Are we alone in the Universe? Given the size of the Universe and the countless stars, galaxies and potentially habitable planets, it seems inconceivable that there are no other life forms or civilizations out there. However, I took a intro to cell and molecular biology course last semester and I’ve just started to appreciate how difficult it is for intelligent life to evolve from simple cells. Therefore, I am of the opinion that we are alone in the Universe as a civilization and species because of the extreme randomness and luck required for intelligent life to evolve. I believe on other planets there may be simple cells or animal like species, but none of our intelligence that can develop technology, especially for space travel and inter-stellar communication. Does anyone else feel this way?
Somewhere, countless light years away, a being is thinking these same thoughts.
Actually it is normally the other way round: that so-called “simple” cells are actually pretty complex, and so this is usually the part that some people describe as so unlikely that we may be alone. The truth on that is, we don’t quite know yet. We already know that cells were not just spontaneously formed (e.g. how RNA likely became DNA, how mitochondria was captured etc), but there are still a lot of gaps. How likely cells are to form on an Earthlike world is still something we can speculate freely about.
But, once you have such cells, and a mechanism for passing on genetic variation, that’s all you need for a ratchet effect of increasing variation and specialization. It’s difficult for us to imagine complex animals coming about this way, but that’s just a failure of our imagination, because that’s exactly what happened, and it took mere millions of years, in a universe that’s been about for billions.
You haven’t actually talked about the Fermi paradox yet, not directly anyway, so I’ll wait for someone to open that.
Mijin: what is the exact Fermi paradox, which the OP overlooks?
I thought it was essentially, “With so many stars, why no contact?” What terms are we missing?
It isn’t really a paradox, of course, not formally. Just a conundrum. The more that we learn about the universe, the less unique we seem. Other stars, other planets, other atmospheres, other carbon chemistry… Did we just get lucky? Someone had to be first.
AIUI, the paradox states that if intelligent life is abundant, then some life forms must have developed interstellar travel. Even without FTL, the universe could be completely colonised in 100 million years. If that is so, then why hasn’t Earth been colonised?
Why should other civilisations want to build ships that will take hundreds, thousands, or tens of thousands of years to reach their destinations? Humans as we are now have only been around for what… 200,000 years or so? Might not be worth it to them to reach our neck of the woods. Or arm of the spiral, or whatever. Or maybe Earthlings just happen to be the most advanced species that has evolved. Or maybe we were colonised billions of years ago via directed or engineered panspermia. Or maybe we’re it.
At this point, I think we have insufficient data for a meaningful response.
Insufficient data! How long have we actually KNOWN that there are extra-solar planets.
It would only take one other intelligent species somewhere to prove that you are wrong. But they could be a thousand galaxies away, or only 30,000 light years. That is about equally distant with current technology.
psik
If we’re the first intelligent species, we better get cracking on universal colonialism before somebody beats us to it.
Right. I’m just saying the paradox is something more specific than the OP. It’s not whether ET intelligent life exists, it’s why no evidence of it here.
Now, indeed, one solution to the paradox is that such ET life has never evolved. But if we just have a debate in this thread about whether such life could evolve we’re not really taking on the paradox because even if hypothetically we agree such life is likely, there’s still the paradox.
Never been too convinced by the cost / patience argument. We’re already pretty much at the point where we could launch something that drift indefinitely and survive re-entry to another earthlike world for millions of dollars, not billions. And we are real newbs at this, just over a century ago we didn’t have planes.
I definitely do agree with this.
Many years ago, I watched, at the Los Angeles Zoo, as a Greater Kudu labored, completely pointlessly, to lever up a fallen branch with his horns, and shove it over the fence of his enclosure. It was just something to do. For us, putting the first Luna impacters on the Moon was very little removed from this behavior.
If we could spray-paint Kilroy Was Here on the surface of one of the planets of the next-nearest solar system, we would!
(Excerpted from longer post)
I suspect you’re absolutely right on this count, if we could, we almost certainly would do that, or something along those lines anyway. I don’t think, however, that we can accurately predict what any other life-form might or might not do by projecting our own proclivities upon them. Whatever form intelligent life might take out there, if it exists at all, probably won’t be very much like us. That burning need to explore every nook and cranny, and to expand , then expand, then expand again might be as unique to us as our sapience appears to be at this point.
Perhaps I presume too much, though, and you didn’t mean it that way. My apologies if I’ve misconstrued your remarks.
We can’t accurately predict, no, but we can speculate on what things seem more likely based on what we know.
Traits such as curiosity, and (for want of a specific verb) “trying shit out” seem like useful traits for a sentient species to have. Because they can communicate, or at least repeat useful actions, so relatively small observations / discoveries can have big benefits for the individual or group.
Now, of course, sending probes out of their star system is something unlikely to benefit the individual or group. But neither is most of current human space exploration. We do it because we have the hard-wired behaviours of curiosity and trying-shit-outing-ness.
The most accurate answer is that we don’t know how difficult it is for life to evolve to intelligence, and we won’t know until we go look.
However, I will say that in the view of many biologists, myself included, calling it “extreme randomness and luck” is probably not very accurate. There are good reasons to believe that complex systems may naturally gravitate toward complex, but not chaotic, “life-like” patterns of behavior. I always recommend the book “At Home in the Universe” by Stuart Kauffmann as a good representation of this point of view, though it’s pretty old by now. I need to look up some more recent research one of these days.
‘Experimentation’. 
Seeing as how a lot of the universe is billions of light years away, I don’t see how this could possibly be true. Perhaps you meant that the galaxy could be completely colonised in 100 million years?
