Are we alone?
That's a big question. Huge. It's one of the biggest philosophical concept there is: Is there life elsewhere in the Universe?
Moreover, is there intelligent life? I'd be thrilled beyond measure if we saw the signature of, say, chlorophyll in the ice of Europa, but finding phytoplankton is a long way from having someone to talk to.
I've been asked if I think life exists elsewhere, and my answer is always that I do. This is based upon a single fact: Life got a toehold on Earth very rapidly after the planet formed, just a few hundred million years. That implies that it's easy for life to arise (a process called abiogenesis, life from non-life), because it happened so quickly as soon as conditions for it on Earth were present.
But we really don't know that. Maybe life usually takes billions of years, and we were lucky. We only have our one example of life arising and so it doesn't really tell us anything about how easy it is. All it tells us is that the chances of it happening are not 0.
A new study using a sophisticated form of statistical analysis shows that life is ...