With more and more exoplanets being discovered every day, scientists need to define a better idea of the “Goldilocks Zone”, that is an area that’s not too hot, not too cold and just right for life. And in the new definition, Earth just barely fits in.
The familiar map of Earth looks like it does in part because of the fact that the Earth spins, which more or less evenly distributes the water across the surface. If the Earth had no spin, most of the ocean water would pool near the poles, leaving the equator region high and dry.
One day, a long long long time from now, the Sun will expand to many times its current size, engulfing the inner planets, including our own Earth, vaporizing our atmosphere and rocks and trees and cute baby deer. What will that look like? Some astronomers at Washington University St. Louis decided to find out.
As vast and deep as the oceans look to us, compared to the rest of our rocky planet, our mighty oceans are but a thin skin of water . In the above illustration from the USGS above, you can see that all of Earth’s water, if condensed into a single ball, would only be half as wide as the US. Europa on the other hand, has quite a bit more. There goes the sci-fi stories about aliens invading Earth to get our precious water.