a list of the instruments that were intended to be flown. Before the use of computer animation, artists were hired by JPL and NASA to depict a spacecraft in flight, for use as a visual aid to promote the project during development. Pioneer 10 was managed by NASA Ames Research Center in Moffett Field, California. The Pioneer F spacecraft, as it was known before launch, was designed and built by TRW Systems Group, Inc. JPL developed three instruments that flew on the spacecraft: Magnetic Fields, S-Band Occultation, and Celestial Mechanics, as well as running the Deep Space Network which provided tracking and data system support. Caltech was responsible for the Jovian Infrared Thermal Structure experiment. Pioneer was very successful, crossing the orbit of Mars and the asteroid belt beyond it, encountering, studying, and photographing Jupiter, then crossing the orbits of Saturn, Uranus, and Neptune. It left the solar system in 1983 and has been contacted several times in the past few years. As of July 2001, the spacecraft was still able to send a return signal to Earth. At Jupiter, the experiments of Pioneer were used to examine the environmental and atmospheric characteristics of the giant planet. Pioneer was also the vital precursor to all future flights to the outer solar system. It determined that a spacecraft could safely fly through the asteroid belt. It also measured the intensity of Jupiter's radiation belt so that NASA could design future Jupiter (and other outer planets) orbiters.
Date	03/07/1972
NASA Center	Jet Propulsion Laboratory

Three Planets in Dawn Skies

Title	Three Planets in Dawn Skies
Explanation	Three children of the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap061116.html ] rise in the east in this peaceful dawn skyview recorded December 7th near Bolu, Turkey. Inner planet Mercury [ http://kids.nineplanets.org/mercury.htm ], fresh from its second transit [ http://antwrp.gsfc.nasa.gov/apod/ap061114.html ] of the 21st century, stands highest in the bright sky at the top right. Gas giant Jupiter [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ jupiterfact.html ] lies below the cloud bank near picture center. A newsworthy Mars [ http://www.nasa.gov/mission_pages/mars/news/ mgs-20061206.html ] is also visible, right of Jupiter and just above the dark cloud bank. On Sunday, these planets will form a much tighter grouping [ http://skytonight.com/observing/ataglance ] before sunrise [ http://niteskys.com/mercury_mars_jupiter_120806.html ], while in the coming days the western sky after sunset will be ruled by brilliant planet Venus [ http://www.esa.int/SPECIALS/Venus_Express/ ], also known as the evening star.

Nashville Four Planet Skylin …

Title	Nashville Four Planet Skyline
Explanation	So far this February, evening skies [ http://antwrp.gsfc.nasa.gov/apod/ap000504.html ] have been blessed with a glorious Moon and three bright planets, Venus [ http://www.library.utoronto.ca/utel/rp/poems/ longfe10.html ], Jupiter, and Saturn. But just last week, on January 30th, an extreme wide-angle lens allowed astrophotographer Larry Koehn to capture this twilight view of Moon and four planets above [ http://www.seds.org/nineplanets/nineplanets/ see.html ] Nashville, Tennessee, USA. These major solar system [ http://space.jpl.nasa.gov/ ] bodies lie along the ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap001014.html ] and so follow a diagonal line through the picture. Starting near the upper left corner is bright Jupiter [ http://starchild.gsfc.nasa.gov/docs/StarChild/ solar_system_level2/jupiter.html ], which takes on a slightly triangular shape due to the lens distortion. Just below and right of Jupiter is Saturn [ http://www.jpl.nasa.gov/cassini/english/kids/ saturn_in_sky.html ]. Continuing along the diagonal toward the lower right is an overexposed, six day old Moon [ http://www.inconstantmoon.com/ ] and brilliant Venus seemingly embedded in clouds. The fourth planet pictured is Mercury. Notoriously hard to see from planet Earth because it never wanders far from the Sun, Mercury is [ http://antwrp.gsfc.nasa.gov/apod/ap991111.html ] visible just above the lower right corner. The line from Jupiter to Mercury spans about 92 degrees across the Nashville sky.

Mercury: Closest Planet to t …

Title	Mercury: Closest Planet to the Sun
Explanation	This picture was compiled from images taken by the NASA spacecraft Mariner 10 which flew by the planet three times in 1974. Mercury [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/mercury.html ] is the closest planet to the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ], the second hottest planet (Venus gets hotter), and the second smallest planet (Pluto is smaller). Mercury [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/mercury.html ] rotates so slowly that one day there - "day" meaning the normal time it takes from sunset to sunset - lasts 176 days on Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ]. It is difficult to see Mercury [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-mercury.html ] not because it is dim but because it always appears near the Sun, and is therefore only visible for a short time just after sunset or just before sunrise. Mercury is made of rocky material like Earth. No one knows why Mercury has the magnetic field that it does. Tomorrow's picture: Venus: Earth's Sister Planet

Voyager Spacecraft During Vibration Testing

Voyager Spacecraft During Vi …

Title	Voyager Spacecraft During Vibration Testing
Full Description	Two Voyager spacecraft were launched in 1977 to explore the outer planets and some of their satellites. A prototype Voyager spacecraft is shown at NASA's Jet Propulsion Laboratory in Pasadena, California, as it successfully passed vibration tests which simulated the expected launch environment. The large parabolic antenna at the top is 3.7 meters in diameter and was used at both S-band and X-band radio frequencies for communicating with Earth over the great distances from the outer planets. The spacecraft received electrical power from three nuclear power sources (lower left). The shiny cylinder on the left side under the antenna contained a folded boom, which extended after launch to hold a magnetometer instrument thirteen meters away from the body of the spacecraft. The truss-like structure on the right side is the stowed instrument boom which supported three science instruments and a scan platform. The scan platform allowed the accurate pointing of two cameras and three other science instruments at Jupiter, Saturn, the rings of Saturn, Jupiter's moons, Saturn's moons, Uranus, moons of Uranus, and Neptune.
Date	03/25/1977
NASA Center	Jet Propulsion Laboratory

Planets in the West

Title	Planets in the West
Explanation	Have you seen any bright planets lately? Chances are if you've been outside under clear skies [ http://currentsky.com/ ] just after sunset, then you have. Now shining in the west as bright "stars [ http://nfo.edu/astro/planets.htm ]" in the night sky, are all five planets of the solar system known to [ http://www.nasm.si.edu/ceps/etp/discovery/ etpdiscovery.html ] ancient astronomers - Mercury, Venus, Mars [ http://mars.jpl.nasa.gov/ funzone.html ], Saturn, and Jupiter [ http://www.seds.org/nineplanets/nineplanets/ jupiter.html ]. Recorded from Holt, Michigan, USA about 40 minutes after sunset on April 14th, this digital image [ http://www.pa.msu.edu/people/frenchj/const/index2.html ] captures three of them, Venus, Mars, and Saturn [ http://www.jpl.nasa.gov/solar_system/planets/ saturn_index.html ], along with a young crescent Moon [ http://antwrp.gsfc.nasa.gov/apod/ap000728.html ]. Also indicated are the Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap010506.html ] star cluster and bright red giant star Aldebaran [ http://www.earthsky.com/Features/ Skywatching/pronounce.html ] in Taurus. Mercury [ http://www.psrd.hawaii.edu/Jan97/ MercuryUnveiled.html ], setting, is lost in the trees and glow along the horizon, while Jupiter is off the top of this view. The coming weeks [ http://www.darkhorizons.org/planets.htm ] will see photo opportunities galore as all five planets gradually move closer together, posing after sunset with the Moon and stars in the western sky [ http://www.skyviewcafe.com/skyview.shtml ]. Venus [ http://antwrp.gsfc.nasa.gov/apod/ap020330.html ], Mars, and Saturn will form the closest trio, drawing within a 5 degree circle (about the apparent size of your fist with arm extended) above Aldebaran by May 3rd.

Saturn and its rings

PIA01969

Sol (our sun)

Imaging Science Subsystem - …

Title	Saturn and its rings
Original Caption Released with Image	Voyager 1 looked back at Saturn on Nov. 16, 1980, four days after the spacecraft flew past the planet, to observe the appearance of Saturn and its rings from this unique perspective. A few of the spokelike ring features discovered by Voyager appear in the rings as bright patches in this image, taken at a distance of 5.3 million kilometers (3.3 million miles) from the planet. Saturn's shadow falls upon the rings, and the bright Saturn crescent is seen through all but the densest portion of the rings. From Saturn, Voyager 1 is on a trajectory taking the spacecraft out of the ecliptic plane, away from the Sun and eventually out of the solar system (by about 1990). Although its mission to Jupiter and Saturn is nearly over (the Saturn encounter ends Dec. 18, 1980), Voyager 1 will be tracked by the Deep Space Network as far as possible in an effort to determine where the influence of the Sun ends and interstellar space begins. Voyager 1's flight path through interstellar space is in the direction of the constellation Ophiuchus. Voyager 2 will reach Saturn on August 25, 1981, and is targeted to encounter Uranus in 1986 and possibly Neptune in 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California.

