As we gathered images for Planetary Taxi we found that some of the images came with a great deal of information while others came with very little. In some cases we asked experts like Paul Doherty at the Exploratorium in San Francisco or Peter Saxby, a former Physics teacher, to add information.
The following are the captions for the pictures as they appear in the Planet Information in Planetary Taxi. In addition there is extra information in the unnumbered paragraphs after many of the numbered images. The planets are arranged in order from the Sun to Pluto.
The document is very long. You may want to just cut and paste parts of it into other documents.
For more resources on information regarding the images, see the README document on the Planetary Taxi CD.
SUN
1. Here is an X-ray view of the Sun. The bright spots are super hot spots with temperatures hundreds of thousands of degrees—hot enough to emit X-rays themselves.
The Ulysses spacecraft was launched from the Space Shuttle Discovery in October 1990. Its mission is to explore the Sun’s polar regions, areas that are inaccessible to Earth-based observers. Ulysses will cross the Sun’s equator in February 1995. A payload of nine instruments will study magnetic fields in space, particles streaming from the Sun that constitute the solar wind, X-rays and energetic particles from solar flares, cosmic rays from interstellar space, cosmic dust and solar radio emissions. Ulysses is a joint mission of NASA and the European Space Agency (ESA).
2. Here is a solar flare on the Sun. It takes 8.5 minutes for light from the Sun to reach Earth, but it takes three days for particles from the solar flare to reach Earth. These particles create auroras on Earth.
Some of the complex activity of the Sun can be seen in this image, captured by a telescope on board NASA’s Skylab orbiting space station August 9, 1973. Taken in ultraviolet light, it shows details of the chromosphere, a layer of gas in the outer part of the Sun’s atmosphere. Above the disk of the Sun is a giant, flame[like solar prominence; its twisting shape follows the outlines of magnetic fields. At this scale, Earth would be smaller than the black dot near the base of the prominence, which extends 600,000 km (373,000 mi).
3. Very hot gasses follow the magnetic field lines on the Sun and leap out to create solar flares.
4. This is the early stage of a solar eclipse seen from Earth. The Moon is just beginning to pass in front of the Sun.
5. A solar eclipse is in progress. Earth’s Moon is blocking a portion of the Sun from view.
6. Total solar eclipse. The Moon is blocking out the Sun. Thus, the Earth is in the Moon’s shadow.
7. Ulysses, a joint project between the United States and Europe, will carry nine instruments to conduct experiments at the polar regions of the Sun and in interstellar space never before explored.
8. Solar telescope at Kitt Peak National Observatory in Arizona. A mirror tracks the Sun. The beam of light is reflected down the sloping portion of the structure to instruments which collect data.
Solar telescope at Kitt Peak National Observatory. Established in 1958 on the Papago Indian Reservation in Arizona, the observatory has the largest telescope ever designed for solar observation, as well as a vacuum tower telescope used for solar research. At the top of the tower is a large mirror which tracks the sun. The beam of light is reflected down the long sloping portion of the structure to instruments which analyze the data.
9. Asteroids are smaller than planets. They also orbit the Sun. This image of Gaspra, taken by the Galileo spacecraft, is our first true image of a member of the asteroid belt between Mars and Jupiter.
MERCURY
1. Mercury, the first planet out from the Sun, is completely covered with craters. That means that it’s a very old planet. The brighter areas are fresher impacts.
Planet Mercury. MERCURY • Mean distance from Sun: 0.387 AU • Period of revolution: 88.0 d • Period of rotation: 58.7 d • Equatorial radius: 0.382 times Earth’s • Mass: 0.532 times Earth’s • Density: 5.4 g/cc • Surface gravity: 0.377 times Earth’s • Escape velocity from surface: 4.17 km/sec • Daytime temperature: 430°C, 800°F • Nighttime temperature: -170°C, 280°F • Atmosphere (main components): H2, He from solar wind • Atmospheric pressure: 1 E -15 atm • Axis tilt: 0° • Eccentricity: 0.206 • Inclination of orbit: 7.00° • Synchronous orbit radius for satellite: 237,000 km • Number of known satellites: None • First observed: Ancient times • Explorations: Mariner (1974-1975)
2. Mercury was photographed by Mariner10, the only spacecraft to visit the planet. Daytime temperatures are extremely hot, while nighttime temperatures are much colder than on Earth.
The bright-rayed crater Kuiper (named for astronomer Gerard P. Kuiper) can be seen just above center on the planet’s illuminated side. The landscape is dominated by large craters and basins, with extensive plains between the craters. As the planet closest to the sun Mercury’s surface is baked by high temperatures on its sunlit side and frozen during the long Mercury night, which is the equivalent of 88 Earth days. Mercury has no appreciable atmosphere.
3. This picture of Mercury taken by Mariner 10 shows a part of the planet called “weird terrain.”
4. Here is the Caloris Basin on Mercury. The basin was probably formed by the impact of a large body in the early history of Mercury.
5. Discovery Rupes on Mercury. Rupes are ridges or cliffs on planetary surfaces.
6. Mariner 10 photographed this double-ringed crater on Mercury. The spacecraft provided the first close-up views of Mercury.
VENUS
1. A view of Venus from the Magellan spacecraft. Magellan looked through the clouds of Venus with radar. Normally, you cannot see the terrain of Venus because it is completely covered with clouds.
The bright band across the center of the image is Aphrodite Terra, an elevated region. To the right of center is Maat Mons. With an 8-kilometer (5-mile) summit, Maat is the highest volcano on the planet. The large circular feature at the lower left is Artemis Chasma, a trogh with walls as high as 2 kilometers (1.2 miles). Several smooth (dark in radar images) patches associated with impact craters can be seen in the northern hemisphere.
This false-colored, computer generated image of Venus is based on data
gathered by the Magellan spacecraft. The simulated color is based on color
images from the Soviet Venera 13 and 14 spacecraft.
2. Ultraviolet view of Venus. Venus is completely covered by clouds. Both dark and light areas of the picture are clouds. The clouds flow from east to west at about 230 mph.
The dark sulfuric acid clouds contrast with lighter clouds of carbon dioxide.
Venus’ clouds are transparent to Magellan’s Synthetic aperture radar (SAR). The SAR can penetrate the thick cloud cover that perpetually shields the surface of Venus. The radar sensor acts like a complex camera with its own flash. Radar energy is “flashed” to the surface from the spacecraft, which then electronically records the returning echo. The rougher the terrain, the brighter its appearance. Smooth surface areas appear dark because they scatter the radar energy away and little or no energy returns to the spacecraft.
3. This is an enhanced view of Venus, the way it looks with normal light. Very little detail can be seen.
4. Here is a false-color image of the northern hemisphere of Venus, created from radar measurements. The poles appear smooth because of missing information.
5. This is an older image of Venus made from Pioneer’s radar. It shows the southern hemisphere. Colors are used to show height. The circle at the bottom is where there was no data to fill in the picture.
