Mercury Mercury is the closest planet to the sun. It is extremely hot on the side of the planet facing the sun and very cold on the other. There is no water on the surface. There is practically no atmosphere. The composition of Mercury is similar to that of Earth. The surface of the planet is covered by craters, most of which are very old. Planet Terrestrial none none 57,910,000 0.387 AU 69,800,000 46,000,000 0.2060 167 467-183 None Diameter () 4,878 0.055 0.054 0.378 Venus Venus, the second planet from the sun, has a very thick atmosphere made primarily of carbon dioxide. This atmosphere traps a lot of energy from the sun, so the planet is very hot. There is no water on the surface. The composition of Venus is similar to that of Earth. The surface of Venus is covered by lava flows and volcanic rock. Planet Terrestrial none none 108,200,000 0.723 AU 108,900,000 107,500,000 0.0068 457 484 377 Thick Diameter () 12,104 0.815 0.88 0.907 1
Earth Earth, the third planet from the sun, is the only world known to have life. The surface of Earth is constantly changing. Approximately three quarters of Earth s surface is covered by water. Earth has an atmosphere that allows some light from the sun to reach the surface but that protects the planet from harmful radiation. Planet Terrestrial one none 149,600,000 1 AU 152,100,000 147,100,000 0.0167 15 58-89 Moderate Diameter () 12,756 1 1 1 Mars Mars, the fourth planet from the sun, has a thin, mostly carbon dioxide atmosphere. The composition of Mars is similar to that of Earth. There is no obvious liquid water currently on the surface of Mars. However, surface features suggest that there might once have been liquid water on the surface and may still be liquid water below the surface. The planet has frozen carbon dioxide at its poles. The largest volcano in the solar system is on Mars. Planet Terrestrial two none 227,940,000 1.524 AU 249,100,000 206,600,000 0.0934-63 24-143 Thin Diameter () 6,794 0.10744 0.149 0.377 2
Jupiter Jupiter, the fifth planet from the sun, is the first gaseous planet in the system and the largest. As with the other gas giants, Jupiter is made largely of hydrogen and helium. The gases are in motion. This forms colored bands and eddies. For example, there is a huge storm, commonly known as the Red Spot, that has lasted at least 300 years. Planet Jovian 62+ one 778,330,000 5.203 AU 815,700,000 740,900,000 0.0484 Max Min -144-148 (cloud tops) Diameter () NA 142,984 317.82 1,316 2.364 Saturn Saturn, the sixth planet from the sun, is a gas giant. As with the other gas planets, Saturn is made largely of hydrogen and helium. Like Jupiter, Saturn has bands, eddies, and giant storms. Saturn is most famous for its rings. These rings are made of billions of pieces of ice, dust, and rock. Some pieces are the size of salt grains, others are house-sized. Planet Jovian 47+ seven main 1,426,800,000 9.539 AU 1,507,000,000 1,347,000,000 0.0542 Max Min -153-113 -180 NA Diameter () 120,536 95.16 755 1.064 3
Uranus Uranus, the seventh planet from the sun, is a gas giant. As with the other gas planets, Uranus is made largely of hydrogen and helium. Uranus has few visible surface features. It appears mostly blue. Like Saturn, Uranus has some rings. Planet Jovian 47+ seven main 2,870,990,000 19.191 AU 3,002,000,000 2,738,000,000 0.0472 Max Min -195-190 -215 NA Diameter () 51,118 14.371 52 0.889 Neptune Neptune is the eighth planet from the sun. (Note: Pluto is sometimes closer to the sun than Neptune is.) As with the other gas planets, Neptune is made largely of hydrogen and helium. There are bands or layers in the gases. Like Saturn, Neptune has some rings. Planet Jovian 13+ six 4,498,300,000 30.061 AU 4,542,000,000 4,452,000,000 0.0086 Max Min -204-200 -215 NA Diameter () 49,532 17.147 44 1.125 4
Earth s Moon Earth s moon is the second largest moon relative to its planet in our solar system. The composition of the moon is similar to that of Earth. The moon has no atmosphere. As a result, the surface temperatures vary widely. There is no known liquid water on the moon. The moon s surface is covered by craters, most of which are very old. Object Type Avg. Dist. from Earth Moon Terrestrial 384,500 Avg. Day Temp. ( C) Avg. Night -23 107-153 (equator) -233 (poles) None Diameter () 3,476 0.0123 0.166 Europa Europa is an icy moon of Jupiter. There is strong evidence to believe that a crust of ice about ten kilometers thick covers a deep ocean of water. Europa has practically no atmosphere. Despite this lack of an atmosphere, there are relatively few craters on the surface. Instead, the surface is covered with cracks. Object Type Avg. Dist. from Jupiter Moon Icy 671,000 Temp. ( C) -130 Thin, tenuous Diameter () 3,138 0.008 5
Titan Titan is the largest moon of Saturn. It has a thick atmosphere of 90-97% nitrogen, 3-10% methane, and other trace gases. The surface of Titan seems to have liquid methane, which flows over the surface like water does on Earth. Object Type Avg. Dist. from Saturn Moon Terrestrial 1,222,000 Temp. ( C) -179 Extensive Diameter () 5,150 0.024 Enceladus Enceladus, one of the moons of Saturn, has a high albedo, reflecting almost 100% of the electromagnetic radiation it receives from the sun. Geysers, probably heated from well within the moon, seem to be giving off jets composed mostly of small ice particles and water vapor. These geysers suggest that there may be liquid water within Enceladus. Object Type Avg. Dist. from Saturn Moon Terrestrial 237,948 Temp. ( C) -198 Minimal Diameter () 504 0.000018 6
Ceres In August 2006, Ceres, along with Pluto and Eris, was declared to be a dwarf planet by the International Astronomical Union. Ceres orbits the sun between Mars and Jupiter, within the main asteroid belt. It is the largest object within this belt. Object Dwarf Planet 414,000,000 2.77 AU Orbit Eccentricity Dimensions () 0.080-106 975 909 Eris In August 2006, Eris, along with Pluto and Ceres, was declared to be a dwarf planet by the International Astronomical Union. Eris, which orbits the sun out beyond the Kuiper belt, is actually larger than Pluto. It has at least one moon, which is visible in the image on this card. Surface temperatures on Eris vary between about 232 and 248 Celsius. Object Dwarf Planet 10,123,000,000 67.67 AU Orbit Eccentricity Diameter () 0.4418-243 about 2400 7
5 6 Pluto In August 2006, Pluto was declared to be a dwarf planet and not a classical planet by the International Astronomical Union. Pluto has a highly elliptical orbit that sometimes brings it in closer to the sun than Neptune. When Pluto is farthest from the sun, its atmosphere actually freezes. The dwarf planet is completely frozen all the time. 7 Object Type Moons Rings Dwarf Planet Icy 1 none 5,906,400,000 39.48 AU 7,381,000,000 4,447,000,000 0.248-225 -213-236 Tenuous Diameter () 2,247 0.0022 0.005 0.066 8 411