Did the first inhabitants of the Earth originate from a primordial soup boiling in a primordial cauldron, or was the seed of life sown from space? Were we originally on Mars, how would we then come to Earth? Did the comet bring seeds with the elements necessary for life?
We have an excellent theory of evolution, but we do not have an acceptable theory of the origin of life. No one has ever, even experimentally, succeeded in turning inanimate matter into something alive.
We are only part of the last chapter of a story that runs for billions of years. How it all started is still unknown. It is possible that today’s oldest ancestors still rest in the biosphere, hidden in deep shadow. We may never find the answer to that question.