Comment on Either the aliens have listed Earth as a no-contact planet or we are probably alone in the universe.
Cocodapuf@lemmy.world 15 hours agoAnd even if they could, it’s hard to imagine a reason to travel to another star system.
The expansion of a species beyond a single star system for any reason is dubious, there’s really just no reason to do it, and the cost is extremely high (given known physics).
I say there’s no reason to leave the solar system, but I think that probably needs some explanation, because the obvious reason that may come to mind is probably overpopulation on earth and looking for other habitable planets. The thing is, in order to travel to another star system you need to really master surviving in space; if you can build a colony ship, you can build space habitats. If you can build space habitats, then you have enough material and energy right here in the Sol system to support quadrillions of humans living in space habitats. In other words, there’s no reason to leave for tens of thousands of years.
All that is to say, if you aren’t traveling to other star systems for your own species, you probably aren’t doing it for others.
BananaTrifleViolin@piefed.world 13 hours ago
If we built a self replicating probe and sent it to the nearest system, and from there it sent off 2 more probes and so on, in 2 million years they’d have reached every system. The only cost would be the initial probe. and any species that has mastered it’s own star system could do that. They could send out their own genetic material and spread their form of live.
They don’t have to go themselves out into space, they can send automated machines. We’ve already started doing just that with very basic machines for scientific curiosity. I see no reason why we wouldn’t send out replicating probes when we have the technology to do it.
However we do come back to Fermi’s Paradox: the universe is 13800million years old. So far we have no evidence a probe has reached our star system. Where are they? Maybe we just haven’t stumbled across one yet. Or maybe life really is very rare?
Cocodapuf@lemmy.world 7 hours ago
Well there are actually some pretty convincing explanations for for the Fermi Paradox. The one I like most is that despite the 13800 million years, we’re pretty early for complex life, and we may just be the first technological civilization in the Milky Way.
The theory goes that while there are a lot of older stars out there, there aren’t a lot of 3rd generation stars. When some stars get to the end of their life, they collapse and then go supernova, leaving behind a dust cloud in which other stars can then form. Here’s the thing, many heavy elements are only produced through nuclear fusion during a supernova. (Basically everything heavier than iron, about 3/4 of the periodic table). So that second generation of stars contain more heavy elements within the star. When the second generation goes supernova, more heavy elements are created.
Life exists on earth thanks to all of the complex chemical reactions that can take place on earth. But all that may only be possible because we’re a 3rd generation solar system with all our fancy heavy elements, and 3rd Gen star systems are relatively new, we’re quite early on the scene.
So because of that, we’re certainly an early civilization, and we might be… the first.
Pixel_Jock_17@piefed.ca 12 hours ago
But on our planet we find life everywhere with even the most harshest of climates still teeming with life. I’d say we will (if we haven’t already) found alien life in microbial organism form.