Of course, if an alien civilization had gotten an earlier start before inflation had made the universe quite so big, sure, but then that gets us into some interesting questions. We evolved on a planet around a third-generation star with plenty of heavy elements. Is this necessary? Our planet took hundreds of millions of years to cool off enough to support any life, and then billions of years to move beyond the single-cell phase. Is this necessary? Could this have been sped up? Given some basic assumptions (extrapolated from the one data point we have, of course), are there any models of the minimum amount of time it would require for a civilization to appear?
100% agree.
Here are some very rough numbers that are pertinent to the subject. Based on exoplanet discoveries so far by Kepler and other instruments, out of the 200 billion stars in our galaxy, it appears that somewhere between 11 and 40 billion host potentially habitable earthlike planets, and well over a hundred billion more that are not presently considered habitable. That’s at least 11 billion planets in this galaxy alone on which life could form, and there are an estimated 170 billion galaxies in the universe. These individual numbers are so large as to be beyond our comprehension, let alone the product of those numbers.
To suggest that this one planet circling an average star in a distant corner of the galaxy is the only place in the entire universe on which life formed seems to me to be the kind of collectively self-centered myopia that is just breathtaking in its hubris, exactly on a par with the ancient belief that we were the center of the universe and all the stars and galaxies in the universe were basically just decorations in the sky for our amusement.
My own take on it is that not only is such a condition impossible, but it’s likely that given enough time, life will eventually form virtually everywhere that life can form, and that’s an awful lot of places.
The reason we’re not getting daily visitors from other planets – and indeed almost certainly never have – is just the sheer scale of the universe. Indeed, given intrinsic speed of light limitations it’s possible that contact between interstellar civilizations is exceedingly rare; it’s even possible that it’s never happened and never will. This is a far cry from the intergalactic civilizations of science fiction, but probably more realistic. One might even speculate that there’s some underlying purpose to such an arrangement of cosmic segregation, or at least that it’s a fortuitous happenstance.
As for why SETI has never detected any sign of intelligent radio communication, that’s a less obvious speculation. We ourselves have only been emitting radio communications for barely more than a century, which signals haven’t gotten very far at all, so to the vast majority of the galaxy there is no intelligent life on earth. It may also be that radio communication is only a short-lived technology before something much better comes along. Or it may be, as some have speculated, that civilizations themselves tend to be short-lived – perhaps once they discover nuclear power.
People used to talk about when Alpha Centauri and further points would receive our TV signals. There are a lot fewer to receive even now, and even less in twenty years when broadcast TV goes away in favor of cable and satellite, which gets pointed down. Plus TV, and now some radio, is getting to be digital, which will be harder to decode than analog. And when it is all internet there will be nothing broadcast at all.
Anyone beaming signals out will probably beam directed signals, not spray it all over the universe, and will beam them to potentially habitable planets. Maybe we just aren’t close enough to any civilization doing this - why beam them 1,000 ly away when there are lots of candidates 100 lys away.
I believe there are perhaps 20 advanced civilizations within our galaxy. Of those, only 5 have mastered interstellar travel. Of those, only 2 had the desire and resources to spread throughout the galaxy. One of those developed interstellar space fever and went extinct long ago; the other isn’t due to arrive in our neck of the woods for a few more eons.
I believe there are perhaps 1000 advanced civilizations within our local galactic group. Of those, 250 have mastered interstellar space travel; but only 5 have mastered inter-local-galactic group space travel. Of those, only 2 had the desire and resources to spread throughout the local group. One of those developed inter-galactic space dropsy and went extinct long ago; the other isn’t due to arrive in our neck of the woods for a few more millennia.
I believe there are perhaps 1,000,000 advanced civilizations within our Virgo Supercluster. Of those, 250,000 have mastered interstellar space travel. Of those, 5,000 have mastered inter-local-galactic group space travel. Of those, only 5 have mastered extra-local-galactic group space travel. Of those, only 2 had the desire and resources to spread throughout the supercluster. One of those developed inter-non-local galactic space diarrhea and went extinct long ago; the other arrived on Earth 68 million years ago, but quickly boogied out of the Milky Way with their tails between their legs when they got a load of the dinosaurs.
All the real action takes place in some of the other superclusters. Word has it that the Pisces-Cetus Supercluster is virtually crawling with advanced civilizations with a zest for travel, hearty immune systems and plenty of pesos to finance long trips. Those galaxies know how to rock and roll! We Virgo Clusterians are wimps by comparison. Unfortunately, we have zero chance of ever meeting a Pisces-Cetus Superclusterian. Why? Because I believe there really is an absolute speed limit in our universe; that there are real limits to the distances anything short of light can possibly travel to—wormholes and other modes of space-time manipulation be damned. We can go far, but we can’t go everywhere.
Intergalactic space travel may be the limit, or inter-supercluster space travel may be the limit, but, I’m confidant that at some order of magnitude shy of infinity, there is a limit.
A bit facetious…maybe (and my margin of error may exceed 1- 2%:)), but it illustrates my view of the inherent limitations of the spread of civilizations throughout the universe. As I see it, there has not been enough time (~14-billion years) or possible number of advanced civilizations capable of traveling to our galaxy to assure extra-terrestrial contact of any kind.
YMMV
I say we start leaving monoliths. *Eldritch *monoliths.
Because the Universe is big place. There could be millions upon millions of spacegoing civilizations and they could still never bump into each other. The Universe is a BIG place.
But, that’s no fun without any natives to colonize! 