A weathered sign in the Minnesota River Valley proudly proclaims: “World’s Oldest Rock.” Erected in 1975, it marks a 3.8-billion-year-old gneiss — or so scientists thought.

This paper will take you as far back in the climate record as is currently possible, to the Archean Eon, from 3.9 to 2.5 billion years ago (Bya ... crust existed so early in Earth’s history ...

The order of the planets in the solar system, starting nearest the sun and working outward, is the following: Mercury, Venus, Earth ... formed about 4.6 billion years ago from a giant rotating ...

The Midcontinent Rift is a giant tear that formed in what is now the U.S. Midwest 1.1 billion years ago. Nicknamed North America's "broken heart," it is filled with solidified magma and lava.

High in Canada’s Rocky Mountains, the animals of an ancient ecosystem can be seen battling for life. The fossils of the Burgess Shale offer a glimpse at the incredible diversity of early life on ...