Are humans from outer space? It doesn't have the ring of a good question, but bear with us. Of course, Homo sapiens didn't arrive on Earth in spaceships. We evolved here, from Homo erectus, about 200,000 years ago. Homo erectus, in turn, originated roughly a million years ago, solidly on Earth. So we have a long history on this planet. The thing is, we can't trace it all the way back to the beginning. The origins of life on Earth are shrouded in confusion, so much so that some scientists wonder — to other scientists' chagrin — if it started here at all.
Why Would Life On Earth Have Started ... Off Earth?
Tiny Interplanetary Hitchikers
Are Humans Just Aliens? Panspermia Explained
Key Facts In This Video
A small percentage of meteorites that have impacted Earth came from Mars. 03:15
Necropanspermia is the idea that organisms needn't be alive after traveling through space and arriving on Earth for their genetic material to influence the evolution of life. 05:34
NASA has to meticulously examine its equipment so that it doesn't inadvertently carry microbes into space. 06:55
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