<Homer Simpson> Mmmm, alternate lifeforms… <Homer Simpson>
Minor nitpick to an otherwise excellent post: the Earth is “blue” (i.e. has an oxygen-rich atmosphere mostly transparent to visible light) because it has life, not the other way around. In fact, the atmosphere of the Earth during the original development of life was a reducing composition and any significant amount of free oxygen would have been toxic and corrosive.
I think UncleRojelio has summed it up best; even if life is common, and sentient life that is capable of something like industrial civilization is not infrequent, the timeframe for two comparable civilizations within a reasonable distance to overlap is astronomically thin. To put it in perspective, life has existed on Earth for an estimated 3.8 Byr; multicellular life for about 1 Byr; complex animals with anything like cognitive abilities for about 500 million years; primates for about 60 million years; modern humans for about 200 kyr; and a civilization capable of receiving and transmitting electromagnetic signals through interstellar space for about 80 yr. Even if we assume the development of life on other planets to proceed in an order and pace similar to that of humanity, the error band for developing the same level of technology would vastly dwarf the time we have had such technology ourselves. It is very easy to postulate developing the capability thousands of years ago, or retarding development through war or natural disaster to thousands of years in the future, not even accounting for any other variation in evolutionary development. Civilizations may grow, flurish, and disappear within tens of light years of each other without ever overlapping in any ability to detect one another. As TriPolar points out, the amount of even local space that we’ve been able to examine in any detail for signs of life is an immeasurable sliver. There could be lifeforms floating in the clouds of Saturn, or on Charon pumping Helium II blood though bodies powered by slight electrothermal differences between sun and shade, and we would not know about it.
There are other reasons that we may not be detecting existing civilizations. For one, space is very, very large, and discerning anything less than stellar levels of energy signals at a distance of more than a few tens of parsecs isn’t possible with anything like conventional technology. Forget about aliens on Barnard’s Star receiving episodes of I Love Lucy and *Gilligan’s Island[/I} (“Those poor people!”); such signals would not be distinguishable from the interstellar radio background at that distance even if the aliens could tease out the NTSC broadcast protocols. Another is that the technology of an alien civilization may not look anything like ours and be fundamentally incompatible (i.e. not using radio frequencies for communication). It may well be that such civilizations are wary of communicating or displaying their presence to the outside, or that a denser planetary atmosphere may prevent astronomy and space travel.
Another aspect needs to be considered. In space operas like Star Trek and Babylon 5, even highly advanced species are portrayed in a fairly facile fashion, like a particularly odd subculture of nerds; capable, perhaps, of defragniferating depleted dilithium crystals and distorting the space-time continuum with energy of pure thought, but mostly just a bunch of regular guys with a bad case of Treacher-Collins Syndrome. They speak some kind of language that is conceptually translatable to English, hang out in the holodeck, and make out with random lieutenants creating cross-species spawn that have a terrible time fitting in. The reality is that any sufficiently advanced civilization, like their technology, will be as indistinguishable from gods as we are to our domesticated pets. We would have little to say or relate to a human civilization 30 kyr ago even provided we could translate into uggra-unkh, and a completely alien civilization even a few thousand years ahead of us may regard us with even more disinterest. They may have no interest in finding or responding to us because we have nothing to offer other than a novelty to observe.
As far as the possibility that planetology and the development of life is limited to the same exact direction and rate as found on Earth, that is gross expansion of a single data set to cover the practical infinity of the cosmos. We can make some general speculations about the timeline of availability of heavy elements and some likely minimum rates at which necessary complexity can appear due to natural evolutionary processes, but beyond that we just have no data to insist that extraterrestrial life should develop at anything like the same time as our own.
Stranger
And to add to a perfect post by Stranger, I would also speculate that transmitting information via electromagnetic means is highly inefficient and exceptionally poor, due to speed of light concerns, over stellar distances. If communication is going on, I would speculate that advanced civilizations are using a different technology to get the word across. Television and radio are likely ignored as a medium of information exchange, except by a few species who are just barely on that tiny spot on the technology ladder where it is still useful. As an analogy, when was the last time you went to look for smoke signals? Or sent a telegraph across town?
If you mean that evolution is not like a 747 being assembled in a windstorm, you’re right. But the results and pacing of evolution is based on random events. The the asteroid had been displaced by just a few thousand miles perhaps reptiles would have developed intelligence long before mammals did, or perhaps they never would and mammals would still be just underfoot pests today. Given the incredible amount of lockstep development for the scenario in the OP to be true, this randomness is relevant.
To be fair to Star Trek, Roddenberry addressed the advanced civilization problem from nearly the beginning (Charley X, and then the Organians) but there is still the problem of why so many cultures are at nearly the same level.
Given that it is hard to have decent dramatic conflict when your combatants are a gladiator, a WW II soldier, a trooper from Starship Troopers, and a kid with a popgun, you can excuse them for ignoring the problem. However I’ve built a galactic history directly facing it, with my alien confederation having their own version of the Fermi paradox, that is, where are all the advanced civilizations?
