Where Did Our Oceans Come From?

For a planet with a surface that’s over 70% water, we still aren’t sure why we have so much of it.

Photo by Andrzej Kryszpiniuk

There are many possible explanations as to why we have water here on Earth, and yet every single one of them leaves unanswered questions. While more planets than just ours are thought to have held water a few billion years ago, Mars, Venus, and…