Guy Threepwood
Mighty Pirate
It is, thank you very much.
Why would they have found earth? The galaxy is massive, there are untold numbers of stars, planets & asteroids for them to visit.
This is all true. But you are forgetting something. Namely, how radically different life even on our planet can be. There is a type of mold that is growing on the Chernobyl Sarcophagus. It feeds on ionizing radiation. Imagine something more complex than a mold who manages to do that. It would be utterly, completely alien and it would have no interest in finding 'us' because we do not consume the same things. Our needs would be radically different. There is also reason to believe that the spectrum of light visible to us need not be universal in other life.
Again, if you want to see aliens, look at the most radically different forms of life already here and imagine something even more different than that, because you and I would have more in common with a cabbage than with anything from another planet.
Different technological development?
Or, if you'll humour for a moment, perhaps we live in what amounts to a galactic 'nature preserve' of sorts. I mean is it really that strange to think that other sentient life might want to not-intervene with our development? Perhaps they(the aliens) have had a bad record regarding the 'uplifting' of life, and find it morally wrong to interfere until we've reached some level of technological & social advancement that would prevent us from losing our minds and deciding to fight them.
The galaxy is pretty big... but most is not too hospitable, if we detected a solar system which looked anything like ours, we'd be very curious, we'd certainly look for signals and probably send a probe- it would be extremely attractive real estate to anything close to our biology- which again is not an unreasonable assumption for sentient life.
The mold at Chernobyl is not having this conversation, and never will, extremophiles prove the point, that the conditions we developed in are those which make the best use of the inherent capacity of the universe for life, the same table of elements exists on Mars, but the conditions have to be just right. That we look for water as a sign for habitability on other planets is not a subjective, arbitrary condition, it's a uniquely life friendly habitat.. in ways that reflect the inherent chemistry of the entire universe.