In the late stages of the formation of Earth, the planet was a brutally hot, rough place. But perhaps not precisely in the way you might imagine.
Most renderings of that time show red-hot lava flowing around craggy rocks, with meteorites falling and volcanoes erupting. But according to those who study the time, the reality was rather different.
There was most likely no land much of the time, the medium to large meteorites arrived every few thousand years , and the surface was the consistency of a kind of room-temperature oil. Of course it was not oil, since this was a pre-organic time. Rather, it was mostly molten silicates and iron that covered the Earth in a “magma ocean.”
At its most extreme, the magma ocean may have been as deep in places as the radius of Mars. And it would have created thick atmospheres of carbon dioxide, silica dust, other toxic gases and later water vapor.
While meteor impacts did play a major role in those earliest days, the dynamics of the magma ocean were more determined by the convection currents of the super-hot magma (2000 degrees F and more), the high winds blowing above the surface, the steam atmosphere it often created and ultimately by the cooling that over hundreds of million of years led to the formation of a solid crust.
There is a burgeoning scientific interest in the magma ocean, which is expected to be part of the formation of any terrestrial planet and some lunar formations. The research focuses on the gaining an understanding of the characteristics and diversity of magma oceans, and increasingly on the potentially significant role it plays in the origin of life on Earth, and perhaps elsewhere.
The reason why is pretty simple: life (i.e., biochemistry) emerged on Earth from geochemistry (i.e., rocks and sediment.) Some of the earliest geochemistry occurred in the magma ocean, and so it makes sense to learn as much as possible about the very earliest conditions that ultimately led to the advent of biology.… Read more