Did we come from a comet?

Did we begin as organisms on a ball of ice and rock?

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Some scientists believe the beginnings of life originated from comets smashing into Earth. Image Credit: Philipp Salzgeber

Some scientists believe the beginnings of life originated from comets smashing into Earth. Image Credit: Philipp Salzgeber

Asked by Howard Bannister

There are theories that water and vital chemical building blocks of life may have been delivered to early Earth by icy comets.

How life first began on Earth is still one of the great mysteries. Liquid water is assumed to be essential for life, but it’s thought that there wasn’t any when Earth first formed. Delivery of this water by comet impacts may be the answer, as comets are mainly composed of ice.

Another vital component for life is amino acids, organic compounds that join together to form complex proteins. For a long time it was thought these molecules could only be created by biological processes, but how did they turn up on Earth?

Research has shown that the impact of comets on Earth may have brought these molecules with them. Alternatively, the impact may have provided the right conditions for these molecules to form some form of life.

We still don’t know for sure, but if these theories are true, it could be possible to say that our origins did come from comets!

Asked by Zoe Baily from the National Space Centre

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