Seen here is a full-scale mo …

Description

Seen here is a full-scale model of one of the twin Voyager spacecraft, which was sent to explore the giant outer planets in our solar system. Voyager 2 was launched August 20, 1977 followed by the launch of Voyager 1 sixteen days later. Both spacecraft visited Jupiter and Saturn with Voyager 2 continuing its journey to Uranus and Neptune. In spring 1990, Voyager 2 transmitted images looking back across the span of the entire solar system. Both Voyagers continue to explore interstellar space.

Voyager 2 Launch

Title	Voyager 2 Launch
Full Description	Voyager 2 was launched August 20, 1977, sixteen days before Voyager 1 aboard a Titan-Centaur rocket. Their different flight trajectories caused Voyager 2 to arrive at Jupiter four months later than Voyager 1, thus explaining their numbering. The initial mission plan for Voyager 2 specified visits only to Jupiter and Saturn. The plan was augmented in 1981 to include a visit to Uranus, and again in 1985 to include a flyby of Neptune. After completing the tour of the outer planets in 1989, the Voyager spacecraft began exploring interstellar space. The Voyager mission has been managed by NASA's Office of Space Science and the Jet Propulsion Laboratory.
Date	08/20/1977
NASA Center	Kennedy Space Center

Planetary Alignment. LASCO C3 image showing Jupiter, Saturn, Mercury, and Venus simultaneously on May 15, 2000.

Planetary Alignment. LASCO C …

Description	Planetary Alignment. LASCO C3 image showing Jupiter, Saturn, Mercury, and Venus simultaneously on May 15, 2000.

Sedna Orbit Animation

PIA05565

Samuel Oschin Telescope

Title	Sedna Orbit Animation
Original Caption Released with Image	This animation shows the location of the newly discovered planet-like object, dubbed "Sedna," in relation to the rest of the solar system. Starting at the inner solar system, which includes the orbits of Mercury, Venus, Earth, and Mars (all in yellow), the view pulls away through the asteroid belt and the orbits of the outer planets beyond (green). Pluto and the distant Kuiper Belt objects are seen next until finally Sedna comes into view. As the field widens the full orbit of Sedna can be seen along with its current location. Sedna is nearing its closest approach to the Sun, its 10,000 year orbit typically takes it to far greater distances. Moving past Sedna, what was previously thought to be the inner edge of the Oort cloud appears. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed.

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

Planets Over Stonehenge

Title	Planets Over Stonehenge
Explanation	Stonehenge [ http://antwrp.gsfc.nasa.gov/apod/ap990912.html ], four thousand year old [ http://antwrp.gsfc.nasa.gov/apod/ap980408.html ] monument to the Sun [ http://www.hao.ucar.edu/public/education/archeoslides/ index.html ], provides an appropriate setting for this delightful snapshot [ http://www.astrocruise.com/planets.htm ] of the Sun's children [ http://www.seds.org/nineplanets/nineplanets/ ] gathering in planet Earth's sky. While the massive stone [ http://www.amherst.edu/~ermace/sth/poetry.html ] structure dates from around 2000 B.C. [ http://mathforum.org/dr.math/problems/masell10.1.97.html ], this arrangement of the visible planets [ http://skyandtelescope.com/observing/objects/planets/ article_572_1.asp ] was recorded only a few days ago on the evening of May 4th, 2002 A.D. Bright Jupiter stands highest above the horizon at the upper left. A remarkable, almost equilateral triangle [ http://mathforum.org/dr.math/faq/formulas/ faq.triangle.html ] formed by Saturn (left), Mars (top), and Venus (right) is placed just above the stones near picture center. Fighting the glow of the setting sun, Mercury can be spotted closest to the horizon, below and right of the planetary triad. Still easy to enjoy [ http://science.nasa.gov/headlines/y2002/24apr_relax.htm ] for casual sky gazers, this photogenic and slowly shifting planetary grouping [ http://science.nasa.gov/spaceweather/planets/ gallery_may02.html ] will be joined by a young crescent [ http://antwrp.gsfc.nasa.gov/apod/ap020419.html ] Moon beginning Monday, May 13.

A77-0849

Artist: unknown (JPL) Saturn …

7/6/77

Description	Artist: unknown (JPL) Saturn Voyager Mission Artwork depicts the spacecraft's path on it's journey to Saturn as it passed above the orbits of Mercury, Venus, Earth, Mars and around Jupiter.
Date	7/6/77

AC77-0849

Artist: unknown (JPL) Saturn …

7/6/77

Description	Artist: unknown (JPL) Saturn Voyager Mission Artwork depicts the spacecraft's path on it's journey to Saturn as it passed above the orbits of Mercury, Venus, Earth, Mars and around Jupiter.
Date	7/6/77

Dusk of the Planets

Title	Dusk of the Planets
Explanation	A great grouping of planets [ http://www.nineplanets.org/ ] is now visible [ http://CarnegieScienceCenter.org/exhibits/planet_calendar.asp ] to the west just after sunset. Over the next two weeks, Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap010819.html ], Venus [ http://antwrp.gsfc.nasa.gov/apod/ap010916.html ], Earth, Mars [ http://antwrp.gsfc.nasa.gov/apod/ap010628.html ], Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap020205.html ], and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap020215.html ] -- the innermost six planets of our Solar System [ http://www.nineplanets.org/overview.html ] -- can be seen in a single knowing glance. The image on the left [ http://www.astropix.com/HTML/H_OTHER/PLANETS.HTM ] captured them all in one frame. Connecting the planetary dots delineates the edge-on ecliptic [ http://antwrp.gsfc.nasa.gov/apod/ap990529.html ], the plane in which the planets orbit the Sun [ http://csep10.phys.utk.edu/astr161/lect/retrograde/copernican.html ]. The shot was taken on April 23 near Chatsworth, New Jersey [ http://www.state.nj.us/ ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ], and even includes scattered light from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap000403.html ] and the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ]. Besides the planets, the Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap010506.html ] and Hyades [ http://www.astro.uiuc.edu/~kaler/sow/hyades-p.html ] open clusters [ http://www.seds.org/messier/open.html ] of stars are visible [ http://www.planetary.org/html/news/articlearchive/headlines/2002/alignment.htm ].

The Rare Venus Transit

NASA joined the world June 8 …

6/9/08

Description	NASA joined the world June 8, 2004, in viewing a rare celestial event, one not seen by any person now alive. The "Venus transit" -- the apparent crossing of our planetary neighbor in front of the sun -- was captured from the unique perspective of NASA's sun-observing TRACE spacecraft. The top image shows Venus on the eastern limb of the sun. The faint ring around the planet comes from the scattering of its atmosphere, which allows some sunlight to show around the edge of the otherwise dark planetary disk. The faint glow on the disk is an effect of the TRACE telescope. The bottom left image is in the ultraviolet, and the bottom right image is in the extreme ultraviolet. The last "Venus transit" occurred more than a century ago, in 1882, and was used to compute the distance between Earth and the sun. Scientists with NASA's Kepler mission hope to discover Earth-like planets orbiting other stars by searching for transits similar to this one. If people missed the June 8, 2004, Venus transit, they will have another chance in 2012 on June 6. After that, there will not be another Venus transit until Dec. 11, 2117. Image credit: NASA/LMSAL > View QuickTime movies in ultraviolet: 4.2 Mb \| 1.4 Mb
Date	6/9/08

Moon and Planets by the Eiff …

Title	Moon and Planets by the Eiffel Tower
Explanation	The great evening grouping of planets [ http://antwrp.gsfc.nasa.gov/apod/ap020429.html ] is coming to an end. Before all the planets [ http://antwrp.gsfc.nasa.gov/apod/ap020510.html ] went their own separate directions [ http://CarnegieScienceCenter.org/exhibits/planet_calendar.asp ], however, the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ] was kind enough to pose [ http://science.nasa.gov/spaceweather/planets/gallery_may02.html ] with some of them. The planets [ http://www.nineplanets.org ] in the above picture [ http://perso.club-internet.fr/legault/planets.html ], taken last week, are Venus [ http://antwrp.gsfc.nasa.gov/apod/ap970507.html ] and Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap020205.html ]. Mars [ http://www.nineplanets.org/mars.html ], Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap010702.html ], and even Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap000320.html ] appear to the lower right of Venus [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-venus.html ] but are too dim to be seen. Over the next two weeks, the Moon will rise [ http://aa.usno.navy.mil/data/docs/RS_OneYear.html ] later and later passing a full phase [ http://antwrp.gsfc.nasa.gov/apod/ap990419.html ] on May 26. Venus and Jupiter will continue to shine, moving together [ http://SkyandTelescope.com/observing/objects/planets/article_572_4.asp ] until their closest approach on June 3. The Eiffel Tower [ http://www.tour-eiffel.fr/teiffel/uk/ ], however, is expected to remain right where it is.

