Where Earth Got Its Water
A new theory shows Earth’s water was more locally sourced than ever thought before. The post Where Earth Got Its Water appeared first on Nautilus.
When Carl Sagan famously called Earth the “pale blue dot,” he was judging a book by its cover. Even though three quarters of our planet’s surface is covered by oceans, our planet is actually very dry. Water makes up about one part in a thousand of Earth’s mass (most of it is simply rock and iron). I say “about” because we don’t know exactly how much water is trapped in Earth’s interior. Estimates range from less than one “ocean”—defined to represent the sum of all of Earth’s surface water (oceans, lakes, glaciers, and so on)—to more than 10. Regardless of the exact water budget, Earth is about 10 times drier than crackers (which typically contain about 2 percent water).
