Sun
Mercury
Venus
Earth
Moon
Mars
Jupiter
Europa
Io
Saturn
Titan
Uranus
Miranda
Neptune
Pluto
| equatorial radius: | | 6.05×104 km |
| polar radius: | same | ||
| mass: | 4.87×1024 kg | ||
| density: | 5.24 g/cm3 | ||
| shortest distance from sun: | 1.07×108 km | ||
| average distance from sun: | 1.08×108 km | ||
| greatest distance from sun: | 1.09×108 km | ||
| orbital eccentricity: | 0.007 | ||
| tilt of axis to orbit: | 2.12° | ||
| orbital inclination to ecliptic: | 3.40° | ||
| length of day: | 243 days | ||
| length of year: | 0.62 yr | ||
| temperature: | 455° C | ||
| atmospheric pressure: | 90.8 atm | ||
| atmospheric composition: | CO2 (96%), N2 (3%), H2O, Ar, CO, Ne, SO2 | ||
| satellites: | none |
Venus, fittingly named for the goddess of beauty, is the most brilliant of all the planets. It can often be seen even during the day. Ancient civilizations were awed by Venus; the Babylonians called the planet "Ishtar" while the ancient Chinese called it "Tai-pe." Both names symbolize light and beauty. The poet Homer described Venus as "the most beautiful star set in the sky," which is quite odd when you consider that Homer was thought to have been blind. Venus appears, as you can see in the picture above, as a clump of clouds. This is due to the planet's very dense atmosphere.
Venus in many ways is remarkably similar to Earth. Venus is nearly the same size (6,052 km radius) as Earth (6,378 km). Venus's mass is over 80 percent of Earth's, its density is only two percent different, and its gravitational pull is also close to our own. Venus's surface even has continents like ours, but it does not have shifting tectonic plates.
However, anyone who looks up into the sky through a telescope will notice that Venus doesn't look too much like Earth at all. No real continents are visible. In fact, the whole planet is blocked from view by its thick atmosphere. In the 19th century, speculation abounded that Venus was in fact inhabited by creatures more beautiful and perfect than ourselves. Stories and artists' depictions of these creatures appeared even in reputable scientific publications! Modern space exploration has, of course, disproved those old fantasies.
While Venus isn't really populated with perfect beings, its orbit is almost perfect. It has the roundest orbit of the nine planets. Its shortest distance from the Sun is almost equal to the longest distance. It takes longer for Venus to spin once around its axis than it takes the planet to revolve around the Sun. Translation: A day on Venus is longer than a Venus year! Oddly, the clouds in the atmosphere spin around much faster than the rest of the planet, taking about four Earth days to complete their spin around the planet.
And what about that thick atmosphere? It's made mostly of carbon dioxide (about 96%). The temperature on Venus is hundreds of degrees hotter than on Earth. Why is it so different from Earth? Basically, it can all be attributed to the fact that Venus is closer to the Sun than Earth is. Venus also has a huge greenhouse effect because of its carbon dioxide concentration. Venus serves as a reminder to us of what could happen if we continue to let our environment degrade.
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