Jupiter, its great Red Spot …

Name of Image	Jupiter, its great Red Spot three of its four largest satellites
Date of Image	1979-02-05
Full Description	On February 5, 1979, Voyager 1 made its closest approach to Jupiter since early 1974 and 1975 when Pioneers 10 and 11 made their voyages to Jupiter and beyond. Voyager 1 completed its Jupiter encounter in early April, after taking almost 19,000 pictures and recording many other scientific measurements. Although astronomers had studied Jupiter from Earth for several centuries, scientists were surprised by many of Voyager 1 and 2's findings. They now understand that important physical, geological, and atmospheric processes go on that they had never observed from Earth. Discovery of active volcanism on the satellite Io was probably the greatest surprise. It was the first time active volcanoes had been seen on another body in the solar system. Voyager also discovered a ring around Jupiter. Thus Jupiter joins Saturn, Uranus, and Neptune as a ringed planet -- although each ring system is unique and distinct from the others.

Voyager 2 Launch

title	Voyager 2 Launch
date	08.20.1977
description	Voyager 2 was launched August 20, 1977, sixteen days before Voyager 1 aboard a Titan-Centaur rocket. Their different flight trajectories caused Voyager 2 to arrive at Jupiter four months later than Voyager 1, thus explaining their numbering. The initial mission plan for Voyager 2 specified visits only to Jupiter and Saturn. The plan was augmented in 1981 to include a visit to Uranus, and again in 1985 to include a flyby of Neptune. After completing the tour of the outer planets in 1989, the Voyager spacecraft began exploring interstellar space. The Voyager mission has been managed by NASA's Office of Space Science and the Jet Propulsion Laboratory. Image Credit: NASA

Moon And Venus Share The Sky

Title	Moon And Venus Share The Sky
Explanation	July is drawing to a close and in the past few days, some early morning risers [ http://antwrp.gsfc.nasa.gov/apod/ap990714.html ] could have looked east and seen a crescent Moon sharing the pre-dawn [ http://science.nasa.gov/headlines/y2000/ast25jul_1m.htm ] skies with planets Jupiter and Saturn. Planet Mercury will also pass about 2 degrees from the thin waning crescent Moon [ http://aa.usno.navy.mil/AA/faq/docs/moon_phases.html ] just before sunrise near the eastern horizon on Saturday, July 29. And finally, on the evening of July 31st, Venus will take its turn near the crescent Moon [ http://antwrp.gsfc.nasa.gov/apod/ap991108.html ]. But this time it will be a day-old crescent Moon near the western horizon, shortly after sunset [ http://antwrp.gsfc.nasa.gov/apod/ap000507.html ]. In fact [ http://pages.prodigy.net/pam.orman/JoeAlmanac2000.html ], on July 31 (August 1 Universal Time) the Moon will occult [ http://www.skypub.com/sights/occultations/lunar/ 0001lunarocc.html ] (pass in front of) Venus for northwestern observers [ http://www.skypub.com/sights/images2000/ 0008moonvenus_big.jpg ] in North America. This telescopic picture taken on 31 December 1997, shows a lovely young crescent Moon and brilliant crescent Venus in [ http://antwrp.gsfc.nasa.gov/apod/ap990903.html ] the early evening sky near Bursa, Turkey [ http://www.mersina.com/Turkey/Marmara/Bursa/index.html ]. And what about the Sun? On Sunday, July 30, a partial eclipse of the Sun [ http://sunearth.gsfc.nasa.gov/eclipse/extra/ PSE2000Jul31.html ] will be visible from some locations [ http://sunearth.gsfc.nasa.gov/eclipse/OH/ PSE2000Jul.gif ] in North America.

Jupiter's Rings

Title	Jupiter's Rings
Explanation	Astronomers using NASA's Voyager [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft to search for a ring system around Jupiter discovered these faint rings in 1979. Unlike Saturn's bright rings which are composed of chunks of rock and ice, Jupiter's rings [ http://ringside.arc.nasa.gov/www/jupiter/jupiter.html ] appear to consist of fine particles of dust. One possibility is that the dust is produced by impacts with Jupiter's inner moons. This false color image has been computer enhanced. The gas giant planets, Jupiter, Saturn, Uranus, and Neptune are all known to have rings. For more information about planetary ring systems see the Planetary Rings Node [ http://ringside.arc.nasa.gov/ ]. Tomorrow's picture: A Volcanic Moon

Uranus' Ring System

Title	Uranus' Ring System
Explanation	The rings of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] are thin, narrow, and dark compared to other planetary ring systems. Brightened artificially by computer, the ring particles reflect as little light as charcoal, although they are really made of ice chucks darkened by rock. This false-color, infrared picture [ http://www.stsci.edu/pubinfo/PR/96/15/A.html ] from the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] taken in July 1995 shows the rings in conjunction to the planet. The infrared [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#infrared ] light allows one to see detail in different layers of Uranus' [ http://antwrp.gsfc.nasa.gov/apod/lib/uranus.html ] atmosphere, which has been digitally enhanced with false color. Three other planets in our Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap950819.html ] are known to have rings: Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap950802.html ], Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ], and Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]. Four of Uranus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/uranus.html ]' moons are visible outside the ring plane. The rings of Uranus [ http://ringside.arc.nasa.gov/www/uranus/uranus.html ] were discovered from ground-based observations in 1977.

Neptune - dark oval

PIA01990

Sol (our sun)

Imaging Science Subsystem - …

Title	Neptune - dark oval
Original Caption Released with Image	The large, dark oval spot in Neptune's atmosphere is just coming into view in this picture returned from the Voyager 2 spacecraft on June 30, 1989. The spacecraft was about 83 million kilometers (51.5 million miles) from Neptune. Voyager scientists are interested in the dark oval cloud system, a very large system similar to Jupiter's Great Red Spot. Contrast of the features in Neptune's atmosphere is similar to that obtained at Saturn at about this same distance and lighting, whereas the features are similar to those seen at Jupiter. The Jet Propulsion Laboratory manages the Voyager Project for NASA's Office of Space Science and Applications.

Voyager Tour Montage

Title	Voyager Tour Montage
Full Description	This montage of images of the planets visited by Voyager 2 was prepared from an assemblage of images taken by the Voyager 2 spacecraft. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California.
Date	08/01/1989
NASA Center	Jet Propulsion Laboratory

Description	Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn.
Full Description	The solar system's largest moon, Ganymede, is captured here alongside the planet Jupiter in a color picture taken by NASA's Cassini spacecraft on Dec. 3, 2000. Ganymede is larger than the planets Mercury and Pluto and Saturn's largest moon, Titan. Both Ganymede and Titan have greater surface area than the entire Eurasian continent on our planet. Cassini was 26.5 million kilometers (16.5 million miles) from Ganymede when this image was taken. The smallest visible features are about 160 kilometers (about 100 miles) across. The bright area near the south (bottom) of Ganymede is Osiris, a large, relatively new crater surrounded by bright icy material ejected by the impact which created it. Elsewhere, Ganymede displays dark terrains that NASA's Voyager and Galileo spacecraft have shown to be old and heavily cratered. The brighter terrains are younger and laced by grooves. Various kinds of grooved terrains have been seen on many icy moons in the solar system. These are believed to be the surface expressions of warm, pristine, water-rich materials that moved to the surface and froze. Ganymede has proven to be a fascinating world, the only moon known to have a magnetosphere, or magnetic environment, produced by a convecting metal core. The interaction of Ganymede's and Jupiter's magnetospheres may produce dazzling variations in the auroral glows in Ganymede's tenuous atmosphere of oxygen. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona For higher resolution, click here.

Terrestrial Planet Interiors

title	Terrestrial Planet Interiors
description	Mercury Mercury has an average density of 5430 kilograms per cubic meter, which is second only to Earth among all the planets. It is estimated that the planet Mercury, like Earth, has a ferrous core with a size equivalent to two-thirds to three-fourths that of the planet's overall radius. The core is believed to be composed of an iron-nickel alloy covered by a mantle and surface crust. Venus It is believed that the composition of the planet Venus is similar to that of Earth. The planet crust extends to around 10-30 kilometers below the surface, under which the mantle reaches to a depth of some 3000 kilometers. The planet core comprises a liquid iron-nickel alloy. Average planet density is 5240 kilograms per cubic meter. Earth The Earth comprises three separate layers: a crust, a mantle, and a core (in descending order from the surface). The crust thickness averages 30 kilometers for land masses and 5 kilometers for seabeds. The mantle extends from just below the crust to some 2900 kilometers deep. The core below the mantle begins at a depth of around 5100 kilometers, and comprises an outer core (liquid iron-nickel alloy) and inner core (solid iron-nickel alloy). The crust is composed mainly of granite in the case of land masses and basalt in the case of seabeds. The mantle is composed primarily of peridotite and high-pressure minerals. Average planet density is 5520 kilograms per cubic meter. Mars Mars is roughly one-half the diameter of Earth. Due to its small size, it is believed that the martian center has cooled. Geological structure is mainly rock and metal. The mantle below the crust comprises iron-oxide-rich silicate. The core is made up of an iron-nickel alloy and iron sulfide. Average planet density is 3930 kilograms per cubic meter. Pluto The structure of Pluto is not very well understood at present. Nevertheless, spectroscopic observation from Earth in the 1970s has revealed that the planet surface is covered with methane ice. Surface temperature is -230?C (-382?F), and the frozen methane exhibits a bright coloration. However, with the exception of the polar caps, the frozen methane surface is seen to change to a dark red when eclipsed by its moon Charon. Average planet density is 2060 kilograms per cubic meter. The low average density requires that the planet must be a mix of ice and rock. Image Credit: Lunar and Planetary Institute

