The interiors of rocky planets and moons tend to be pretty hot compared with their surfaces. This heat, which can be caused by a number of sources — such as tidal stretching and compression, the ...

About 150 million years ago, a massive tectonic mega-plate stretched across the Earth, spanning roughly a quarter of the size of the Pacific Ocean. Its jagged contours ran all the way through the ...

Billions of years ago, Earth's surface was a sea of molten rock. As this simmering magma gradually cooled, it formed a continuous, rocky shell, with the denser minerals coalescing toward the planet's ...

Earth's surface is broken up into large plates that rub against each other, causing earthquakes, volcanoes and large mountain ranges. But how unique is our planet's geology? When you purchase through ...