Earth's magnetic field was so weak it almost disappeared. Then, seemingly out of nowhere, complex life emerged.

Earth was once ruled by giant reptiles. Tyrannosaurus rex, the king of tyrant lizards, crushed bones. Spinosaurus hunted in rivers. Triceratops used horns for defense. Stegosaurus had plates and a ...

"You could pull up Google Earth images of places like Utah, zoom out, and you’d see the similarities to Mars." Though Mars, the Red Planet ... and drain into ancient lakes — possibly even ...

Mars, one of our closest planetary neighbors, has fascinated people for hundreds of years, partly because it is so similar to ...

Was Mars a dry and cold planet billions of years ago like we ... of Colorado Boulder investigated how conditions on ancient Mars could completely contradict what the Red Planet looks like today. This ...