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

Children of the Sun

Title	Children of the Sun
Explanation	For a moment [ http://photojournal.jpl.nasa.gov/index.html ], planets Jupiter [ http://kids.nineplanets.org/jupiter.htm ], Venus [ http://kids.nineplanets.org/venus.htm ], Mars [ http://kids.nineplanets.org/mars.htm ], and Mercury [ http://kids.nineplanets.org/mercury.htm ] all posed near their parent star in this Sun-centered view, recorded on November 11. The picture, from a coronograph onboard the space-based SOlar Heliospheric Observatory [ http://sohowww.nascom.nasa.gov/ ], spans 15 degrees with the Sun's size and position indicated by the white circle. Background stars are also visible as the otherwise overwhelming sunlight is blocked by the coronograph's [ http://lasco-www.nrl.navy.mil/index.php?p=content/ about_lasco ] occulting disk. But the planets themselves, in particular Jupiter and Venus, are still bright enough to cause significant horizontal streaks in the image. Mercury is actually moving most rapidly (left to right) through the field and days earlier [ http://sohowww.nascom.nasa.gov/hotshots/2006_11_06/ ] was seen to cross in front [ http://www.spaceweather.com/eclipses/gallery_08nov06.htm ] of the solar disk. So what's that bright double star to the left of Mars? Zubenelgenubi [ http://antwrp.gsfc.nasa.gov/apod/ap040514.html ], of course.

Moon and Planets Sky Credit & Copyright: Wojtek Rychlik [ http://www.pikespeakphoto.com ]

Moon and Planets Sky Credit …

Title	Moon and Planets Sky Credit & Copyright: Wojtek Rychlik [ http://www.pikespeakphoto.com ]
Explanation	Look up into the sky tonight [ http://science.nasa.gov/headlines/y2004/ 19mar_planets.htm ] and without a telescope or binoculars you might have a view [ http://astronomy.swin.edu.au/staff/gmackie/billions.html ] like this one of Moon, planets and stars. The lovely photo [ http://www.pikespeakphoto.com/planets.html ] was taken on March 23rd, and captures the crescent Moon on the horizon with Venus above it. Both brilliant celestial bodies are over-exposed. Farther above Venus is the tinted glow of Mars with the Pleiades star cluster just to the red planet's right. The V-shaped arrangement of stars [ http://antwrp.gsfc.nasa.gov/apod/ap040304.html ] to the left of Mars is the Hydaes star cluster. Bright red giant Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/ aldebaran.html ], not itself a member of the Hyades cluster, marks the top left of the V. During the next week [ http://www.griffithobs.org/planetsgather.html ], all five naked-eye planets, Mercury, Venus, Mars, Jupiter, and Saturn, along with the Moon will grace the evening sky [ http://skyandtelescope.com/observing/objects/planets/ article_1226_1.asp ] together - a lunar and planetary spectacle that can be enjoyed by skygazers [ http://www.spaceweather.com/ ] around the world. But look just after sunset, low on the western horizon, to see Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap030412.html ] before it sets. The next similar gathering [ http://antwrp.gsfc.nasa.gov/apod/ap000524.html ] of the planets will be in 2008.

An Atlas Centaur Rocket Laun …

Title	An Atlas Centaur Rocket Launches
Explanation	Atlas Centaur [ http://www.lerc.nasa.gov/Other_Groups/PAO/html/atlas2as.htm ] rockets have launched over 75 successful unmanned missions. These missions included the Surveyor [ http://antwrp.gsfc.nasa.gov/apod/ap951008.html ] series - the first vehicles to make soft landings on the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap950903.html ], Pioneer [ http://pyroeis.arc.nasa.gov/pioneer/PNhome.html ] 10 and 11 - the first missions to fly by Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap951206.html ] and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ] and the first man-made objects able to leave our Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap950819.html ], the Viking missions [ http://antwrp.gsfc.nasa.gov/apod/ap950721.html ] which landed on Mars [ http://antwrp.gsfc.nasa.gov/apod/ap950716.html ], several satellites in the High Energy Astrophysics Observatory [ http://heasarc.gsfc.nasa.gov/ ] (HEAO) series, Pioneer Venus [ http://nssdc.gsfc.nasa.gov/planetary/pioneer_venus.html ] which circled and mapped the surface of Venus [ http://antwrp.gsfc.nasa.gov/apod/ap950822.html ], and numerous Intelsat [ http://www.intelsat.int:8080/info/html/is5.html ] satellites. Of recent scientific interest was the Atlas [ http://www.ksc.nasa.gov/elv/ATLAS_CENTAUR/atlcent.htm ] launched SOHO [ http://sohowww.nascom.nasa.gov/index-text.html ] mission which will continually observe the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ]. Atlas rockets are manufactured by Lockheed Martin [ http://www.mmc.com/ ] Co.

Titania's Trenches

Title	Titania's Trenches
Explanation	British astronomer Sir William Herschel [ http://star.arm.ac.uk/history/herschel.html ] discovered Titania and Oberon in January of 1787. He wasn't reading Shakespeare's [ http://the-tech.mit.edu/Shakespeare/works.html ]"A Midsummer Night's Dream" though, he was making the first telescopic observations of moons of the planet Uranus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/uranus.html ] (a planet which he himself discovered in 1781 [ http://www-groups.dcs.st-and.ac.uk/~history/ HistTopics/Neptune_and_Pluto.html ]). In January of 1986, nearly 200 years later, NASA's robot explorer Voyager 2 became the only spacecraft to visit the remote Uranian [ http://antwrp.gsfc.nasa.gov/apod/ap990531.html ] system [ http://antwrp.gsfc.nasa.gov/apod/ap971103.html ]. Above is Voyager's highest resolution picture of Titania [ http://photojournal.jpl.nasa.gov/cgi-bin/ PIAGenCatalogPage.pl?PIA00039 ], Uranus' largest moon. The picture is a composite of two images recorded from a distance of 229,000 miles. The icy, rocky world [ http://antwrp.gsfc.nasa.gov/apod/ap960304.html ] is seen to be covered with impact craters. A prominent system of fault valleys, some nearly 1,000 miles long, is visible as trench-like features near the terminator (shadow line). Deposits of highly reflective material which may represent frost can be seen along the sun-facing valley walls. The large impact crater near the top, known as Gertrude [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/uranus/titacrat.html ], is about 180 miles across. At the bottom the 60 mile wide fault valley, Belmont Chasma [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/uranus/titachas.html ], cuts into crater Ursula. Titania itself [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/wall/titania.html ] is 1,000 miles in diameter.

March of the Planets

Title	March of the Planets
Explanation	This March stargazers [ http://www2.astronomy.com/astro/SkyEvents/Current/SkyEvents.html ] have been treated to eye-catching [ http://members.home.com/rmscott/gallery_space_sky01.html ] formations of bright planets [ http://antwrp.gsfc.nasa.gov/apod/ap990308.html ] in western evening skies. On March 3rd, looking toward a beautiful sunset from a beach on the Hawaiian [ http://www.mhpcc.edu/~erobello/homepage_ernie/ernie1.html ] isle of Maui, photographer Rick Scott recorded this fleeting, four-planet [ http://members.home.com/rmscott/space_sky01/ maui_4_planets_19990303.html ]"hockey stick" array. Mercury, closest to the horizon and immersed in fading sunlight, is easily visible between silhouetted clouds. To the left and up in the deepening blue is Jupiter with a brilliant Venus above and Saturn shining in the darkened sky near the top of the image. The planets are seen [ http://astrosun.tn.cornell.edu/courses/astro201/planet_view.htm ] to lie close to the ecliptic [ http://antwrp.gsfc.nasa.gov/apod/ap970927.html ] - the apparent path of the sun - which is nearly perpendicular to the horizon for Hawaiian latitudes [ http://leahi.kcc.hawaii.edu/org/pvs/pvs.html ] at this time of year.

