Where Are They? Nick Bostrum in the current Technology Review;What could be more fascinating than discovering life that had evolved entirely independently of life here on Earth? Many people would also find it heartening to learn that we are not entirely alone in this vast, cold cosmos.
But I hope that our Mars probes discover nothing. It would be good news if we find Mars to be sterile. Dead rocks and lifeless sands would lift my spirit.Conversely, if we discovered traces of some simple, extinct life-form--some bacteria, some algae--it would be bad news. If we found fossils of something more advanced, perhaps something that looked like the remnants of a trilobite or even the skeleton of a small mammal, it would be very bad news. The more complex the life-form we found, the more depressing the news would be. I would find it interesting, certainly--but a bad omen for the future of the human race.
How do I arrive at this conclusion? I begin by reflecting on a well-known fact. UFO spotters, Raëlian cultists, and self-certified alien abductees notwithstanding, humans have, to date, seen no sign of any extraterrestrial civilization. We have not received any visitors from space, nor have our radio telescopes detected any signals transmitted by any extraterrestrial civilization. The Search for Extra-Terrestrial Intelligence (SETI) has been going for nearly half a century, employing increasingly powerful telescopes and data-mining techniques; so far, it has consistently corroborated the null hypothesis. As best we have been able to determine, the night sky is empty and silent. The question "Where are they?" is thus at least as pertinent today as it was when the physicist Enrico Fermi first posed it during a lunch discussion with some of his colleagues at the Los Alamos National Laboratory back in 1950.[...]
From these two facts it follows that the evolutionary path to life-forms capable of space colonization leads through a "Great Filter," which can be thought of as a probability barrier. (I borrow this term from Robin Hanson, an economist at George Mason University.) The filter consists of one or more evolutionary transitions or steps that must be traversed at great odds in order for an Earth-like planet to produce a civilization capable of exploring distant solar systems. You start with billions and billions of potential germination points for life, and you end up with a sum total of zero extraterrestrial civilizations that we can observe. The Great Filter must therefore be sufficiently powerful--which is to say, passing the critical points must be sufficiently improbable--that even with many billions of rolls of the dice, one ends up with nothing: no aliens, no spacecraft, no signals. At least, none that we can detect in our neck of the woods.Now, just where might this Great Filter be located? There are two possibilities: It might be behind us, somewhere in our distant past. Or it might be ahead of us, somewhere in the decades, centuries, or millennia to come. Let us ponder these possibilities in turn. Originally posted May 7, 2008.
12 comments:
Rover been on Mars, 2 years now - There is no life out as we have known. Agree with this guy
http://physics.ucsd.edu/do-the-math/2011/07/galactic-scale-energy/.....And I am taking my grandchildren to see this
http://www.amnh.org/exhibitions/beyond/.....We will build space colony/city and probably a new species
Yeah, I read a lot Bostrom's papers back at the turn of the century or thereabouts. For me, it was Old Home, hello there old probability and statistics? How you doing these days? And though it is all well-reasoned and nicely laid out in that concise structured English boarding school style outline kind of thinking, the thing is, it's philosophy. It's great for ballparking shit, and, yes, Fermi problems, it ain't solid empirical data.
Here's a good example: http://www.3dgalaxymap.com/Features.html It's a great fucking app, that gives you hopefully sense the wholly unbeleivable and inhuman scale of what's involved in just our neck of the woods (if "neck" is a million light years). But dig, we still don't know if there are 200 billion, 500 billion, a trillion stars in the Milky Way. Best guess is the trillion mark. So, throw in the Rare Earth theorizing, Goldilocks zones, importance of Jupiter, a big Mars-sized rock named Thea colliding with the baby Earth to create a a good-sized rock with thin crust and abnormally large iron core for a nice electromagnetic shield, and an axis-stabilizing Moon, circling around what appears to be an extremely accommodating and well-behaved star, etc. etc. But you got only the one example, and a N=1 sample space don't tell you shit.
So, thanks for the figures, Nick, but as a one-time math wanker, I recognize the behaviors.
(Shorter version: It's Filters all the way up).
I don't understand him at all.
This galaxy is 100,000 light years in diameter. What if the average distance between between advanced civilisations is 10,000 light years? We have switched to cable and satellites sending TV signals down so it may be in another 200 years we stop broadcasting because it is so inefficient. So if other civilisations have gone through that phase then we could not detect them.
So assuming we could ever get up to 20% of light speed and we start spreading thru interstellar space, it could be hundreds of thousands of years before encountering another civilisation. And all of this alien attack business is mostly paranoid projection by European culture because that is what they did to everyone on this planet.
"What could be more fascinating than discovering life that had evolved entirely independently of life here on Earth? Many people would also find it heartening to learn that we are not entirely alone in this vast, cold cosmos."
I guess I would be among those who find it (somewhat) heartening. But only because the people who run this world are so depraved. There is no guarantee that the aliens would be any better. There is indeed an equal likelihood that they'd be worse. But at least the odds are 50/50. With madmen running the world, there is no chance at all. Fortunately, we don't seem to have a choice in the matter. Evidence points in that direction. I have no idea why making this simple observation is deemed outlandish, kooky and insane. But, waddayagonnado?
