“Well you run and you run to catch up with the Sun but it’s sinking,
racing around to come up behind you again.
The Sun is the same in a relative way but you’re older,
shorter of breath and one day closer to death.” –Pink Floyd
For the last four-and-a-half billion years, the Earth has spun on its axis, orbiting its parent star: our Sun. Today, our home planet looks something like this.
(Image credit: Reto Stöckli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA GSFC.)
Looking at our world, even from outer space, you see some very familiar features that we think of as essential parts of our world. The vast, watery oceans. Our substantial (but not too thick) cloud-filled atmosphere. And the great land masses: our continents. These continents are, perhaps, the most striking feature to a traveler looking down on our rock from space, as the land on our world is not merely the color of the rock that composes it or the ice frozen upon it.