Pluto: The Frozen Planet

Title	Pluto: The Frozen Planet
Explanation	The Hubble Space Telescope imaged [ http://www.ast.cam.ac.uk/HST/press/pluto.html ] Pluto and its moon Charon in 1994. Pluto [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/pluto.html ] is usually the most distant planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] but because of its elliptic orbit Pluto crossed inside of Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]'s orbit in 1979 and will cross back out again in 1999. Compared to the other planets, very little is known about Pluto. Pluto [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/pluto.html ] is smaller than any other planet and even smaller than several other planet's moons. From Pluto, the Sun is just a tiny point of light. Pluto [ http://dosxx.colorado.edu/plutohome.html ] is probably composed of frozen rock and ice, much like Neptune's moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ]. Pluto has not yet been visited by a spacecraft, but a mission [ http://www.jpl.nasa.gov/pluto/ ] is being planned for the next decade. Tomorrow's picture: Our Solar System from Voyager

Saturn and Earth Ready for Cosmic Game of Peekaboo

Saturn and Earth Ready for C …

Description	SOHO images show Saturn on the left moving toward the Sun
Full Description	Saturn has a date to keep with Earth and the Sun. Since the Cassini spacecraft is orbiting Saturn, it's tagging along. Once a year Saturn and Earth find themselves almost directly opposite each other with the Sun in between, an event called conjunction. This year, conjunction will occur on Aug. 7. NASA's Solar and Heliospheric Observatory, known as SOHO (http://sohowww.nascom.nasa.gov/), keeps close watch on the Sun. SOHO images show Saturn on the left moving toward the Sun, which is shielded from view but represented by a white circle in the image center. When Saturn emerges from conjunction, it will appear in SOHO images heading toward the right and away from Sun. As Earth and Saturn play peekaboo with each other, radio communications with Cassini get very noisy, so most of Cassini's science operations are temporarily suspended. "We'll still be in constant communication," says David Doody, Cassini flight operations lead, "and we'll see the quality degrading as it nears the Sun. The last high-rate science data playback, at 14,220 bits per second, will occur Aug. 4, after which Cassini switches to low-rate telemetry downlink, at 1896 bps." During conjunction, the mission switches gears. "Finally, a break," says Doody. "We know the spacecraft is safe, especially since it won't be doing lots of commanded science activities, instead just staring at Earth with its high gain antenna. We'll be carrying out radio science studies of the solar corona, using carrier signals coming down from Cassini to study the sun's extended, super-hot atmosphere. Meanwhile, the spacecraft team's radio communications engineers will watch how many out of 100 test commands sent each day are received aboard the spacecraft with the noisy Sun in the way.""We'll also be using this low-activity period to conduct an operational readiness test, realistic training using contrived problems, for many of the new members of the flight team," adds Doody. Cassini will resume returning high-rate science data on Aug. 10, when it is well past the Sun. Note for sky watchers: The first time that Saturn will be visible again to the unaided eye from here on Earth will be about two weeks after conjunction. On the morning of Aug. 20, Saturn will rise in the east an hour before the sun does. Early birds in the United States will be able to spot swift Mercury one degree above Saturn. The next morning, they can spot Mercury one degree to the lower left of the planet. On Aug. 26 and 27 Saturn pairs with much brighter Venus. To see the latest image from SOHO click here.
Date	August 3, 2006

Venus, Moon, and Neighbors

Title	Venus, Moon, and Neighbors
Explanation	Rising before the Sun on February 2nd, astrophotographer [ http://pages.prodigy.net/pam.orman/JoeGallery.html ] Joe Orman anticipated [ http://pages.prodigy.net/pam.orman/JoeAlmanac2000.html ] this apparition of the bright morning star [ http://ispec.scibernet.com/station/morn_star.html ] Venus near a lovely crescent Moon above a neighbor's house in suburban Phoenix, Arizona, USA. Fortunately, the alignment of bright planets and the Moon is one of the most inspiring sights in the night sky [ http://www.skypub.com/sights/skyevents/0004skyevents.html ] and one that is often easy to enjoy and share without any special equipment. Take tonight [ http://spacescience.com/headlines/y2000/ast30mar_1m.htm ], for example. Those blessed with clear skies can simply step outside near sunset and view a young crescent Moon very near three bright planets in the west Jupiter [ http://galileo.jpl.nasa.gov/ ], Mars [ http://mars.jpl.nasa.gov/mgs/ ], and Saturn [ http://www.jpl.nasa.gov/cassini/ ]. Jupiter will be the unmistakable brightest star near the Moon with a reddish Mars just to Jupiter's north and pale yellow Saturn directly above. Of course, these sky shows [ http://drumright.ossm.edu/astronomy/conjunctions.html ] create an evocative picture [ http://antwrp.gsfc.nasa.gov/apod/ap000310.html ] but the planets and Moon just appear to be near each other -- they are actually only approximately lined up and lie in widely separated orbits. Unfortunately, next month's highly publicized alignment of planets [ http://www.griffithobs.org/SkyAlignments.html ] on May 5th will be lost from view in the Sun's glare but such planetary alignments [ http://www.skypub.com/news/special/whypanic.html ] occur repeatedly and pose no danger [ http://www.badastronomy.com/bad/misc/planets.html ] to planet Earth.

Dr. Edward C. Stone

Dr. Stone was appointed Dire …

Description

Dr. Stone was appointed Director of the Jet Propulsion Laboratory on January 1, 1991. In this capacity he also serves as a Vice President of Caltech. Dr. Stone earned his associate of arts degree in 1956 from Burlington Junior College before continuing his studies at the University of Chicago. After receiving his master of science (1959) and Ph.D. (1964) degrees in physics, he joined Caltech as a research fellow in physics. Stone was subsequently appointed senior research fellow and assistant professor (1967), associate professor (1971), professor of physics (1976), chairman of Caltech's Division of Physics, Mathematics and Astronomy (1983 - 1988), and Vice President for Astronomical Facilities (1988 - 1990). Since his first cosmic-ray experiments on Discoverer satellites in 1961, Stone has been a principal investigator on nine NASA spacecraft missions and a co- investigator on five other NASA missions for which he developed high resolution instruments for measuring the isotopic and elemental composition of energetic cosmic-ray nuclei. Using these instruments, Stone and his colleagues undertook some of the first studies of the isotopic composition of three distinct samples of matter. The matter arrives at Earth as cosmic rays from nearby regions in our galaxy, as solar energetic particles from the Sun, and as the anomalous component from the local interstellar medium. These instruments also have been used for studies of planetary magnetospheres, including the discovery of energetic sulfur and oxygen ions from Jupiter's satellite, Io. Stone also jointly developed a large-area electronic satellite instrument for measuring the abundance of very rare heavy galactic cosmic-ray nuclei, such as lead and platinum, and collaborated in the development of an imaging gamma-ray telescope. Since 1972, Dr. Stone has served as the project scientist for the Voyager Mission, participating in both hardware development and mission operations. Following launch in 1977 of the twin Voyager spacecraft, he coordinated the efforts of 11 teams of scientists in their studies of Jupiter, Saturn, Uranus and Neptune. Among his many scientific awards and honors, Stone was a Sloan Foundation fellow and has received the NASA Exceptional Scientific Achievement Medal, the NASA Distinguished Service Medal, the American Institute of Aeronautics and Astronautics Dryden Medal and Space Science Award, and the NASA Distinguished Public Service Medal. He is the recipient of the NASA Outstanding Leadership Medal, the Aviation Week and Space Technology Aerospace Laurels Award, the National Space Club Science Award, the Association for Unmanned Vehicle Systems National Award for Operations, the National Medal of Science, the American Philosophical Society Magellanic Award, the American Academy of Achievement Golden Plate Award and the COSPAR Award for Outstanding Contribution to Space Science. He has received honorary degrees from Washington University, St. Louis, Harvard University, and the University of Chicago. Stone is a member of the National Academy of Sciences and the International Academy of Astronautics. He is a fellow of the American Physical Society, the American Geophysical Union, and the American Institute of Aeronautics and Astronautics. He is also a member of the American Astronomical Society, the International Astronomical Union and an honorary member of the Astronomical Society of the Pacific. #####

Dr. Edward C. Stone

Dr. Stone was appointed Dire …

Description

Dr. Stone was appointed Director of the Jet Propulsion Laboratory on January 1, 1991. In this capacity he also serves as a Vice President of Caltech. Dr. Stone earned his associate of arts degree in 1956 from Burlington Junior College before continuing his studies at the University of Chicago. After receiving his master of science (1959) and Ph.D. (1964) degrees in physics, he joined Caltech as a research fellow in physics. Stone was subsequently appointed senior research fellow and assistant professor (1967), associate professor (1971), professor of physics (1976), chairman of Caltech's Division of Physics, Mathematics and Astronomy (1983 - 1988), and Vice President for Astronomical Facilities (1988 - 1990). Since his first cosmic-ray experiments on Discoverer satellites in 1961, Stone has been a principal investigator on nine NASA spacecraft missions and a co- investigator on five other NASA missions for which he developed high resolution instruments for measuring the isotopic and elemental composition of energetic cosmic-ray nuclei. Using these instruments, Stone and his colleagues undertook some of the first studies of the isotopic composition of three distinct samples of matter. The matter arrives at Earth as cosmic rays from nearby regions in our galaxy, as solar energetic particles from the Sun, and as the anomalous component from the local interstellar medium. These instruments also have been used for studies of planetary magnetospheres, including the discovery of energetic sulfur and oxygen ions from Jupiter's satellite, Io. Stone also jointly developed a large-area electronic satellite instrument for measuring the abundance of very rare heavy galactic cosmic-ray nuclei, such as lead and platinum, and collaborated in the development of an imaging gamma-ray telescope. Since 1972, Dr. Stone has served as the project scientist for the Voyager Mission, participating in both hardware development and mission operations. Following launch in 1977 of the twin Voyager spacecraft, he coordinated the efforts of 11 teams of scientists in their studies of Jupiter, Saturn, Uranus and Neptune. Among his many scientific awards and honors, Stone was a Sloan Foundation fellow and has received the NASA Exceptional Scientific Achievement Medal, the NASA Distinguished Service Medal, the American Institute of Aeronautics and Astronautics Dryden Medal and Space Science Award, and the NASA Distinguished Public Service Medal. He is the recipient of the NASA Outstanding Leadership Medal, the Aviation Week and Space Technology Aerospace Laurels Award, the National Space Club Science Award, the Association for Unmanned Vehicle Systems National Award for Operations, the National Medal of Science, the American Philosophical Society Magellanic Award, the American Academy of Achievement Golden Plate Award and the COSPAR Award for Outstanding Contribution to Space Science. He has received honorary degrees from Washington University, St. Louis, Harvard University, and the University of Chicago. Stone is a member of the National Academy of Sciences and the International Academy of Astronautics. He is a fellow of the American Physical Society, the American Geophysical Union, and the American Institute of Aeronautics and Astronautics. He is also a member of the American Astronomical Society, the International Astronomical Union and an honorary member of the Astronomical Society of the Pacific. #####

