The Inner and Outer Planets in Our Solar System

by Elizabeth Howell April 23, 2014

Want to stay on top of all the space news? Follow @universetoday on Twitter In our Solar System, astronomers often divide the planets into two groups — the inner planets and the outer planets. The inner planets are closer to the Sun and are smaller and rockier. The outer planets are further away, larger and […]

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How Far Are The Planets From The Sun?

by Elizabeth Howell April 21, 2014

The eight planets in our solar system each occupy their own orbits around the Sun. They orbit the star in ellipses, which means their distance to the sun varies depending on where they are in their orbits. When they get closest to the Sun, it’s called perihelion, and when it’s farthest away, it’s called aphelion. […]

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The Planets in Our Solar System in Order of Size

by Elizabeth Howell April 21, 2014

If you’re interested in planets, the good news is there’s plenty of variety to choose from in our own Solar System.¬†From the ringed beauty of Saturn, to the massive hulk of Jupiter, to the lead-melting temperatures on Venus, each planet in our solar system is unique — with its own environment and own story to […]

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What Are These Hollows on Mercury?

by Fraser Cain March 26, 2014

Emily Lakdawalla from the planetary society describes one of the mysteries that’s currently fascinating her. There are strange structures on Mercury which have been called “hollows”. What might they be? Remove this ad Fraser Cain on Google+

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Mercury Shrinking: the First Rock from the Sun Contracted More than Once Thought

by Jason Major March 16, 2014

Whatever Mercury’s did to trim down its waistline has worked better than anyone thought — the innermost planet in our Solar System has reduced its radius* by about 7 kilometers (4.4 miles), over double the amount once estimated by scientists. Of course you wouldn’t want to rush to begin the Mercury diet — its planetary […]

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