Which planet is most similar to Earth? (Intermediate)

I was just curious; What planet is most like Earth. In composition, size, in atmosphere, etc?

Venus and Mars are the most like Earth, but in different ways.

In terms of size, average density, mass, and surface gravity, Venus is very similar to Earth.

But Mars is the planet that is most similar to Earth in other ways. A Martian day is just over 24 hours, and its rotation axis is tilted by about the same amount as Earth's. Most interestingly, however, it is thought that at some point in Mars's past, it may have had liquid water on its surface, just as Earth does now. This leads some people to suspect that Mars may have once harbored life.

About the Author

Christopher Springob

Christopher Springob

Chris studies the large scale structure of the universe using the peculiar velocities of galaxies.  He got his PhD from Cornell in 2005, and is now a Research Assistant Professor at the University of Western Australia.

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