6. This photograph of Venus in ultraviolet is from the Pioneer spacecraft’s 1978 mission to Venus.
7. This spacecraft photo of Venus is enhanced to show cloud formations.
8. Venus and its cloud formations.
9. An artist’s vision of what the Pioneer bus looks like in the upper atmosphere of Venus.
10. This is an artist’s vision of the Pioneer probe on the surface of Venus.
11. Diagram of the atmosphere on Venus.
12. Wind patterns on Venus.
13. Looking back at Venus.
14.. The spacecraft Magellan has its solar panels pointed toward the Sun. In this image, Magellan is slowly orbiting towards the north pole of Venus.
15. This drawing shows the Magellan spacecraft in an elliptical orbit around Venus. Magellan is in the mapping and data transmission phase of its mission.
16. A plateau area named Lakshimi Planum. On the horizon is a mountain called Danu Montes. The dark spots are areas not covered by Magellan’s radar.
17. This Magellan image of Freyja Montes shows us the fractured dome called “Turtle-Back.”
18. A rare image of three impact craters in Lavinia Planitia. Most impact craters on Venus have been destroyed by volcanos and lava flows.
19. Aurelia is one of the few impact craters on Venus.
20. These seven mounds are called pancake domes. They are filled with lava — not syrup. (too bad!) The lava has come up from inside Venus.
21. This photo shows a twisted volcanic channel on Venus.
22. This Magellan image of Venus shows us gridded plains that are up to 37 kilometers wide, (about 23 miles).
23. A computer generated this image of the volcano Sif Mons on Venus. The spacecraft Magellan collected radar images during its mission to map the surface of Venus.
24. This is a dark halo impact crater in Lavinia on the surface of Venus.
EARTH
1. Earth from the Galileo spacecraft. This image offers a great view of Antarctica and South America. You can see the spirals and storm systems encircling Antarctica.
2. Here is the planet Earth, from space.
3. A sideways view of Earth.
4. This view of Earth shows the continent of Africa and the Arabian Peninsula. Antarctica is visible through the clouds, to the right.
5. The Shuttle Imaging Radar flies in the space shuttle cargo bay. It has the power to collect data over any type of region, regardless of sunlight or weather.
6. ATMOS (Atmospheric Trace Molecule Spectroscopy) is used to decide what the many layers of the Earth’s atmosphere are made of.
7. A hurricane on Earth as seen from orbit.
8. Earth rise over the Moon. It’s interesting to see our planet from the Moon’s point of view.
9. The Earth rises over the Moon. From Earth, we see phases of the Moon. From the Moon, we would see phases of the Earth.
10. Earth rise over the Moon. Notice that in this picture from the Moon, you can imagine a “Human in the Earth.”
11. Earth rise over the Moon. We see a quarter Earth from the Moon.
12. View of Earth from the Moon.
13. Views of Earth from space. We see Earth as it would appear from space at different times of the day.
14. Planet Earth as seen from space. In this view, it’s easy to pick out places where the Earth’s crust is pulling apart, forming new ocean basins.
15. Here is the back side of Earth’s moon, the side we never see from Earth. • Mean radius of orbit: 385,000 km • Period of revolution: 27.3 d • Surface gravity: 0.165 x Earth’s.
16. Earth viewed from space, with Antarctica at the bottom.
17. Mare Orientale on the moon was formed by a meteorite impact. The impact liquified the rocks on the Moon. Waves went rolling out and then hardened to create the two rings on the outside.
18. Here is the Moon, with Mare Orientale in the center. Bright spots are recent impact craters. The brightness is from rock that melted on impact and hardened into glass. These spots will darken with age.
This color image of Earth's moon was taken by the Galileo spacecraft on its first gravity-assist pass by the Earth on December 8, 1990.
19. Astronaut’s boot print on the Moon. Because there is no atmosphere and little erosion, this boot print will probably remain visible for millions of years.
20. Here is a rare shot of Earth and Moon in one picture, taken at the beginning of the Voyager 1 mission to the outer solar system.
21. Hans Lippershey, in the Netherlands, invented the telescope in 1608 for the military. Galileo later perfected the device for astronomical use.
22. This drawing shows the shuttle approaching NASA’s Hubble Space Telescope so that the astronauts can perform periodic maintenance.
23. The Earth Observing System (EOS) will carry 10 instruments to observe the surface and atmosphere of the Earth for more than a decade.
24. Here is a picture of the Sierra Nevada mountain range (California and Nevada) from 225 miles above.
25. Here is an image of a great cyclonic storm on the Earth.
26. Los Angeles from space.
27. This Apollo 16 picture shows us southern California and Baja California.
28. A picture of the East Coast of the United States, from space.
29. Crescent Earth rising over the Moon.
30. Northern Gulf of California.
31. This picture shows the delta of the Nile River.
32. The Mediterranean Sea, as seen from orbit.
33. This picture shows the Himalayas, the tallest mountain range on Earth.
34. This is an image of southern California. The lake on the upper left is the Salton Sea. The red area is the Imperial Valley, rich in farmland. To the right is the border of the United States and Mexico.
35. Gulf of Mexico.
36. Weather patterns on the Earth.
37. Mountains jut above the city of Kweilin in China, like pieces on a giant chess board.
38. Jagged mountains outside Kweilin, China are reflected in the rice paddies. The paddies are planted with new seedlings.
39. Snow-capped peaks in the French Alps, like this one at Val d’Isère, rise above the timberline.
40. “Fish Tail Mountain” above Pokara, Nepal lies in the Himalayas. The tallest mountains on Earth are puny compared to those on Mars.
41. Mountains loom through the fog on the Li River near Kweilin, China. This photo looks like a painting, but it is a real photograph.
42. The Sun is starting to set over Baobob trees in Senegal, Africa. Actually, it is the Earth rotating away from the Sun that makes the Sun appear to set.
43. At dusk, these mountain ranges in Colorado seem to fade into the distance. On Earth, distant objects appear to fade because you are looking through more air to see them.
44. At sunset in the Rocky Mountains, cars turn on their headlights. Night falls because the Earth is rotating away from the Sun.
45. Crops can grow on barren land where irrigation can bring water. Here is a view of a high mountain desert in Ladakh, northern India.
46. This barren landscape may look like some other planet, but it is Earth, and humans actually live here. See the previous picture, of Ladakh.
47. Cumulus clouds billow up behind a temple in Katmandu, Nepal.
48. The atmosphere of Earth is filled with constantly changing cloud patterns. These clouds are seen from an airplane flying at 20,000 feet.
49. A man huddles against the rain under a bamboo umbrella. Rice paddies are visible below the cliff.
50. Life on Earth thrives around water. Hallam Lake is a quiet place for plants and animals near the center of town in Aspen, Colorado.
