Here’s a theory backed up with evidence. The universe is full of intelligent races but they never meet each other because the universe is really big and we can’t travel faster than the speed of light. Intelligent species are all pretty much stuck in the solar system they evolved in.
Pretty much what that crusty old giant of evolutionary biology Ernst Mayr expressed in Towards a New Philosophy of Biology. Or more pointedly, even if they aren’t stuck in their solar system entirely, the odds of a technologically advanced alien society and human society co-existing within a temporal framework that would make contact possible in absence of some sci-fi light+ speed travel is incredibly low.
I think the evolution of life somewhere out there is likely. We’re talking about a huge galaxy and I think if anything close to the Oparin Hypothesis is correct it shouldn’t be that crazily difficult. Sapience? Well, who knows how unlikely that is. But hard contact? Insanely, astronomically (heh) unlikely. In the incredibly remote chance SETI ever did scare up something it would just be the reflections from thousands of years ago of someone long dead.
Also this sapience would really find it handy (heh) to have some sort of manual abilities. Dolphins could be smart as hell…but they aint building a ship with snouts. Octopi have it going on there but…I’m sure there are some sort of evolutionary pressures at play. And hell…
…Maybe curiosity is super-rare too. Man is really good in the curiosity department and in the ‘need for approval/serotnin rush’ department.
But now im really rambling.
Dolphins may well be building ships soon enough. With their opposable thumbs.
We don’t know how long aliens live. The beings on Capella 4 may see a 10,000-year trip as an opportunity to binge watch and nap.
That’s quite a directive, that prime directive.
It’s unlikely. A species that would consider ten thousand years as an insignificant amount of time would have to have a lifespan of over a million years.
If a species has a million year lifespan, they’re either going to have an equivalently long breeding cycle. If they don’t have their first offspring until a hundred thousand years or more after birth, natural selection and evolution will be an incredibly slow process. The human race is about ten thousand generations old. Ten thousand generations for this theoretical long-living race would be about a billion years.
And humans didn’t just appear. We’re a link in a chain of prior species. Our long-living aliens must be the descendants of long-living animals. When would all of this evolution from single-celled organisms to space-traveling intelligent beings have occurred? The universe is only around thirteen billion years old.
Perhaps you’re suggesting these aliens have incredibly long lifespans but don’t have comparable breeding cycles. Maybe they start having offspring within a few years after birth. And then what? They continue have offspring for hundreds of millennia? Any species which did that would collapse from over-population. Their long-living animal ancestors would have gone extinct before evolving into an intelligent species.
But let’s wave all that away and just say it happens. They’re an incredibly long-living intelligent race that exists somehow.
We still wouldn’t see them. I mentioned before how the universe is really big. Let me be clearer; the universe is really really really really really really really really really really big. That long living intelligent alien that’s been traveling for ten thousand years? He’s not even a fraction of the way here yet. Let’s say by an amazing coincidence, he happens to be in the same galaxy we’re in. And let’s say he’s only halfway across this galaxy away from us. Assuming he’s traveling at the speed of light (which is impossible) he’s going to need a hundred thousand years to reach us.
And assuming this alien is in one of the other hundreds of billions of galaxies in the universe, he’ll never get here. The “local” group of galaxies (which contains over fifty galaxies) is over twenty million light years across. So even if this alien is here in the intergalactic neighborhood and is moving along at the speed of light, he won’t show up for millions of years.
I’m not an expert on this, so technical input would help-
Isn’t it true that we only see a fraction of planetary systems out there?
We are not looking in all directions.
The first methods of detection (Doppler shift) favored detection of giant planets with short orbital periods. These have to have orbital planes more or less aligned with us.
Occultation is better, but also favors detection of large planets. These MUST have orbital planes aligned with us.
I had thought that detecting ANY earth- sized planets in habitable zone (I think we’ve detected at least one) was pretty good.
So when are they going to build this hyperspace bypass I keep hearing about?
All that is true, and none of it relevant to the fact we haven’t found a single especially Earthlike planet. The random alignment of the exo-planetary systems relative to our own gives us a random sample of what is out there. And thousands of known planets seems like a pretty good sample size to give us a pretty good idea of what types of planets we should find in systems that aren’t aligned correctly or are in a different patch of the sky. If our sampling shows that Earthish planets must be Pretty Damn Rare for the thousands of stars we have looked at, it is pretty likely that they are equally Pretty Damn Rare for the rest of the stars of that type that we haven’t looked at.
Before we actually started discovering planets, some models of planetary formation claimed that our arrangement was typical, with small rocky planets close to the star and large gas giants far out. But the actual observations show pretty much any type of planet at pretty much any distance. So having a planet of the right size and the right composition at the right distance from the right type of star is a random roll of a whole handful of dice.
I dunno, this article suggests otherwise.
In about 45 minutes. Grab your towel and let’s head to the pub for 3 pints and a bag of peanuts.
Well, yes, but I was addressing your point about viewing angle and areas of the sky examined. And my point about the handful of dice still stands.
Try these articles
Barring something nuts like “The moon is actually a base for aliens and our leaders know all about it and thats why they shut off cameras on the ISS whenever a ship appears”*…
I think we have to accept that they have FTL travel. Hey…IFFFFFFF the craft we see in those ‘fighter craft follow UFOs clips’ ARE aliens. Well hell, they already exhibit impossible inertia-defying properties. Doesn’t mean they can go FTL of course, but if they’re doing one impossible thing already??? Yes i know its a stretch.
- What??? No one else owned The Big Book of Conspiracies??
Ummm…why?
I know you’re the OP but isn’t the topic of the thread theories why we don’t see aliens here on Earth? A limit of the speed on travel would explain it.
Or is your topic more along the lines of “Assume aliens visit Earth on a regular basis. Now come up with a theory to explain why we don’t see any evidence of aliens visiting Earth on a regular basis.”
The Forbes article is saying that there are probably more planets with life than we expect if we look only for earthlike ones, so that doesn’t quite support your argument.
The other one doesn’t quite explain how we managed to make it.
Do you have a cite saying that current techniques can find all sizes of planets at all distances from their stars?
You’re not reading about the really interesting conspiracies. A woman in my critique group thinks that UFOs are piloted by fallen angel lizard beings. Who came down here and are responsible for the theory of evolution.
She is also a flat-earther.
No. Do you have a cite where I made that claim?