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Published on Sep 15, 2014
The sun has two planets in its Goldilocks zone: the Earth and Mars. The crucial difference: a magnetic field that protects us from the sun’s radiation and makes liquid water - and life - possible on Earth. | For more How the Universe Works, visit http://science.discovery.com/tv-shows...
Catch all new episodes of HOW THE UNIVERSE WORKS Wednesdays at 9/8c on Science Channel!