51. Goldfish swim in this human-made grotto in the Bagatelle in Paris, France.
52. The Sun melts the ice around this waterfall in Idaho Springs, Colorado. The Earth is the only planet where water occurs as a liquid, a solid, and a gas.
53. Water buffalo escape the heat with a nice cool mud bath near Changmai, Thailand.
54. Johannes Kepler (1571–1630), a German astronomer (left), discovered that the Earth and planets travel in elliptical orbits around the Sun.
55. Aristotle, Ptolemy, and Copernicus on the title page of “Systemate Mundi” (“Dialogue of the Systems of the World”) by Galileo Galilei, 1632.
56. The Sahara Desert, as seen from orbit. Sand dunes can be seen in the top of the picture.
57. Youthful mountains on Earth, in a photo taken from orbit.
58. The Apollo 10 Command Module is seen above the Moon. The Lunar Module separated and descended towards the Moon’s surface to practice for Apollo 11.
59. Map of the lunar landing site for the Apollo 16 mission.
60. Orange soil near Shorty Crater on the Moon, discovered during the Apollo 17 mission.
61. Copernicus Crater on the Moon. Here we see the wall of the crater. If we could look over the side, we would see a steep drop-off into the crater.
62. Here we see the Marius Hills on the Moon, volcanic domes which stick up above the surface. A crater can be seen in the background. Wrinkle ridges from lava flows can be seen in the foreground.
63. Here we see Taurus-Littrow Valley on the Moon. Note the tiny Apollo 17 lander near the exact center, above the small hill.
64. Goclenius Crater on the Moon. Notice the cooling cracks where the surface has split and dropped down.
65. King Crater on the Moon.
66. This meteor crater in Arizona is about one mile across. It is one of the freshest big impact craters on Earth. The Meteor was a chunk of iron about a 10th the size of the crater.
67. The surface of the Moon.
68. The Moon’s Hadley Rille as seen from orbit. This was the touchdown area for Apollo 15.
MARS
1. Mars has its own Grand Canyon, Valles Marinaris, which extends across the middle of this image. The three faint spots to the far left are craters called North Spot, Middle Spot, and South Spot.
This photo was created from of 104 images taken by NASA’s Viking Orbiter 1 spacecraft during its mission to Mars which began in 1976.
Valles Marineris is approximately 5,000 km (3,000mi) long—about the width of the United states from the Atlantic Ocean to the Pacific Ocean. Some of the canyons are up to 250 km (155 mi) wide.
Meteorite impact cratering varies from the heavily scarred southern hemisphere to the sparsely cratered regions in the northern latitudes. The three large dark circles seen at the left are enormous volcanoes. They rise over 26 km (16 mi)—far higher than any on Earth. It is thought that lava from these volcanoes flooded much of the Martian northern hemisphere, erasing many impact craters.
This mosaic of Mars is similar to the view you would see from a space- craft. The center of the scene shows the entire Valles Marineris canyon system, over 3000 km (1860 mi) long and up to 8 km (5 mi) deep. It extends from Noctis Labyrinthus, the arcuate system of graben on the west side, to the chaotic terrain on the east side. Many ancient river channels begin from the chaotic terrain and north-central canyons and run north. Three Tharsis volcanoes (dark red spots), each about 25 km (16 mi) high, are visible to the west.
2. This view of Mars is highly cratered. Half of Mars is heavily cratered and half has been resurfaced by modern lava flows.
This mosaic of Mars is composed of about 100 Viking Orbiter images. The images
were acquired in 1980 during mid-northern summer on Mars. Crater Schiaparelli,
left of center, is 450 km (279 mi) in diameter. The dark streaks with bright
margins emanating from craters in the Oxie Palus region, in the upper left,
are caused by erosion and deposition by the wind. Bright white areas to the
south, including the Hellas impact basin at extreme lower right, are covered
by carbon dioxide frost.
3. This image shows part of the less interesting surface of Mars, with few signs of volcanos or impact craters.
This view of Mars is similar to what you would see from a space-craft. Thin
white clouds are dispersed over the northern hemisphere. Other features
include the large dark area left of center named Cerberus. The Elysium
volcano, a yellow area north of Cerberus, has several channels radiating from
its flanks. To the right of center is the crater Tettit, with its peculiar
dark "tail." The arcuate markings, upper right, are in the Amazonis plains and
may be sand drifts. The 3 bright spots, upper left, are volcanoes partially
veiled by thin clouds.
4. This photo shows the southern icecap. It was taken in the middle of the Martian summer, so the carbon dioxide ice has evaporated away. What is left is actual snow on the surface of Mars.
The south polar cap shrinks in size during the Martian summer and increases
during the winter. The temperature at the pole is at least as cold as carbon
dioxide ice, 130 K (-225 F), throughout the Martian year. The cap is
approximately 500 km (311 mi) in diameter.
5. A view of Mars, from the Viking mission. A large impact crater can be seen on the right.
6. This Viking close-up of the northern polar region of Mars shows a mixture of dust and ice. Cycles of freezing combined with periodic dust storms formed these striped layers.
7. The snow at the north pole of Mars is frozen water and carbon dioxide. Each ice cap on Mars has a spiral appearance. The cause of this spiral formation is unknown.
8. The south polar ice cap on Mars is much smaller than the northern icecap. It too has snow made of frozen water and carbon dioxide.
9. In this artist’s view, the Mars Observer spacecraft scans the surface of the red planet. Mars Observer is the first mission to use the new, low-cost Observer class spacecraft.
10. Olympus Mons, the highest volcano on Mars, has a caldera in the center. (Calderas are holes created when a volcano sinks in after cooling.) The white ring is cliffs.
Olympus Mons is the largest volcano in the solar system. This shield volcano,
similar to volcanoes in Hawaii, measures 700 km (434 mi) in diameter by 25 km
(16 mi) high. It is 100 times larger than Mauna Loa on Earth. Located on the
Tharsis Plateau near the equator, Olympus Mons is bordered by an escarpment.
The caldera in the center is 80 km (50 mi) wide and contains multiple
circular, overlapping collapse craters created by different volcanic events.
The radial features on the slopes of the volcano were formed by overflowing
lava and debris.
11. Olympus Mons, a volcano on Mars, may be the most spectacular volcano in the solar system. It’s about three times the height of Mt. Everest, 27 km high.
12. Aerial view of Olympus Mons in false color.
13. A 3-D model of the volcano Arsia Mons on Mars, located in the Tharsis Montes region.
14. Close-up of escarpment at base of Olympus Mons. The escarpment is about a mile high. This shows only a small portion of the 600 km diameter base.
15. Here is a Viking photo of Mars’s Mangala Vallis region, showing a network of channels. This supports the theory that liquid water existed on Mars at one time.
