It’s becoming increasingly clear that there is alien life out there, in our solar system and beyond. To the extent that people still cling to the geocentric notion that Earth is the only planet in the universe capable of supporting life, it’s time to think again.
The latest indicator of that reality came yesterday, when NASA announced that its Cassini spacecraft had found promising signs that alien life may exist on Enceladus, one of the moons orbiting Saturn. Cassini flew through a plume that was spraying out of the icy shell covering Enceladus and detected molecular hydrogen. That’s a big deal because molecular hydrogen is created by interaction between warm water and rock, and along with carbon dioxide is the kind of food that early, microbial life forms can thrive on. Scientists believe that life on Earth may have started in the same kind of environment surrounding the deep geothermal vents in our oceans — and if life started here, why shouldn’t it also occur in the same environment elsewhere?
Does that mean that there is, in fact, some form of life already existing on Enceladus? Not necessarily, because the large amount of molecular hydrogen and carbon dioxide detected by the Cassini spacecraft suggests that there isn’t much, if any, bacteria or microbial life on Enceladus actually consuming the food — a fact that doesn’t surprise scientists, because they think Enceladus is relatively young and it takes a long time for life to emerge.
But equally intriguing is that NASA also announced that the Hubble telescope found evidence of similar plumes on Europa, a much older moon orbiting Jupiter. Because Europa has apparently been around for billions of years longer than Enceladus, the combination of molecular hydrogen, carbon dioxide, and time might have allowed life to gain a foothold there. It’s something we’re going to have to explore.