Explore the Cosmos

The Solar System
Planetary Body	Origin in Mythology	Scientific Facts
	The Sun is personified in many mythologies: the Greeks called it Helios and the Romans called it Sol.	The Sun is by far the largest object in the solar system and is about 4.5 billion years old. Since its birth it has used up about half of the hydrogen in its core. It will continue to radiate "peacefully" for another 5 billion years.
	In Roman mythology Mercury is the god of commerce, travel and thievery. In Greek myth he is Hermes, the messenger of the Gods.	Mercury is the closest planet to the Sun and the eighth largest. It actually has a very thin atmosphere consisting of atoms blasted off its surface by the solar wind. Because Mercury is so hot, these atoms quickly escape into space.
	Venus is the goddess of love and beauty. The planet is so named probably because it is the brightest of the planets known to the ancients.	Venus is the second planet from the Sun and the sixth largest. Venus is sometimes regarded as Earth's sister planet. Because of their similarities, it was thought that below its dense clouds Venus might be very Earthlike and might even have life. But, unfortunately, more detailed study of Venus reveals that in many important ways it is radically different from Earth.
	Earth is the only planet whose English name does not derive from Greek/Roman mythology. In Roman Mythology, the goddess of the Earth was Tellus - the fertile soil.	Earth is the third planet from the Sun and the fifth largest. Earth is the only planet on which water can exist in liquid form on the surface. Liquid water is, of course, essential for life as we know it. It is also responsible for the erosion and weathering of the Earth's continents, a process unique in the solar system today.
	Mars is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet.	Except for Earth, Mars has the most highly varied and interesting terrain of any of the terrestrial planets. In the past there was clearly some sort of fluid on the surface, including large floods and small river systems. There may have been large lakes or even oceans. Early in its history, Mars was much more like Earth.
	Jupiter was the King of the Gods, the ruler of Olympus and the patron of the Roman state. Zeus was the son of Cronus (Saturn).	Jupiter is the fifth planet from the Sun and by far the largest. Jupiter is more than twice as massive as all the other planets combined. The gas planets do not have solid surfaces, their gaseous material simply gets denser with depth. What we see when looking at these planets is the tops of clouds high in their atmospheres.
	In Roman mythology, Saturn is the god of agriculture, and the father of Zeus (Jupiter).	Though they look continuous from the Earth, the rings are actually composed of innumerable small particles each in an independent orbit. The ring particles seem to be composed primarily of water ice. The ring systems are not stable and must be regenerated by ongoing processes, probably the breakup of larger satellites.
	Uranus is the ancient Greek deity of the Heavens, the earliest supreme god.	Uranus is the seventh planet from the Sun and the third largest. Uranus' blue color is the result of absorption of red light by methane in the upper atmosphere. There may be colored bands like Jupiter's but they are hidden from view. Like the other gas planets, Uranus has rings.
	In Roman mythology Neptune (Greek: Poseidon) was the god of the Sea.	Neptune is the eighth planet from the Sun and the fourth largest. Neptune's atmosphere changes rapidly, perhaps due to slight changes in the temperature. Like Uranus and Jupiter, Neptune also has rings,but their composition is unknown. Because of Pluto's eccentric orbit, Neptune is sometimes the most distant planet from the Sun.
	In Roman mythology, Pluto (Greek: Hades) is the god of the underworld.	Pluto is the farthest planet from the Sun (usually) and by far the smallest. Little is known about Pluto's atmosphere, but it probably consists primarily of nitrogen with some carbon monoxide and methane. For the majority of Pluto's long year, the atmospheric gases are frozen into ice.