16. This is a synthesized view of canyons on Mars. Notice the signs of a huge landslide along the left edge.
This image is an oblique view of Central Candor Chasma in Valles Marineris on
Mars. This spectacular view was reconstructed from high resolution black and
white images acquired on orbits 912, 914, 913, 915, and 917 of Viking 1,
combined with high resolution color images acquired on orbit 279 from Viking
2. The image reveals a complex geomorphology, shaped by tectonics, mass
wasting, and wind, and perhaps by water and volcanism. This particular view of
Candor Chasma is from the west.
17. Cratered uplands of Mars. The lighting makes these craters seem like bumps, but they’re actually holes.
18. Mist shrouded canyons of Coprates Chasma. The sun heats the surface frost from the previous night, creating water vapor.
The sun’s rays heat surface frost from the previous night producing water vapor, which recondenses into a mist composed of ice crystals in the cold atmosphere. This “radiation mist” provides proof that water ice can exist in the Martian soil during winter.
19. Voyager photo of channels in Lunae Planum shows further evidence of liquid water erosion. The largest crater shown measures about 75 km across.
These channels are similar to fluvial channels seen on Earth. Liquid water does not now exist in Mars. The largest crater shown measures about 75 km across. That is close to 50 miles.
20. Viking close-up of Ius Chasma, part of the huge Valles Marineris canyon on Mars. Note the evidence of spectacular landslides.
Note the evidence of spectacular landslides which have eroded the valley bank. These huge landslides could still be occuring today.
21. Viking photo of the mouth of Ares Valles shows cratered islands left by what appears to be a catastrophic flood caused a natural dam breaking.
Water appears to have come from the bottom left direction.
22. The crater Arandas on Mars, showing a central peak characteristic of meteorite impact craters. The crater is 28 km in diameter.
Note the ejecta blanket at left formed from the material displaced from the crater at impact. The blanket could have been mud. Water can only exist on Mars in a frozen state but heat from the impact may have melted the ice, producing a massive flow of mud.
23. Looking down on the Tharsis Montes region of Mars. The dark spot is one of the three Tharsis volcanos.
24. A sudden melting of ground ice could have caused the collapse of this depression on Mars, forming the outlet channels at the left.
The event may have been similar to a huge dam bursting on Earth. The biggest width of the depression is 40km.
25. Close-up of Ganges Chasma, part of the Valles Marineris canyon system on Mars. The cliff is 8 km (5 mi) high and about 56 km (35 mi) across.
Note the debris on the canyon floor that must have been the result of some spectacular collapses along the canyon wall. These collapses, caused by gravity, may still be occurring today.
26. This Viking photo shows a close-up view of the 90 km caldera of Olympus Mons. This inactive volcano is 27 km (16 mi) high.
27. Surface of Mars. The flat section is the floor of the crater, and you can see towards the bottom of the picture where fluid flowed out of the crater.
28. Lava flows on Mars. Planetary scientists do not know when Martian volcanoes became inactive.
29. Lava flows on Mars.
30. A portion of Valles Marineris on Mars.
31. The surface of Mars, as seen from the Viking lander.
32. A picture of the Viking 2 landing site. The rounded rock in the center foreground is about 20 cm wide. Near it are trenches that were dug by the lander. The object to the right is a camera piece that was ejected.
The angular rock to the right and further back than the rounded rock is about 1.5 meters across. The dark facet on the upper right edge of the angular rock has a color similar to basalts on Earth. There are two trenches that were dug in the regolith to the right of the rounded rock, as well as one behind and slightly to the left. The gently sloping troughs between the artificial trenches and the angular rock which cut from the middle left to the lower right corner of the picture are natural surface features.
33. View of Utopia Planitia on Mars. Iron oxides (rust) probably give the soil its reddish color. The antenna in the foreground, pointing towards Earth, sent this picture.
34. A rocky field at the Viking 1 landing site. Patches of drift material, and possibly bedrock, are visible farther from the lander.
There were two cameras on each of the two Viking Landers, so stereo imagery could be acquired for a portion of each of the sites. Thus, three dimensional products, such as topographic maps, could be constructed. This scene shows a rocky field. In the foreground activity from the sampler arm is evident in the trenched and disturbed surface.
35. Viking close-up of the Argyre Basin, a huge meteorite impact crater with an inner diameter of 900 km. A small portion of the basin is at the top left.
A portion of the basin is seen top-left and the ejecta blanket (material displaced on impact of the meteorite) runs diagonally from lower left to upper right. The ejecta blanket has an outer diameter of 1400 km. The Argyre basin is located in the ancient, heavily cratered southern hemisphere of Mars and was formed shortly after the formation of the planet 4.5 billion years ago. In general, heavily cratered regions signify ancient terrain because meteorites and space debris were much more abundant in the very early solar system. Note the smaller craters from later impacts that dot the ejecta blanket.
36. View of Utopia Planitia, the Viking 2 landing site. The grooves in the ground near the lower right were made when the lander scooped up soil samples.
One of the principal purposes of the mission was to look for life. None was found.
37. Viking 2 observed the surface at Utopia Planitia for several Martian years. This winter morning shot shows frost made of carbon dioxide and water.
The frost was produced by low nighttime temperatures of -113°C (-171°F). The frost is mostly water and ice.
38. Chryse Planitia landing site of Viking 1. The Viking 1 lander just missed hitting the large boulder to the left. The boulder was nicknamed “Big Joe.”
Chryse Planitia landing site of Viking 1 shows a few large boulders surrounded by small rubble and fine sand. The large boulder located at the left was nicknamed “Big Joe”, and measures about 1 m high. It may have been tossed to the site by a meteorite impact (note the circular arcs of smaller rocks around Big Joe). The Viking 1 lander just missed hitting this boulder.
39. The Mars Rover Sample Return mission will send a lander to Mars to collect soil samples to send back to Earth.
40. Clasp of Phobos (“Terror” in Greek), one of the two Martian moons. The large crater Stickney is about 10 km across. This massive impact cracked Phobos, forming the diagonal line near the bottom.
Like most other moons in the solar system, Phobos is locked in synchronous rotation with Mars which means that it always keeps the same face oriented towards Mars. Because Phobos’ orbital period is much less than Mars’ period of rotation, Phobos would appear to an observer on Mars to zip eastward at the very fast rate of 57 degrees per hour. Phobos’ equatorial orbit is so small that observers on the Martian polar caps would not be able to see it. Because Phobos lies inside the synchronous orbit distance (the distance where the orbital period of the satellite matches the rotational period of the planet), it is spiraling in towards Mars. Phobos will impact on Mars in the next 100 million years. Phobos and Deimos (the other Martian moon) reflect only about 5 % of the Sun’s light. Their surfaces are estimated to be 2.5-3 billion years old. Phobos and Deimos differ dramatically in chemical composition from Mars. Their similarities to the asteroids have led to speculation that Phobos and deimos may be captured asteroids. PHOBOS • Mean radius of orbit: 9,380 km • Period of revolution: 0.319 d • Maintains same face toward planet? Yes • Dimensions: 27x21x19 km • Mass: 9.6 E15 • Density: 2g/cc? • Surface gravity: 0.0017 times Earth’s • First observed: 1877
41. An airbrush drawing of Phobos, one of two small moons that orbits Mars.
42. Viking orbiter photo of the Martian moon Phobos. This image shows a close-up of the grooves thought to be associated with the impact of Stickney.
