Aliens - Are they out there? Have they visited us? And related questions

[Anomalocaris]

Is the money wasted on looking for life outside of Earth?

At the moment: yes. Also, set up some defenses and perhaps settle some new territory before you start seriously trying to find your neighbors. Scouting is not unimportant, but prioritize not being absolutely obliterated instantly, I should say.

Defense against a technological alien threat is a quixotic because given the multi-billion year timescale during which we and any alien life had to develop, the odds of us and an alien species being within a few decades of technological development so effective military defense is both needed and can plausibly be implemented is hundreds of millions to one. The only defense we can plausibly set up is defense against any alien microbes. But the odds that an alien microbe evolved in a different biosphere with a different biochemistry can infect humans or other life on earth also seems to be very low. So setting up defense is a complete waste of resources.

Given that we've ever even had pretense of technology for just a few hundred years out of our 3.9 billion year evolutionary history, the odds are if we encounter any technological alien, that alien would be would be thousands, millions, or even billions of years ahead of us. So the odds are if we can actually find a potentially threatening alien civilization, then that civilization had already known about us for a long time and haven't decided to obliterate us. If we are to find ourselves in conflict with an alien civilization that might be inclined to obliterate us, I think it's much more likely be an obliteration that will come like a bolt out of the blue from an more advanced alien who found us long before we would have found them.