Ganymede and Jupiter

PIA02862

Sol (our sun)

Imaging Science Subsystem

Title	Ganymede and Jupiter
Original Caption Released with Image	The solar system's largest moon, Ganymede, is captured here alongside the planet Jupiter in a color picture taken by NASA's Cassini spacecraft on Dec. 3, 2000. Ganymede is larger than the planets Mercury and Pluto and Saturn's largest moon, Titan. Both Ganymede and Titan have greater surface area than the entire Eurasian continent on our planet. Cassini was 26.5 million kilometers (16.5 million miles) from Ganymede when this image was taken. The smallest visible features are about 160 kilometers (about 100 miles) across. The bright area near the south (bottom) of Ganymede is Osiris, a large, relatively new crater surrounded by bright icy material ejected by the impact, which created it. Elsewhere, Ganymede displays dark terrains that NASA's Voyager and Galileo spacecraft have shown to be old and heavily cratered. The brighter terrains are younger and laced by grooves. Various kinds of grooved terrains have been seen on many icy moons in the solar system. These are believed to be the surface expressions of warm, pristine, water-rich materials that moved to the surface and froze. Ganymede has proven to be a fascinating world, the only moon known to have a magnetosphere, or magnetic environment, produced by a convecting metal core. The interaction of Ganymede's and Jupiter's magnetospheres may produce dazzling variations in the auroral glows in Ganymede's tenuous atmosphere of oxygen. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

Earth, Moon, and Jupiter, as seen from Mars

Earth, Moon, and Jupiter, as …

PIA04529

Sol (our sun)

Mars Orbiter Camera

Title	Earth, Moon, and Jupiter, as seen from Mars
Original Caption Released with Image	MGS MOC Release No. MOC2-368, 22 May 2003 What does Earth look like when viewed from Mars? At 13:00 GMT on 8 May 2003, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) had an opportunity to find out. In addition, a fortuitous alignment of Earth and Jupiter--the first planetary conjunction viewed from another planet--permitted the MOC to acquire an image of both of these bodies and their larger satellites. At the time, Mars and the orbiting camera were 139 million kilometers (86 million miles) from Earth and almost 1 billion kilometers (nearly 600 million miles) from Jupiter. The orbit diagram, from 24-bit color to 8-bit color using a JPEG to GIF conversion program. These 8-bit color images were converted to 8-bit grayscale and an associated lookup table mapping each gray value of that image to a red-green-blue color triplet (RGB). Each color triplet was root-sum-squared (RSS), and sorted in increasing RSS value. These sorted lists were brightness-to-color maps for their respective images. Each brightness-to-color map was then used to convert the 8-bit grayscale MOC image to an 8-bit color image. This 8-bit color image was then converted to a 24-bit color image. The color image was edited to return the background to black. Three separate color tables were used: one each for the Earth, Moon and Jupiter. Jupiter's Galilean Satellites were not colored. To view images separately, see: Earth and Jupiter as viewed from Mars PIA04530 [ http://photojournal.jpl.nasa.gov/catalog/PIA04530 ], Earth and Moon as viewed from Mars PIA04531 [ http://photojournal.jpl.nasa.gov/catalog/PIA04531 ], Jupiter and its Galilean Satellites as viewed from Mars PIA04532 [ http://photojournal.jpl.nasa.gov/catalog/PIA04532 ]., shows the geometry at the time the images were obtained. Because Jupiter is over 5 times farther from the Sun than Earth, two different exposures were needed to image the two planets. The images are shown mosaiced together. The composite has been highly contrast-enhanced and "colorized" to show both planets and their satellites. The MGS MOC high resolution camera only takes grayscale (black-and-white) images, the color was derived from Mariner 10 and Cassini pictures of Earth/Moon and Jupiter, respectively, as described in the note below. Earth/Moon: This is the first image of Earth ever taken from another planet that actually shows our home as a planetary disk. Because Earth and the Moon are closer to the Sun than Mars, they exhibit phases, just as the Moon, Venus, and Mercury do when viewed from Earth. As seen from Mars by MGS on 8 May 2003 at 13:00 GMT (6:00 AM PDT), Earth and the Moon appeared in the evening sky. The MOC Earth/Moon image has been specially processed to allow both Earth (with an apparent magnitude of -2.5) and the much darker Moon (with an apparent magnitude of +0.9) to be visible together. The bright area at the top of the image of Earth is cloud cover over central and eastern North America. Below that, a darker area includes Central America and the Gulf of Mexico. The bright feature near the center-right of the crescent Earth consists of clouds over northern South America. The image also shows the Earth-facing hemisphere of the Moon, since the Moon was on the far side of Earth as viewed from Mars. The slightly lighter tone of the lower portion of the image of the Moon results from the large and conspicuous ray system associated with the crater Tycho. Jupiter/Galilean Satellites: When Galileo first turned his telescope toward Jupiter four centuries ago, he saw that the giant planet had four large satellites, or moons. These, the largest of dozens of moons that orbit Jupiter, later became known as the Galilean satellites. The larger two, Callisto and Ganymede, are roughly the size of the planet Mercury, the smallest, Io and Europa, are approximately the size of Earth's Moon. This MGS MOC image, obtained from Mars orbit on 8 May 2003, shows Jupiter and three of the four Galilean satellites: Callisto, Ganymede, and Europa. At the time, Io was behind Jupiter as seen from Mars, and Jupiter's giant red spot had rotated out of view. This image has been specially processed to show both Jupiter and its satellites, since Jupiter, at an apparent magnitude of -1.8, was much brighter than the three satellites. A note about the coloring process: The MGS MOC high resolution camera only takes grayscale (black-and-white) images. To "colorize" the image, a Mariner 10 Earth/Moon image taken in 1973 was used to color the MOC Earth and Moon picture, and a recent Cassini image acquired during its Jupiter flyby was used to color the MOC Jupiter picture. The procedure used was as follows: the Mariner 10 and Cassini color images were converted

Earth, Moon, and Jupiter, as …

PIA04529

Sol (our sun)