43. Deimos, a very small moon of Mars. The surface is covered with dust, which hides the surface features. The light section at the bottom is a ridge.
This computer mosaic of Deimos was made with images acquired from Viking
Orbiter during one of its close approaches to the moon. The 13-km (8-mi)
diameter Deimos circles Mars every 30 hours. Scientists speculate that Deimos
and its companion moon Phobos were once passing asteroids that were pulled in
by the gravity of Mars.
Viking orbiter images of Deimos (“Panic” in Greek), one of Mars’s two moons. Deimos is locked in synchronous rotation with Mars which means that it always keeps the same face oriented towards Mars. Because Deimos’s orbital period is a little longer than Mar’s period of rotation, Deimos would appear to an observer on Mars to move westward at the slow rate of 2.8 degrees per hour. Because Deimos is just outside the synchronous orbit distance (the distance where the orbital period of the satellite matches the rotational period of the planet), it is spiraling slowly outward, away from Mars. Deimos and Phobos (the other Martian moon) reflect only about 5 % of the Sun’s light. Their surfaces are estimated to be 2.5-3 billion years old. Phobos and Deimos differ dramatically in chemical composition from Mars. Their similarities to asteroids have led to speculation that Phobos and Deimos may be captured asteroids. DEIMOS • Mean radius of orbit: 23,500 km • Period of revolution: 1.26 d • Maintains same face toward planet? Yes • Dimensions: 15x12x11 km • Mass: 2.0 E15 kg • Density: 2g/cc? • Surface gravity: 0.00050 times Earth’s • First observed: 1877
44. Viking 2 took this close-up of Mars’s moon Deimos from a distance of only 60 km. The lack of heavy cratering suggests that Deimos is the younger moon.
JUPITER
1. A processed image of Jupiter and Io. Io is actually quite small compared to Jupiter. Note that the Great Red Spot on Jupiter is four times the size of Earth, while Io is about the size of Earth’s Moon.
2. Jupiter and its ring. (Artist’s drawing of the ring.)
Voyagers 1 and 2 sent back spectacular images of the Jovian system and made startling discoveries. Giant volcanoes spew molten sulfur hundreds of kilometers above the surface of Io, one of Jupiter’s four largest moons. The other large satellites, Europa, Ganymede and Callisto, have diverse surfaces. Three tiny moons were found near a thin ring of dust particles encircling the planet, and cloud-top lightning bolts and polar auroras were observed lighting up Jupiter’s night skies.
3. Jupiter, the largest planet in the solar system, is a giant gas ball. Jupiter’s banding and famous Great Red Spot are clearly shown in this image.
Jupiter is composed primarily of hydrogen
4. This mosaic of photos shows the ring around Jupiter.
5. Two of the four Galilean satellites appear here against the background of Jupiter. They are Io (left) and Europa.
6. Here is Jupiter, viewed from a spacecraft. Note the light and dark zones. The light clouds and dark clouds on Jupiter actually move in opposite directions.
7. This true-color picture of Jupiter was taken to help us understand the cloud and wind systems on Jupiter.
8. False color was used here to enhance atmospheric features surrounding Jupiter’s Great Red Spot. Voyager 2 took this photo in 1979.
9. This brown oval on Jupiter is about the same size as the Earth! We are seeing through the upper clouds into a darker region deeper in the atmosphere.
10. The Great Red Spot on Jupiter, here seen as observed by Voyager 2, is an elevated high pressure region, rotating counterclockwise around the planet.
11. An aurora effect that was detected by Voyager, as it looked back at the dark side of the planet Jupiter. The little bright spots are lightning strikes which lit up the clouds during the three minute exposure.
The aurora effect is caused by electrons streaming in from Io’s torus; the electrons then interact with the Jovian ionosphere.
12. Voyager image of the Great Red Spot on Jupiter.
13. Jupiter’s ring is very faint. Scientists believe that the particles in the ring come from Io’s volcanoes.
14. Io is seen against the background of its parent planet, Jupiter. While Io looks small here, it is actually about the size of Earth’s own Moon.
15. Jupiter, Io, and Europa.
16. Here is a close-up of Jupiter’s Great Red Spot, in a false-color image.
17. Close-up of Jupiter’s Great Red Spot.
18. Computer mosaic of Jupiter’s atmosphere, as seen from its north pole.
19. This Voyager 1 picture of Jupiter’s Great Red Spot was taken in 1979 from a distance of 5.7 million miles.
20. This large brown oval may be an opening in the upper cloud deck. It provides information about deeper, warmer cloud levels in Jupiter’s atmosphere.
21. This view of the Great Red Spot on Jupiter is enhanced with computer generated color to show small details of color and shading.
22. This Voyager 2 picture shows the Great Red Spot and the south equatorial belt, extending into the equatorial region.
23. Voyager close-up of Jupiter’s moon Europa. These dark lines may be fractures that have been filled in with silicate-bearing ice from below.
24. A close-up view of Jupiter’s moon, Europa (enhanced).
25. Europa has almost no craters. It is mostly made up of rock. Its light, highly reflective surface is water ice that is not more than 100 km (60 mi) thick.
26. Europa has an ice crust about 100 km (62 mi) thick. The absence of craters suggests that the ice crust is young. Europa is the same size as our Moon.
Europa is mostly made up of rock. Europa’s light, highly reflective surface is water ice not more than 100 km (60 mi) thick.
27. Voyager image of Jupiter’s moon Europa.
28. This is Io, one of four satellites of Jupiter discovered by Galileo in 1610. Sulfur is thought to produce Io’s unique color.
28. Voyager image of volcanic eruptions on Jupiter’s moon Io. The plumes of the eruptions just catch the light from the Sun.
30. Voyager close-up of Loki Patera on Io. False color enhances the caldera, the dark “horse shoe” in the lower left. The caldera’s temperature was 63°F.
31. This false-color picture of an eruption of Loki on Io shows a yellow part of the plume rising about 100 km and a blue part rising about 200 km.
32. This Voyager 1 image is of Jupiter’s moon Io. Note the abundance of volcanic calderas, the dark oval blotches.
33. This close-up of Io shows a caldera (the black oval) and the rivers of out-flowing lava. The lack of craters indicates that Io’s surface is very active.
34. This Voyager 1 picture shows a huge volcanic explosion on Io. The greenish white color is the true color. The faint plume is computer enhanced.
35. Voyager 2 picture of Jupiter’s moon Ganymede shows a heavily cratered dark region in the upper right called Galileo Regio, almost 2,000 miles across.
