Space Events

Giant Impact That Formed the Moon Blew Off Earth's Atmosphere

The moon came into existence after several planet-size space bodies smashed into the nascent Earth one after the other, with the final one actually forming our satellite, while several impacts repeatedly blew off our planet’s atmosphere, according to a new study.

Until now, scientists thought it was unlikely that the early Earth could lose its atmosphere because of a giant moon-forming impact. But the new research, based on recent studies showing that at its infancy our planet had magma oceans and was spinning so rapidly that a day was only two or three hours long, argues that this may have been possible.

That research argued that the moon is actually a giant merger of bits and pieces of our own planet, partially destroyed by a catastrophic collision with a space body 4.5 billion years ago.

Back then, the Earth had a two- or three-hour day, she said, and the impact made it throw off enough material to coalesce into what became our satellite, making it the Earth’s geochemical twin. [How the Moon Evolved: A Video Tour]

This ultra-rapid spin is one of the important conditions necessary to make the atmospheric loss theory work, Stewart said.

The other criterion is the presence of terrestrial magma oceans — and this hypothesis has now got support thanks to new data obtained from volcanoes.