It was one of the Earth's momentous times. Continents collided. Volcanoes erupted. Ocean currents shifted. Species ran amok.
Geysers spout up where a column of underground water is heated to boiling by "magma," or molten rock, pushing the water upward.
According to geologists, there's something very hot going on under all that ice.
Most of us take our oxygen-rich atmosphere for granted. Once upon a time, though, Earth's air was very different.
Scientists link fracking to the surge in earthquakes across the U.S.
If the earth keeps accumulating mass, does that mean that the Earth's gravitational pull has been increasing?
Scientists have found fossil evidence from tropical corals that existed at that time, and they have about 400 daily growth rings per year.
Canadian scientists studying water found deep in an underground mine have determined that the water is at least 1.5 billion years old, and maybe much older.
Scientists have a new estimate for the geological age of one of Mercury's oldest regions.
NASA's Curiosity rover has found evidence for life-supporting conditions on ancient Mars.