36. Bizarre grooved terrain is shown on Ganymede. The grooves are made of water ice and may be from the crust cracking after a big impact.
37. This shows the dark polygonal terrain and the surrounding bright bands unique to Ganymede. Galileo Regio, the dark region at the upper right, is the trace of a huge impact in the distant past.
38. Ganymede’s grooved terrain was likely formed over a period of hundreds of millions of years.
39. This Voyager 1 image of Ganymede was taken in 1979. It shows that the surface is separated into dark regions surrounded by lighter ones.
40. Many craters are visible in this picture of Ganymede.
41. This picture of Ganymede shows a bright halo impact crater with fresh material thrown out of its crater.
42. A Voyager 2 image of Jupiter’s moon Callisto. Incoming meteorites crashing into the dirty water-ice surface produced the bright spots seen here.
43. The large number of impact craters on Callisto tells us that the surface is about four billion years old, possibly the oldest in the solar system.
This close–up of Jupiter’s moon Callisto was made from nine Voyager 2 pictures taken in 1979. The craters are almost the same size, with diameters up to 100 km. (62 miles)
44. The Valhalla basin on Callisto (the bright region on the left side) was probably caused by a huge meteorite impact at least 4.3 billion years ago.
45. Amalthea, one of Jupiter’s smaller moons, is named after a mysterious goddess. This moon is twice as wide as it is thick.
46. The four Galilean satellites of Jupiter are Io, Europa, Ganymede, and Callisto.
47. This artist’s drawing shows the Galileo probe as it approaches Jupiter’s stormy atmosphere to take samples of cloud layers.
Future Missions and uncrewed space explorations are being planned from now until the early part of the next century. The probe shown here will transmit the data to the orbiter which will then send the information back to Earth.
48. The Galileo spacecraft used the gravity of Venus and Earth to travel on to Jupiter, arriving there in 1995.
SATURN
1. Voyager 2 at Saturn.
2. This picture of Saturn was taken from Earth, 860 million miles away. The dark gap near the outer edge had never been photographed before from Earth.
This picture of Saturn was taken from Earth 1.39 billion kilometers away, or 860 million miles.
3. This picture uses two colors to show details of a storm which erupted on Saturn in late 1990.
4. A photo of Saturn taken by Voyager 2. Two bright cloud patterns can be seen in the mid-northern hemisphere. A moon, Rhea or Dione, appears in the corner.
5. Mimas’s huge crater.
6. Voyager 2 at Saturn.
7. Voyager 2 just before crossing Saturn’s rings.
8. View of Saturn with its rings.
9. Saturn with its rings.
10. Crescent Saturn. Notice that Saturn casts a shadow on its rings and the rings to the right cast a thin shadow on Saturn.
11. Global mosaic of Saturn.
12. Saturn’s rings are seen from below by Voyager 1 as the spacecraft passes the planet’s dark side.
13. Saturn’s rings are made up of a huge number of individual particles. These particles range in size from microscopic to chunks the size of a truck.
14. Flyover of Cassini’s division in Saturn’s rings.
15. Saturn’s rings are made up of 10,000 or more separate ringlets. The darks spots spin with the rings and each ring spins at a different speed.
16. Voyager 2 just after ring crossing.
17. Voyager image of Saturn’s rings. Color is enhanced to show the immense complexity of the Saturn ring system.
18. The F-ring of Saturn is made up of three rings. The two rings in this picture are braided and seem to defy the normal laws of particles in orbit.
19. Profile of the A ring on Saturn. The complexity and variety of the ring system of Saturn is shown in this photo.
20. The Voyager missions found “shepherd” satellites, so named because they seem to influence the shape and distribution of the ring system of Saturn.
21. Edge of Saturn’s rings.
22. The “F” ring of Saturn.
23. Dione’s trailing hemisphere is protected from impacts, yet it has ancient crustal breaks from icy fluids which migrated to the surface.
24. Dione’s leading hemisphere is heavily cratered. The history of these impact craters goes back billions of years.
25. This Voyager 1 image of Saturn’s moon Dione shows a close-up of the moon’s bright hemisphere. Heavy cratering shows that the surface of Dione is quite old.
26. This image of Enceladus, one of Saturn’s moons, was made by combining several pictures from Voyager 2. The pictures were taken from a distance of 119,000 km (74,000 mi).
27. Saturn’s moon Enceladus has smooth plains and long winding ridges. Some astronomers think that Enceladus might have active ice volcanoes.
28. A large part of the Enceladus surface has no craters. Enceladus may be the source of the water-ice particles that make up Saturn’s E-ring.
Saturn’s moon, Enceladus, was photographed by Voyager 2. A large part of the surface is craterless, and so should be very young in geologic terms. The surface is highly reflective.
29. This picture of Saturn’s moon, Titan, was taken by Voyager 2 as it looked back at the night side of the planet. Sunlight is reflected off an aerosol layer of tiny particles in Titan’s atmosphere.
30. Saturn’s moon Titan. The atmosphere is so thick with clouds that no features can be seen.
31. Saturn’s mysterious moon, Titan. Slightly larger than the planet Mercury, Titan is the second largest moon in the Solar System.
TITAN • Mean radius of orbit: 1.22 E6 km • Period of revolution: 16.0 d • Maintains same face toward planet• Radius: 2,580 km • Mass: 1.36 E23 kg • Density: 1.9 g/cc • Surface gravity: 0.14 times Earth’s • First observed: 1655
32. This is one of Saturn’s moons, Titan, photographed through a thick haze.
33. This cloud-covered photo of Titan shows a difference in the brightness and color from the northern hemisphere to the southern hemisphere.
34. This montage of Voyager images shows the relative sizes of 8 of Saturn’s moons. From left to right and top to bottom they are Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus, Hyperion, and Phoebe.
35. Hyperion, one of Saturn’s moons, is irregular in shape, like a flattened hamburger. Hyperion is only 360 kilometers across (about 235 miles).
36. Voyager took this photo of Saturn’s moon Hyperion in 1981. Normally, objects this size have a nice rounded shape. Hyperion’s dimensions are 410 x 260 x 220 km.
37. Tethys is a moon of Saturn. This Voyager 2 image was taken in August of 1981.
38. This picture of Saturn’s moon Tethys shows a huge canyon system.
39. Tethys has a heavily cratered surface. The faint channel running from the large crater down to the left is Ithica Chasma, 62 miles wide.
Ithica Chasma is a gigantic valley running 3/4 of the way around the satellite (over 1243 mi or 2,000 km). The valley is 62 miles (100 km) wide and several miles deep
40. This is Rhea, Saturn’s fifth moon. From its density, scientists think that Rhea consists mostly of water ice, with a small amount of rocky material.
41. Rhea is the second largest moon of Saturn. The heavy impact cratering seen here makes Rhea’s surface one of the oldest in the Saturnian system.
