>>18674890No, there are things we only find on Earth as a cause of Atomic explosions. These isotopes do not exist naturally on Earth, that does not mean it does not occur naturally in the universe beyond this single planet.
As far as we know, plastics are entirely non-natural and man made. But if we suddenly discovered a polymer hydrocarbon on another planet, it doesn't necessarily follow that mankind was there and created it. It just means we have discovered something normal on one celestial body not normal to our own.
Also, jews.