Earth’s marine species, especially those at the tropics, were in trouble again about 419 million to 365 million years ago. This series of mass extinctions during the Devonian period eventually ...

The planet's internal structure comprises four layers: a rocky crust on the outside, then a rocky mantle, an outer core made of magma and a solid inner core. This metallic inner core, about 1,500 ...

Earth is our home planet, and it's the only place in the universe where we know for certain that life exists. Earth formed over 4.5 billion years ago from a swirling cloud of gas and dust squished ...