42. This Voyager 2 image of Iapetus shows two distinct materials on this icy world. Half the surface is dark, and may be made from materials that fell from Phoebe, another moon of Saturn.
43. Saturn’s moon Iapetus is one of the strangest objects in the solar system. It has a dark leading hemisphere and a bright trailing hemisphere.
44. Two views of Saturn’s moon Iapetus. Note the striking difference in the appearance of the moon from two different angles.
45. Voyager 1 took this photo of Saturn’s moon Mimas from a distance of 500,000 km (310,000 mi). Voyager passed through the Saturnian system in November of 1980.
46. This heavily cratered image of Saturn’s moon Mimas tells us much of Saturn’s violent past.
47. The impact which produced the large crater seen here on Mimas may have almost shattered the moon.
48. In this drawing, the Cassini spacecraft arrives at Titan, Saturn’s largest moon. Mariner Mark II will probe to sample the atmosphere.
49. Voyager 1 and Titan flyby.
50. Eight of Saturn’s moons are shown from left to right and top to bottom. They are Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus, Hyperion, and Phoebe.
51. Seven of Saturn’s 24 known moons are shown in this Voyager montage, which is NOT to scale. The sixth largest moon, Enceladus, is featured in the lower left.
52. Saturn’s smaller satellites.
53. This Voyager 1 image shows the red oval cloud feature found in Saturn’s southern hemisphere. It was taken at a distance of 8.5 million kilometers (5.3 million miles).
54. A Voyager 2 picture showing the Saturnian system. Dione is up front, then Tethys, Mimas is to the right; Enceladus, and then Rhea are to the left; Titan is at the upper right.
This montage of the Saturnian system was prepared from an assemblage of images taken by Voyager 1 during its Saturn encounter in 1980. Gaps in the rings are clearly visible, as are the shadows of the rings on the planet and of the planet ring.
55. This picture shows Saturn and two of its moons, Tethys (above) and Dione. It was photographed by Voyager 1 in 1980, at a distance of 13 million km.
Cassini Division separates the A- and B-rings. The view through the much narrower Encke Division, near the outer edge of the A-ring is less clear. Beyond the Encke Division is the faintest of Saturn’s three bright rings, the C-ring or crepe ring, barely visible against the planet.
56. False color view of Saturn’s atmosphere. Infrared observations show the bands of color, revealing different altitudes in the atmosphere.
57. Titan is Saturn’s largest moon. In this false-color photo, a layer of light haze at an altitude of 300 km is clearly separated from the main haze layer. The main haze is the golden layer.
URANUS
1. Uranus and its ring are pictured here in this collage as they might be seen from the Uranian moon Miranda.
2. These true- and false-color images of Uranus were taken in early 1986, by a narrow-angle camera on board Voyager 2.
3. These time-lapse images, taken in 1986, show the movement of clouds on Uranus. The photos were taken with orange filters over a 4.6 hour interval.
4. The known rings of Uranus are made of eleven thin dark rings ranging in distance from 37,000 to 51,160 km (once around the earth is 40,000 km).
5. A computer enhanced image of the rings of Uranus shown in false color. Scientists use enhanced images to study the nature of the rings.
This false-color view of the rings of Uranus was made from images taken by Voyager 2 on Jan. 21, 1986, from a distance of 4.17 million kilometers (2.59 million miles). All nine known rings are visible here; the somewhat fainter, pastel lines seen between them are contributed by the computer enhancement. Six 15-second narrow-angle images were used to extract color information from the extremely dark and faint rings. Two images each in the green, clear and violet filters were added together and averaged to find the proper color differences between the rings. The final image was made from these three color averages and represents an enhanced, false-color view. The image shows that the brightest, or epsilon, ring at top is neutral in color, with the fainter eight other rings showing color differences between them. Moving down, toward Uranus, we see the delta, gamma and eta rings in shades of blue and green; the beta and alpha rings in somewhat lighter tones; and then a final set of three, known simply as the 4, 5 and 6 rings, in faint off-white tones. Scientists will use this color information to try to understand the nature and origin of the ring material. The resolution of this image is approximately 4O km (25 mi).
6. The rings of Uranus are similar to those of Jupiter and Saturn, however their dark color suggests the lack of frozen water, methane or ammonia.
7. Image of Uranus from Voyager 2’s closest approach.
8. Uranus and Miranda, one of the planet’s many moons.
9. Voyager 2 at Uranus
10. Voyager 2 images of Miranda were assembled to produce this picture. Note the large oval of unique terrain in the center.
11. Miranda, the mysterious moon of Uranus, has unusual ridges on its surface.
12. Voyager 2 close-up of the point of the chevron on Uranus’ moon, Miranda.
13. This image of Miranda, a moon of Uranus, shows a large fault line (center right). Its walls are 3 miles higher than those of the Grand Canyon.
This image of Miranda, one of the Uranian moons, was taken in 1986. The picture shows a varied surface with lots of ridges and valleys. The objects appearing in this picture are close to 2,160 feet across. There are also many fault lines seen in this image. The largest fault is toward the center right. The grooves seen here are made by the fault blocks as they rub against each other, leaving behind what are known as slickensides. The fault is about 5 km or 3 miles higher than the walls of the Grand Canyon here on Earth.
14. Many pictures were used to create this image of the surface of Uranus’ moon Ariel. The faults suggest past tectonic activity.
15. This is a Voyager 2 image of Uranus’ moon, Ariel, taken in 1986. Ariel has a diameter of only about 1,2OO km (75O mi).
16. The complex terrain of Ariel is viewed in this image. Ariel has clearly experienced a great deal of geological activity in the past.
The complex terrain of Ariel is viewed in this image, the best Voyager 2 color picture of the Uranian moon. The individual photos used to construct this composite were taken Jan. 24, 1986, from a distance of 170,000 kilometers (105,000 miles). Voyager captured this view of Ariel’s southern hemisphere through the green, blue and violet filters of the narrow-angle camera; the resolution is about 3 km (2 mi). Most of the visible surface consists of relatively intensely cratered terrain transected by fault scarps and fault-bounded valleys (graben). Some of the largest valleys, which can be seen near the terminator (at right), are partly filled with younger deposits that are less heavily cratered. Bright spots near the limb and toward the left are chiefly the rims of small craters. Most of the brightly rimmed craters are too small to be resolved here, although one about 3O km (2O mi) in diameter can be easily distinguished near the center. These bright-rim craters, though the youngest features on Ariel, probably have formed over a long span of geological time. Although Ariel has a diameter of only about 1,200 km (750 mi), it has clearly experienced a great deal of geological activity in the past.
17. Uranus’ outermost moon, Oberon, is heavily cratered, indicating that its surface dates back to the early period of solar system history.
