Today I'm talking about the Fermi Paradox in my astro-for-physics-majors class (and I'll talk about it again on Friday in my astro 101 class).
It's a really simple question with completely terrifying/mind-blowing implications, first asked by Enrico Fermi (who, ironically, was one of the Manhattan project scientists...)
Our universe is 13.8 billion years old, our Galaxy is at least 10 billion years old, other planets are surely much older than Earth, with more time to involve intelligent life.
"So where is everybody?"
A few possibilities for how to resolve the paradox. I'm going to list them all and put a poll at the end of this thread so you can vote for your favourite!
1. We are alone. We are the first intelligent life that has ever evolved in the Universe.
(Generally in astronomy any explanation that requires us to be special is a bad one. Then again, we are here asking this question, which is kind of the mother of all observation biases)
2. There are other civilizations out there, but they don't travel. This could be because it's just too hard (our furthest probe has traveled something like 0.004% of the distance to the closest star). Or maybe the drive to explore/colonize is a human trait and other intelligent life wouldn't have that drive.
3. The absolutely most depressing option: there are other civilizations, but technologically advanced civilizations just don't last very long, so the chances that we'd overlap with another civilization nearby and notice their presence is super unlikely.
4. A galactic civilization exists! But they are avoiding us, either because we're morally reprehensible, or because we're in a kind of "wildlife preserve" (though I find these ideas pretty weirdly human-centric...)
5. The only civilizations that survive long-term are the ones that realize that exponential growth is unsustainable, and completely reorient to a lower-energy state. This would make them undetectable to us.
(I talked about this idea a few days ago, with lots of interesting comments: https://mastodon.social/@sundogplanets/111478947136600731)
Which resolution to the Fermi Paradox do you think is best?
@sundogplanets My choice would be something like "don't travel" but I think that is quite extremist. We often assume that technology and science are like magic and once we get the proper knowledge we will be able to jump to other stars, kind of a subway, but AFAIK it is so hard to do that trip that we might be able to do it in the future only once per century or so. That means the probability of contact reduces a lot.