Sure, it is a limitation of the genre. If every episode were like 2001: A Space Odyssey, with the characters incapable of taking any effective action for or against the any threat, it wouldn’t make for a very interesting show. But it doesn’t resemble the likely reality of extraterrestrial contact, which is far more likely to be like Rendezvous With Rama than Independence Day.
Stranger
Ok, but we’ll still be able to reproduce with other species, and have children that are half human, half Species 8472, right?
To the OP, my gut tells me that for whatever reason, we’re alone. Maybe we are the first: we’re the “ancient ones” who will leave behind some cool tech for some future species to utilize (like in Total Recall).
But, I can think of less depressing solutions to the Fermi Paradox.
Let’s say there’s a simple sidestep of relativistic limitations via something like hyperspace. And until a species becomes hyperspace-capable, they are subject to all the normal relativistic limitations and the more advanced species can’t be arsed to go that route.
This goes hand in hand with previous assertions I’ve made, that it is implausible that a very advanced species will desire conquest, and I doubt that our unique culture is as big a draw as star trek imagines it to be.
I haven’t encountered evidence of this second type of event, so I’m wondering what it would be. I’m sure that people have suggested the possibility, and it’s plausible, but what’s the evidence?
Does anybody believe that this was the result of a separate origin of life? If not, it doesn’t seem relevant.
THIS. It’s the vast distances that separate us from other possible extraterrestrials. So even if you find a life form that’s technologically advanced enough and gives a hoot about contacting us, it has to be close enough. Things are really far apart in the universe.
Are they all that far apart? A thousand years of travel between stars seems like a lot to us, but it isn’t that much for, say, self-replicating sentient robots. A properly advanced civilization, moving at sublight speeds, could easily fill up every corner of a galaxy within a few million years.
That’s the thing about Von Neumann machines - you only have to build one. So where are they?
The universe doesn’t support such complexity over the required timescale?
Von Neumann’s have to deal with entropy, just like everything else.
Willing suspension of disbelief. No stupider than the little man who gets entangled in an international conspiracy being able to take on hordes of well trained assassins.
Bowman, by the way, did take action against his immediate threat - HAL. After that, he was exploring. But I agree that it is a more accurate depiction of what a first encounter would really be like than any other.
That I’m not defending. Roddenberry seemed to have a fixation on human-alien mating (Spock was originally half-Martian) like his fixation on four-breasted women. I could almost believe Spock, being the child of very powerful parents. By TNG it was just silly. I might have given them a pass if they showed the children in the damn lab.
The one I use is that in a previous generation of civilization an advanced race visited a race about to kill itself, and nastiness ensued. Kind of like The High Crusade with real knights, not nice Poul Anderson knights. Therefore you strictly stay away from any culture who hasn’t invented star drive. If they blow themselves up, so be it.
On an individual basis, sure; but we’re talking about machines that replicate and evolve. Bacteria has existed on this planet for a billion years - I don’t see why these machines shouldn’t survive for that long.
I do that once or twice a year, with the reluctant assistance of retired CIA and MI6 comrades, a parrot sidekick, and an uncannily well-informed bartender named “Griff” who knows the exact name, current location, and favorite beverage of every living former East Bloc spy. You heard of that 2008 coup in Mauritania? Well, I don’t want to say to much, but let’s say that I was taking a hiking trip in some remote mountains when that occurred.
Yes, but Bowman was battling it out with his own tools, which had become essentially sentient and (almost) more powerful than him. Against the aliens, Bowman is helpless to stop them, or even comprehend what they are doing to him.
Stranger
I wonder if that is the case. Perhaps at some point we will decide that there are other ‘sentient races’ on our own planet.
We have a tendency to think that anyone who can’t communicate with us is inferior in some way. Even other humans, not just ‘animals’. But various animals on this planet may be considered to be ‘sentient’ at some level.
Example; For a long time “everyone knew” that humans were the only creatures with a sense of ‘self’. That was until some clever tests with chimps and mirrors demonstrated that they also have a sense of ‘self’.
I am not aware of any evidence whatsoever for multiple origins of life, let alone multiple extinction events that completely wiped out life in its entirety, causing it to start over. I can state confidently that belief in these things is not prevalent in the field.
You quoted ‘everyone knew’ so I assume you realize that this was not a universal view. Many people were able to observe a sense of ‘self’ in dogs, chimps, horses, and other intelligent animals. There was a tendency for people to develop philosophies that gave humans a special elevated position above all other animals.
If we encounter extra-terrestrial life, I am guessing that it is more likely to be like the unseen aliens of 2001 A Space Odyssey or a slime mold, than something similar to us. If we do find some life with human like intelligence and ability to manipulate the environment, its going to be disappointing if the only difference is pointy ears, or tentacles.
We might be lucky enough to live in the intergalactic equivalent of a game preserve. Most inhabitable planets in the universe get colonized by some other race before any indigenous species have a chance to develop intelligence. But our sun is in a galaxy that’s controlled by a race that has adopted strong enviromental protection policies. They discovered our planet millions of years ago but realized Earth had the potential to develop its own intelligent race. So Earth was declared off limits and the galactic power has prevented any other race from interfering here.