Understanding Habitable Zones

Understanding Habitable Zones
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Within our solar system, only Earth supports abundant life. This is largely due to a favorable distance from the Sun, vast amounts of water, gravity strong enough to hold a thick atmosphere, and a liquid-metal core that provides a magnetic field to shield us from solar flares. Whether life exists on planets around other stars depends on how often these same conditions occur. So it’s important for us to understand when and why Venus and Mars became so inhospitable.