Evolution is a product of a split from a common ancestor in response to change in environment.

Following that sequence backward to DNA itself, and the organic compounds that make up DNA, we assume that common compound ancestor was terrestrial.

What if terrestrial DNA came from organic compounds in comets during the Hadean bombardment? That suggests our organic compound origins may not be terrestrial, but from space, and it might explain why DNA is so different in molluscs, compared to insects, compared with reptiles, compared with mammals.

Could our human fascination and desire with space be in fact, a longing to "return home?"