Mars Orbiter Camera

Title	Earth, Moon, and Jupiter, as seen from Mars
Original Caption Released with Image	MGS MOC Release No. MOC2-368, 22 May 2003 What does Earth look like when viewed from Mars? At 13:00 GMT on 8 May 2003, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) had an opportunity to find out. In addition, a fortuitous alignment of Earth and Jupiter--the first planetary conjunction viewed from another planet--permitted the MOC to acquire an image of both of these bodies and their larger satellites. At the time, Mars and the orbiting camera were 139 million kilometers (86 million miles) from Earth and almost 1 billion kilometers (nearly 600 million miles) from Jupiter. The orbit diagram, from 24-bit color to 8-bit color using a JPEG to GIF conversion program. These 8-bit color images were converted to 8-bit grayscale and an associated lookup table mapping each gray value of that image to a red-green-blue color triplet (RGB). Each color triplet was root-sum-squared (RSS), and sorted in increasing RSS value. These sorted lists were brightness-to-color maps for their respective images. Each brightness-to-color map was then used to convert the 8-bit grayscale MOC image to an 8-bit color image. This 8-bit color image was then converted to a 24-bit color image. The color image was edited to return the background to black. Three separate color tables were used: one each for the Earth, Moon and Jupiter. Jupiter's Galilean Satellites were not colored. To view images separately, see: Earth and Jupiter as viewed from Mars PIA04530 [ http://photojournal.jpl.nasa.gov/catalog/PIA04530 ], Earth and Moon as viewed from Mars PIA04531 [ http://photojournal.jpl.nasa.gov/catalog/PIA04531 ], Jupiter and its Galilean Satellites as viewed from Mars PIA04532 [ http://photojournal.jpl.nasa.gov/catalog/PIA04532 ]., shows the geometry at the time the images were obtained. Because Jupiter is over 5 times farther from the Sun than Earth, two different exposures were needed to image the two planets. The images are shown mosaiced together. The composite has been highly contrast-enhanced and "colorized" to show both planets and their satellites. The MGS MOC high resolution camera only takes grayscale (black-and-white) images, the color was derived from Mariner 10 and Cassini pictures of Earth/Moon and Jupiter, respectively, as described in the note below. Earth/Moon: This is the first image of Earth ever taken from another planet that actually shows our home as a planetary disk. Because Earth and the Moon are closer to the Sun than Mars, they exhibit phases, just as the Moon, Venus, and Mercury do when viewed from Earth. As seen from Mars by MGS on 8 May 2003 at 13:00 GMT (6:00 AM PDT), Earth and the Moon appeared in the evening sky. The MOC Earth/Moon image has been specially processed to allow both Earth (with an apparent magnitude of -2.5) and the much darker Moon (with an apparent magnitude of +0.9) to be visible together. The bright area at the top of the image of Earth is cloud cover over central and eastern North America. Below that, a darker area includes Central America and the Gulf of Mexico. The bright feature near the center-right of the crescent Earth consists of clouds over northern South America. The image also shows the Earth-facing hemisphere of the Moon, since the Moon was on the far side of Earth as viewed from Mars. The slightly lighter tone of the lower portion of the image of the Moon results from the large and conspicuous ray system associated with the crater Tycho. Jupiter/Galilean Satellites: When Galileo first turned his telescope toward Jupiter four centuries ago, he saw that the giant planet had four large satellites, or moons. These, the largest of dozens of moons that orbit Jupiter, later became known as the Galilean satellites. The larger two, Callisto and Ganymede, are roughly the size of the planet Mercury, the smallest, Io and Europa, are approximately the size of Earth's Moon. This MGS MOC image, obtained from Mars orbit on 8 May 2003, shows Jupiter and three of the four Galilean satellites: Callisto, Ganymede, and Europa. At the time, Io was behind Jupiter as seen from Mars, and Jupiter's giant red spot had rotated out of view. This image has been specially processed to show both Jupiter and its satellites, since Jupiter, at an apparent magnitude of -1.8, was much brighter than the three satellites. A note about the coloring process: The MGS MOC high resolution camera only takes grayscale (black-and-white) images. To "colorize" the image, a Mariner 10 Earth/Moon image taken in 1973 was used to color the MOC Earth and Moon picture, and a recent Cassini image acquired during its Jupiter flyby was used to color the MOC Jupiter picture. The procedure used was as follows: the Mariner 10 and Cassini color images were converted

Hubble Provides a Moving Look at Neptune's Stormy Disposition

Hubble Provides a Moving Loo …

Title	Hubble Provides a Moving Look at Neptune's Stormy Disposition

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

The Colorful Lives of the Ou …

Title	The Colorful Lives of the Outer Planets

It's a Rocky World

Title	It's a Rocky World
Description	This artist's concept show a massive asteroid belt in orbit around a star the same age and size as our Sun. Evidence for this possible belt was discovered by NASA's Spitzer Space Telescope when it spotted warm dust around the star, presumably from asteroids smashing together. The view is from outside the belt, where planets like the one shown in the foreground, might possibly reside. A collision between two asteroids is depicted to the right. Collisions like this replenish the dust in the asteroid belt, making it detectable to Spitzer. The alien belt circles a faint, nearby star called HD 69830 located 41 light-years away in the constellation Puppis. Compared to our own solar system's asteroid belt, this one is larger and closer to its star -- it is 25 times as massive, and lies just inside an orbit equivalent to that of Venus. Our asteroid belt circles between the orbits of Mars and Jupiter. Because Jupiter acts as an outer wall to our asteroid belt, shepherding its debris into a series of bands, it is possible that an unseen planet is likewise marshalling this belt's rubble. Previous observations using the radial velocity technique did not locate any large gas giant planets, indicating that any planets present in this system would have to be the size of Saturn or smaller. Asteroids are chunks of rock from "failed" planets, which never managed to coalesce into full-sized planets. Asteroid belts can be thought of as construction sites that accompany the building of rocky planets.

Band of Rubble

Title	Band of Rubble
Description	This artist's animation illustrates a massive asteroid belt in orbit around a star the same age and size as our Sun. Evidence for this possible belt was discovered by NASA's Spitzer Space Telescope when it spotted warm dust around the star, presumably from asteroids smashing together. The view starts from outside the belt, where planets like the one shown here might possibly reside, then moves into to the dusty belt itself. A collision between two asteroids is depicted near the end of the movie. Collisions like this replenish the dust in the asteroid belt, making it detectable to Spitzer. The alien belt circles a faint, nearby star called HD 69830 located 41 light-years away in the constellation Puppis. Compared to our own solar system's asteroid belt, this one is larger and closer to its star -- it is 25 times as massive, and lies just inside an orbit equivalent to that of Venus. Our asteroid belt circles between the orbits of Mars and Jupiter. Because Jupiter acts as an outer wall to our asteroid belt, shepherding its debris into a series of bands, it is possible that an unseen planet is likewise marshalling this belt's rubble. Previous observations using the radial velocity technique did not locate any large gas giant planets, indicating that any planets present in this system would have to be the size of Saturn or smaller. Asteroids are chunks of rock from "failed" planets, which never managed to coalesce into full-sized planets. Asteroid belts can be thought of as construction sites that accompany the building of rocky planets.

Venus: Earth's Cloudy Twin Credit: Galileo [ http://galileo.jpl.nasa.gov/ ] Spacecraft, JPL [ http://www.jpl.nasa.gov/ ], NASA [ http://www.nasa.gov/ ];

Venus: Earth's Cloudy Twin C …

Title	Venus: Earth's Cloudy Twin Credit: Galileo [ http://galileo.jpl.nasa.gov/ ] Spacecraft, JPL [ http://www.jpl.nasa.gov/ ], NASA [ http://www.nasa.gov/ ];
Explanation	This picture by the Galileo spacecraft [ http://nssdc.gsfc.nasa.gov/planetary/galileo.html ] shows just how cloudy Venus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/venus.html ] is. Venus [ http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=34067 ] is very similar to Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ] in size and mass - and so is sometimes referred to as Earth's sister planet - but Venus [ http://pds.jpl.nasa.gov/planets/welcome/venus.htm ] has a quite different climate. Venus [ http://spacelink.nasa.gov/NASA.Projects/Space.Science/Solar.System/Pioneer.Venus/Venus.Discoveries ]' thick clouds and closeness to the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap980830.html ] (only Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap010819.html ] is closer) make it the hottest planet - much hotter than the Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ]. Humans could not survive there, and no life of any sort has ever been found. When Venus is visible [ http://www.space.com/spacewatch/venus_guide_031024.html ] it is usually the brightest object in the sky after the Sun and the Moon [ http://antwrp.gsfc.nasa.gov/apod/moon.html ]. More than 20 spacecraft have visited Venus [ http://nssdc.gsfc.nasa.gov/photo_gallery/PhotoGallery-Venus.html ] including Venera 9 [ http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1975-050D ], which landed on the surface, and Magellan [ http://www.jpl.nasa.gov/magellan/ ], which used radar to peer through the clouds and make a map of the surface [ http://antwrp.gsfc.nasa.gov/apod/ap030427.html ]. This visible light picture of Venus [ http://antwrp.gsfc.nasa.gov/apod/venus.html ] was taken by the Galileo spacecraft [ http://antwrp.gsfc.nasa.gov/apod/ap951206.html ] that orbited Jupiter from 1995 to 2003. Many things about Venus remain unknown, including the cause of mysterious bursts of radio waves [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995JATP...57..557S ].

Description	Titan's Relative Size
Full Description	Terrestrial planets (shown in the top row) are compared with the Solar System's largest satellites. Titan is the second-largest satellite in the solar system. Only Jupiter¿s satellite Ganymede is larger in diameter. Titan is actually larger than the planet Mercury and is almost as large as Mars. For higher resolution, click here.