This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus’ outermost moon. The picture was taken shortly after 3:3O a.m. PST on Jan. 24, 1986, from a distance of 660,000 kilometers (410,000 miles). The color was reconstructed from images taken through the narrow-angle camera’s violet, clear and green filters. The picture shows features as small as 12 km (7 mi) on the moon’s surface. Clearly visible are several large impact craters in Oberon’s icy surface surrounded by bright rays similar to those seen on Jupiter’s moon Callisto. Quite prominent near the center of Oberon’s disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb.
18. Quite prominent near the center of Oberon’s disk is a large crater with a bright central peak and a floor partially covered with very dark material.
19. Titania is Uranus’ largest moon. One explanation for the many cracks and valleys is that as the moon cooled down, it contracted and fractured.
20. Titania is one of the large moons of Uranus. The natural gray color is typical of all the Uranian satellites.
Titania is one of the large moons of Uranus. The Spacecraft was about 300,000 miles away when it took this picture. The picture shows details of 6 miles in size. The diameter of Titania is about 1000 miles across. We can see clues of the geologic activity that took place in Titania’s history. To the middle right there is a large trench that tells us of tectonic movements from the past. To the upper right there is an area of high activity from heavy impacts. The natural gray color is common among all the Uranian satellites.
21. Umbriel the third satellite of Uranus is extremely dark. The cause for the darkness still remains a mystery.
The other satellites found inside and outside Umbriel’s orbits are much brighter. Umbriel has a dark surface with a few bright icy white rings that have been left behind.
NEPTUNE
1. Neptune’s atmosphere is shown here. The large dark oval near the left edge is a storm system which circles the planet every 18.3 hours.
During August 16 and 17, 1989, the Voyager 2 narrow-angle camera was used to photograph Neptune almost continuously, recording approximately two and one-half rotations of the planet. These images represent the most complete set of full disk Neptune images that the spacecraft will acquire. This picture from the sequence shows two of the four cloud features which have been tracked by the Voyager cameras during this time period. The large dark oval near the western limb (the left edge) is at a latitude of 22 degrees south and circuits Neptune every 18.3 hours. The bright clouds immediately to the south and east of this oval are seen to substantially change their appearances in periods as short as four hours. The second dark spot, at 54 degrees south latitude near the terminator (lower right edge), circuits Neptune every 16.1 hours. This image has been processed to enhance the visibility of small features, at some sacrifice of color fidelity.
2. This picture of Neptune shows Neptune’s Great Dark Spot and weather patterns that travel around Neptune at different speeds.
3. Strong eastward winds up to 400 mph cause the second dark spot in the lower part of the picture to overtake and pass the larger one every five days.
This image of clouds in Neptune’s atmosphere is the first that tests the accuracy of the weather forecast that was made eight days earlier to select targets for the Voyager narrow-angle camera. Three of the four targeted features are visible in this photograph; all three are close to their predicted locations. The Great Dark Spot with its bright white companion is slightly to the left of center. The small bright Scooter is below and to the left, and the second dark spot with its bright core is below the Scooter. The spacecraft was 6.1 million kilometers (3.8 million miles) from the planet at the time of camera shuttering.
The dark spot, Neptune’s most prominent feature is called the Great Dark Spot. It has a halo and streamers of white high altitude clouds. “Dark Spot 2” is at the lower right edge of the planet. Located slightly above and to the left of “D2” is the lighter “Scooter,” so named because of its rapid motion relative to other cloud features.
4. Cloud systems in Neptune’s southern hemisphere
5. The Great Dark Spot on Neptune is a storm system that rotates counterclockwise once every sixteen days. The Great Dark Spot is probably as large as the earth.
6. These High-altitude clouds over Neptune are called cirrus clouds. The brightness and shadows show that they are more than just a thin layer.
This Voyager 2 high resolution color image, taken 2 hours before closest approach, provides obvious evidence of vertical relief in Neptune’s bright cloud streaks. The bright sides of the clouds which face the sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun. This photograph was taken only 5,000 kilometers above the cloud tops, or about 3,000 Earth miles.
7. High thin clouds are swept around the planet Neptune by high winds.
This Voyager 2 image has been processed to obtain true color balance. The processing allows both the clouds' structure in the dark regions near the pole and the bright clouds east of the Great Dark Spot to be reproduced. Small trails of similar clouds trending east to west and large-scale structure east of the Great Dark Spot all suggest that waves are present in the atmosphere and play a large role in the type of clouds that are visible.
8. This false color image of Neptune was constructed to show the different levels of Neptune’s atmosphere.
9. This picture shows 2 dark narrow rings. It was a great discovery to find out that the rings are not uniform, but have bright spots as seen at the top. In the lower right is a portion of Neptune.
This Voyager image of Neptune gave us a lot of information that was not previously known because Neptune is so far away and some aspects of Neptune are hard to see. The rings are made of rocks that could be the size of a car or small truck.
10. Neptune’s largest moon Triton is made of solid ice and rock, and is the coldest place we know in the solar system..
In August 1989 Voyager 2 swept past Triton, a cold, bright moon where geysers spew ice particles into the think nitrogen atmosphere. Voyager 2 discovered six new moons and a number of rings around Neptune.
11. Triton is one of the large moons of Neptune. The image shows the contrast between the smooth floor terrain and the rough terrain found on this moon.
Triton has the coldest surface of any object the Voyagers observed, at -235 degrees Celsius (-390 degrees Fahrenheit). A receding ice cap covers the southern part of the moon. The upper regions are known as “cantaloupe terrain.” Dark streaks on the ice cap appear to be the result of nitrogen geysers rising 8 kilometers (5 miles) high. Prevailing winds carry dark particles toward the upper right.
12. This picture of Triton’s lake has been enhanced by a computer in order to emphasize the area which astronomers refer to as a volcanic caldera.
13. This view of Triton’s surface is approximately 300 miles across.
14. This shows the surface of Triton. Areas have been refloored by a melted liquid which hardened and left a smooth floor among the rugged terrain.
Lake-like features along the terminator record a time when these regions of
Triton's surface were fluid. This 200x200-km (124x124-mi) view was acquired
during Voyager 2's closest approach to Triton.
15. This is Neptune’s satellite 1989N1. The shape suggests it has been cold and rigid throughout its history and subject to much impact cratering.
16. This is a picture of Neptune and Triton as seen by Voyager three days after the flyby.
17. Neptune is the bigger crescent.
18. This picture shows the bright southern atmosphere of Triton.
Voyager 2 captured this image of Triton in August of 1989, while it was still
at quite a distance from the small Neptunian moon.
19. A view of Triton which offers little information regarding its surface.
20. Looking back at the Sun from the closest approach to Neptune.
PLUTO
1. Pluto is so far away there are few photos of it. This is a picture of Pluto and its moon, Charon.
2. Two pictures of Pluto and its moon Charon. On the left is a picture taken from Earth, and on the right is one taken by the Hubble Space Telescope.
