Smallest: Pluto, then Mercury is next largest, then Mars, Venus, Earth. Largest: Jupiter, next a bit smaller is Saturn, then Uranus and Neptune. Jupiter is about 10x than Earth, and the Sun is about 10x bigger than Jupiter. Thus, the Sun is about 100x bigger than Earth).
Review of the Terrestrial Planets
MercuryIt takes a trained astronomer's eye to see that this is NOT the Moon! It's Mercury. The way you can tell is the moon has dark smooth patches, called Mare. Mercury has an entirely cratered surface. Mercury is not much bigger than the Moon. |
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VenusAt optical wavelengths, all one sees of Venus is its dense, smooth cloud cover. This image, taken in ultraviolet light, penetrates just a bit to show the shape of the clouds, which spin around the surface of Venus at 100 m/s. The surface Temperature is 890 F! |
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EarthNot too hot, not too cold. A perfect temperature for liquid water and life to develop. Moderate atmosphere which protects it from the solar wind, high energy photons and keeps the surface at a stable temperature. Has a massive moon! Probably created in a late-evolutionary stage, proto-planet collision. |
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MarsAfter Earth, the best place to live in the Solar System! Possibly had liquid water in its early history, which may have allowed life to develop. We don't think there is life there now. Lots of talk about terra-forming Mars, but it won't happen real soon! |
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