Flight Over Venus

Now that humans have mastere …

3/4/08

Description	Now that humans have mastered atmospheric flight above the Earth, researchers at Glenn have set their sights on flight above our neighboring planets. Venus provides several advantages for flying a solar-powered aircraft. At the top of the cloud level, the solar intensity is comparable to or greater than solar intensities above Earth. The atmospheric pressure would make flight much easier than on planets such as Mars. In addition, Venus' slow rotation would allow an airplane to fly in continuous sunlight, eliminating the need for energy storage for nighttime flight. These factors make Venus a prime choice for a long-duration solar-powered aircraft for scientific research. Exploratory planetary mapping and atmospheric sampling over Venus may lead to a greater understanding of the greenhouse effect not only on Venus but on Earth as well. digital art by Les Bossinas (InDyne, Inc.), 2001
Date	3/4/08

Martian Moons Transit the Su …

The upper-left of these imag …

6/9/08

Description	The upper-left of these images shows the passing, or transit, of the Martian moon Deimos across the sun. This event is similar to solar eclipses seen from Earth in which our moon crosses in front of the sun. The bottom three images show Phobos, Mars's other moon, transiting the sun. The potato-shaped Phobos is roughly 15 miles across, about twice the size of Deimos. Deimos appears so much smaller because it is also a bit more than twice as far away from Mars as Phobos is. The Mars Exploration Rover Opportunity took images of both moons on different days in March 2004. Image credit: NASA/JPL/Cornell
Date	6/9/08

A Double Conjunction Eclipse

Title	A Double Conjunction Eclipse
Explanation	The crescent Moon [ http://www.seds.org/nineplanets/nineplanets/luna.html ], Venus [ http://www.hawastsoc.org/solar/eng/venus.htm ], and Jupiter [ http://pds.jpl.nasa.gov/planets/welcome/jupiter.htm ] all appeared together in the early morning hours of April 23rd. Some locations on Earth [ http://ceps.nasm.edu:2020/RPIF/EARTH/earth.html ] were able to witness [ http://www.staigerland.com/live/astrocam/ ] a rare double conjunction [ http://www.oregano.demon.co.uk/terms.htm#conjunc ] eclipse, where the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap980129.html ] occulted both Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap980202.html ] and Venus [ http://antwrp.gsfc.nasa.gov/apod/ap970603.html ] at the same time. The next [ http://www.skypub.com/news/news.shtml ] double conjunction eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap970924.html ] will involve Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap971130.html ] and Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ] and will occur on February 13, 2056.

A Western Sky at Twilight

Title	A Western Sky at Twilight
Explanation	On April 23rd, the Moon along with planets Saturn, Mars, and Venus (and planet Earth of course ...) were all visible [ http://science.nasa.gov/headlines/y2004/ 21apr_planets2.htm ] in the west at twilight, captured here [ http://www.nightskyevents.com/ ] from a site near Saylorvillle Lake north of Des Moines, Iowa, USA. Putting your cursor [ http://www.fourmilab.ch/yoursky/ ] over the image will label our fellow solar system wanderers [ http://liftoff.msfc.nasa.gov/academy/time/ weekdays.html ] and also reveal the approximate trajectory of the ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap001014.html ] - defined by Earth's orbit around the Sun - angling above the western horizon. After sunset tonight, the western sky will present a similar arrangement of planets, although the Moon will have moved east out of the picture, passing bright Jupiter along the ecliptic and heading for May 4th's total lunar eclipse [ http://www.xs4all.nl/~carlkop/eclipsmaan/leclips2004.html ]. May could also [ http://skyandtelescope.com/observing/objects/comets/ article_1238_1.asp ] be a good month for comets [ http://skyandtelescope.com/observing/objects/comets/ article_1229_2.asp ].

Pleiades, Planets, And Hot P …

Title	Pleiades, Planets, And Hot Plasma
Explanation	Bright stars of the Pleiades, four planets, and erupting solar plasma are all captured in this spectacular image [ http://sohowww.nascom.nasa.gov/hotshots/ ] from the space-based SOlar and Heliospheric Observatory (SOHO). In the foreground of the 15 degree wide field of view, a bubble of hot plasma, called a Coronal Mass Ejection (CME [ http://antwrp.gsfc.nasa.gov/apod/ap000309.html ]), is blasting away from the active Sun [ http://www.spaceweather.com/ ] whose position and relative size is indicated by the central white circle. Beyond [ http://sohowww.nascom.nasa.gov/hotshots/2000_05_03/ diagram1.jpg ] appear four of the five [ http://antwrp.gsfc.nasa.gov/apod/ap000505.html ] naked-eye planets [ http://sse.jpl.nasa.gov/features/planets/ planetsfeat.html ] -- courtesy [ http://www.badastronomy.com/bad/misc/planets.html ] of the planetary alignment [ http://science.nasa.gov/headlines/y2000/ ast30mar_1m.htm#alignments ] which did not destroy the world! In the background are distant stars and the famous Pleiades [ http://www.seds.org/messier/m/m045.html ] star cluster, also easily visible to the unaided eye when it shines in the night sky [ http://antwrp.gsfc.nasa.gov/apod/ap000504.html ]. Distances for these familiar [ http://www.seds.org/nineplanets/nineplanets/ nineplanets.html ] celestial objects are, the Sun [ http://helios.gsfc.nasa.gov/sun.html ], 150 million kilometers away, Mercury, Venus, Jupiter, and Saturn, about 58, 110, 780, and 1,400 million kilometers beyond the Sun respectively, and the Pleiades [ http://www.ras.ucalgary.ca/~gibson/pleiades/ ] star cluster at a mere 3,800 trillion kilometers (400 light-years). SOHO itself orbits 1.5 million kilometers sunward of planet Earth. The image [ http://sohowww.nascom.nasa.gov/data/latestimages.html ] was recorded by the Large Angle and Spectrometric COronagraph (LASCO) instrument on board SOHO on Monday, May 15 at 10:42 UT.

Hubble Discovers Dark Cloud in the Atmosphere of Uranus

Hubble Discovers Dark Cloud …

Title	Hubble Discovers Dark Cloud in the Atmosphere of Uranus

Three Planets by the Sea

Title	Three Planets by the Sea
Explanation	On Tuesday, June 28th, the setting Sun flooded the horizon with a beautiful warm light in this view from [ http://homepages.picknowl.com.au/sparda/ NEW/Newall.htm ] the beach beside the pier at Brighton in Adelaide, South Australia [ http://www.nla.gov.au/ ]. The Sun also illuminated three planets gathered in the western sky [ http://antwrp.gsfc.nasa.gov/apod/ap050624.html ], Mercury, Venus, and Saturn. From this perspective Mercury [ http://www.fourmilab.ch/images/3planets/ elongation.html ] is at the highest point in the celestial triangle, brilliant Venus [ http://www.fourmilab.ch/images/venus_daytime/ ] is just below, and Saturn stands farther to the left and below the close pair [ http://www.alpheratz.net/observing/ VenusMercuryAppulse_2005-06-27/ ]. Of course, the planets only appear close together on the sky but are actually quite far apart in space. The orbits [ http://www.fourmilab.ch/cgi-bin/uncgi/ Solar/action?sys=-Sf ] of Mercury and Venus are both interior to Earth's orbit, while gas giant Saturn [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ saturnfact.html ] lies in the outer solar system, over nine astronomical units [ http://neo.jpl.nasa.gov/glossary/au.html ] from the Sun. Late next week [ http://skyandtelescope.com/observing/ataglance/ article_110_1.asp ], Venus and Mercury will share western skies with the young crescent Moon [ http://antwrp.gsfc.nasa.gov/apod/ap050513.html ].

Rounding the Corner

Description	Rounding the Corner
Full Description	+ View Movie A movie sequence of Saturn's G ring over a full orbital revolution captures its single bright arc on the ring's inner edge. The movie is composed of 70 individual narrow-angle camera images taken during a period of just over 20 hours while Cassini stared at the ring. The orbital period for particles in the center of the G ring is about 19.6 hours. At the beginning of the sequence, the ring arc, a site of concentrated ring particles, is seen rounding the ring edge. The arc orbits at a distance of 167,496 kilometers (104,080 miles). It is about 250 kilometers (155 miles) wide in radius and subtends less than 60 degrees of orbital longitude. The classical position of the G ring is about 172,600 kilometers (107,250 miles) from Saturn, and the arc blends smoothly into this region. Scientists suspect that bodies trapped in this remarkably bright feature may be the source of the G ring material, driven outward from the arc by electromagnetic forces in the Saturn system. The arc itself is likely held in place by gravitational resonances with Mimas of the type that anchor the famed arcs in Neptune's rings. There is an obvious narrow dark gap in the G ring beyond the arc. This feature is close to yet another resonance with Mimas, but no arcs are present at this locale. This view looks toward the unlit side of the rings from about 10 degrees above the ringplane. Imaging artifacts jitter within the scene, a result of the high phase angle and faintness of the G ring. Stars slide across the background from upper left to lower right. The images in this movie were taken on Sept. 19 and 20 at a distance of approximately 2.1 to 2.2 million kilometers (1.3 to 1.4 million miles) from Saturn and at a Sun-G ring-spacecraft, or phase, angle that ranged from 167 to 164 degrees. Image scale is about 13 kilometers (8 miles) per pixel in the radial (outward from Saturn) direction. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute
Date	October 11, 2006

Hands-On Book of Hubble Images Allows the Visually Impaired to "Touch the Universe

Hands-On Book of Hubble Imag …

Title	Hands-On Book of Hubble Images Allows the Visually Impaired to "Touch the Universe

Saturn IVB

An expended Saturn IVB stage …

5/5/09

Description	An expended Saturn IVB stage was being used as a target for simulated docking maneuvers over Sonora, Mexico, during Apollo 7's second revolution around Earth on Oct. 11, 1968. Image Credit: NASA
Date	5/5/09

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