Growing Earth’s oceans
One question that has baffled planetary scientists is how oceans formed on the surface of terrestrial planets like Earth — rocky planets made of silicate and metals. It’s believed that in additionzq to Earth, the terrestrial planets Mars and Venus may have had oceans soon after their formation. There is ample evidence to suggest that these planets formed from rocky clumps called planetesimals that later combined in high-energy collisions and left their surfaces covered in molten rock, or magma. It didn’t take long for these magma oceans to cool, and many researchers contend that oceans of water were created later on, when icy objects like comets and asteroids deposited water on the rocky planets.But a recent study by an MIT planetary scientist suggests that the planetesimals themselves provided the water that created oceans. As Lindy Elkins-Tanton, the Mitsui Career Development Assistant Professor of Geology in MIT’s Department of Earth, Atmospheric...