All organisms are made of living cells. While it is difficult to pinpoint exactly when the first cells came to exist, geologists' best estimates suggest at least as early as 3.8 billion years ago. But ...

Earth is the only planet known to support life. Learn about what Earth is made of and where it came from. When you purchase through links on our site, we may earn an affiliate commission. Here’s how ...

In the whole history of Earth's climate, few events are as extreme as those that geologists call "Snowball Earth." "These are times when geologic evidence indicates Earth froze over, essentially from ...

The remains of a microscopic drop of ancient seawater has assisted in rewriting the history of Earth's evolution when it was used to re-establish the time that plate tectonics started on the planet.

Unfortunately, this book can't be printed from the OpenBook. If you need to print pages from this book, we recommend downloading it as a PDF. Visit NAP.edu/10766 to get more information about this ...

Over four millennia ago, in the final days of the Akkadian Empire in Mesopotamia, a drought swept over the region, afflicting lands as far away as Greece and what’s now Pakistan. Probably driven by ...