Mercury is the eighth largest planet in our solar system and the closest to the sun. Since this planet is so close to the sun it almost always is within 28 degrees of the sun’s temperature (Shehann 51). “In Roman mythology, Mercury is the god of commerce, travel and thievery” (Mercury 1). The planet probably earned this name because it moves so rapidly across the sky. Mercury has been known since the third millennium BC. Mariner 10 is the only spacecraft to visit Mercury; it flew by t

Saturn is the sixth planet from the sun and the second largest. Rings (or bands) are the classic distinction, which observers give to Saturn. “In roman mythology, Saturn is the god of agriculture” (Saturn 1). Galileo first discovered Saturn with a telescope in 1610. Pioneer 11 became the first spacecraft to visit Saturn in 1979, and now Cassini is on its way to visit in 2004 (Saturn 1). With a specific gravity less than that of water, Saturn is least dense of all planets. Like Jupiter, Saturn is about 75% hydrogen and 25% helium. Saturn’s interior is also similar to Jupiter’s consisting of a rocky core and a hydrogen layer, and some traces of various ices. Radiating more energy into space than it receives from the Sun, Saturn’s interior is hot 12,000 degrees Kelvin at the core (Saturn 2). From Earth, two prominent rings and one faint ring can be seen. Though they look continuous, the rings are actually composed of innumerable small particles each in an independent orbit. These rings range in size from a centimeter to several meters. Saturn has eighteen satellites, including: Pan, Atlas, Pandora, Janus, and many others. Along with the eighteen confirmed, six more recently discovered objects are being disputed as to whether or not they are satellites of Saturn. When it is nighttime sky, Saturn is easily visible to the naked eye.

Being the seventh planet from the Sun, it takes about 84 years for Uranus to make one orbit around the sun. While Uranus is the third largest planet in our solar system by size, Neptune is more massive (Uranus 1). Uranus’ summers are in complete sunlight, while the winters are covered with continuous darkness, each season lasting 21 years. Like other gas giant planets, Uranus has rings around it. The ten outer rings are dark, thin, and narrow, while the 11th ring is inside the outer ten and is broad. When Voyager II visited Uranus, in 1986, it discovered 10 small moons, in addition to the 5 large ones already known (Uranus 1). This has been the only spacecraft to visit Uranus. It is now known that Uranus has 21 moons, one of which was just recently discovered and does not yet have an official name. Uranus is the first planet discovered in modern times (1781), and had been seen many times before, but it was ignored as just another star (Uranus 2)! However, in contrast to Jupiter and Saturn, Uranus contains only very little hydrogen and is mainly composed of rock and various ices. The apparent blue color of Uranus is the result of absorption or red light by methane in the upper atmosphere (Baum 108). Uranus is barely visible to the naked eye on a very clear night, but is easily spotted with binoculars. After the discovery of Uranus, it was noticed that its orbit was not as it should be in accordance with Newton’s Laws. It was therefore predicted that another more distant planet must be disturbing Uranus’ orbit.

The second planet from the sun would be Venus. Thick swirling clouds cover Venus, which is named after the Roman goddess of love and beauty. Astronomers refer to Venus as Earth’s sister planet. Both are similar in size mass, density and volume. "In 1962 Mariner 2 became the first spacecraft to visit Venus” (Venus 1). Now this planet has been visited by more than 20 other spacecrafts; most recently the U.S. spacecraft Magellan that produced detail maps of Venus’ surface using radar. Venus is scorched with a surface temperature of about 235K during the day and 240K at night (Kopal 47). This makes Venus even hotter than Mercury. This high temperature is primarily due to a run away green house effect caused by the heavy atmosphere of carbon dioxide. Date from Magellan’s imaging radar shows that Venus probably once had large amount of water

Some topics in this essay:
Voyager II, Solar System, Jupiter Saturn, Pandora Janus, BC Mariner, English Earth, Earth Moon, Newton’s Laws, Moon Mars, Venus” Venus, solar system, planet sun, spacecraft visit, naked eye, roman mythology, visible naked eye, degrees fahrenheit, visible naked, “in roman mythology, 1 planet, largest planet, “in roman, planets solar system, spiritual gods world, looked spiritual gods,