"The more complex the life-form we found, the more depressing the news would be. I would find it interesting, certainly--but a bad omen for the future of the human race."
You never explained why this was a bad omen.
"the evolutionary path to life-forms capable of space colonization leads through a "Great Filter," which can be thought of as a probability barrier."
There is no probability barrier. The Universe is big enough to accommodate any probability.There is only the spaces between probability. The Universe is so vast that it is almost certain that there is life elsewhere. I'm sure some mathematician somewhere can tell us the odds. Odds are life exists elsewhere in the Universe. The question is is it possible for the space between these islands of life to be bridged. And since time like space is endless I think it is quite reasonable to assume (yeah I know the joke) that life somewhere in the Universe has evolved prior to us and that this or even some of these older lifeforms has managed to bridge the gap between the islands of life that, in all probability, are scattered throughout the Universe.
My understanding is, although it is true that an alien Arecibo could detect an Arecibo sent signal pretty much on the other side of the galaxy, and we've only sent out two really strong signals detectable throughout the galaxy (one sent in the direction of the constellation Hercules, and so, in a few hundred years, expect a visit from the Herculoids:
http://www.youtube.com/watch?v=6NdcNw4gOFU ),
the majority of our noise is just that. All that radio, TV, telecomm stuff quickly degrades to random noise at about a few thousand AU out from Earth (most bounces off the ionosphere back to us). Couple that with the fact that we digitally pack it now, and you can't tell that it's not noise.
In any case, when you use a self-pleasuring (as in conjectural) number plugging into an equation like Ward and Brownlee's Rare Earth Equation,
http://en.wikipedia.org/wiki/Rare_Earth_hypothesis
It's hard not to end up with N=1, as in us. As I said, that first term in the equation, the number of stars in the galaxy, isn't even close to being pinned down, and the second term, the number of planets around a star in the habitable zone, contains about a dozen hidden assumptions at least (probably only single stars, that are F, G, or K, that are type I population or a little younger in metallicity, that happen to form in a relatively small cluster so that there is a robust planetary disk to start with, that happens to be a good distance from the galactic core, but not too far out, that manages to avoid supernovae in the spiral arms, and doesn't stare down the barrel of a gamma ray burst, etc. etc.), and then the fractions just keep multiplying downwards. To the point that I guessing the Rare Earth hypothesis is mostly right, but give it a few years, and we will have much, much better empirical data.
That's not to say we are alone, or that any of the other hundreds of excuses for why we experience the Great Silence, but the fact is, Fermi was right, we should be neck deep in aliens.
Bostrom's Doomsday argument and the self-selection phenomenon. Let's say I tell you that for the whole of humanity's existence, from species origin to extinction, that there have been in total 100 billion people that have lived. Where do you think you are in that line? Towards the beginning? Or the end?
And if, it turns out the doomsdays are inevitable for every species, intelligent or not, and you find evidence against sparse life, then chances are very, very, very good, that our version of Bostrom's Great Filter lies in our future, rather than something we fortunately whistled by sometime in our past.
But you know, Bostrom is naturally dour.
"The filter consists of one or more evolutionary transitions or steps that must be traversed at great odds in order for an Earth-like planet to produce a civilization capable of exploring distant solar systems."
That wouldn't necessarily mean that the civilization that reached that point would ever contact life on other planets. Let's say they acquired the capability of physically exploring the radius of a light year. That's minuscule. No there's another filter that needs to be passed before these beings can contact life on other planets. It would require a technology of a different order than what we know today. Based probably upon things we don't even know exist. All we're saying when we talk about the impossibility of interstellar travel is that we haven't the technology to do it. When we deny evidence of ET presence on earth, we are saying no one else does either. Sounds like hubris to me.
All we're saying when we talk about the impossibility of interstellar
travel is that we haven't the technology to do it.
No. The burden of proof isn't on those who point out the;
1. Great Filter statistical improbability
2. the energy
3. information
4. time/life hurdles
Involved with covering those distances.
When we deny evidence
of ET presence on earth, we are saying no one else does either.
Disbelief in ET presence on earth is a three-legged stool.
1. Complete lack of compelling artifactual evidence.
2. specific knowledge of intentional disinformation campaigns waged by the Nazi's, the Soviets, and the U.S. which was flooded with Nazi technology, propaganda, and intelligence assets at the end of WW-II.
3. specific knowledge of the recurrent and characteristic psychological underpinnings of "contact" experiences.
Sounds
like hubris to me.
The magical thinking required to dismiss all of the above and to anthropomorphize ET's into capricious human adolescents, playing chicken with human aircraft, abducting and probing humans, and vandalizing agricultural fields, seems considerably more hubristic to me.
What sounds like hubris to me...? with us not yet having passed through the great filter, that an alien civilization that has would even find us interesting. And, I would think if they had passed through The Singularity, we wouldn't even be able to recognize the manner in which they might have anally probed us.
Matter moving anywhere at an order of magnitude of 1/10 the speed of light or faster would require enormous amounts of energy to move even the smallest of interesting masses. Phuck that, I'd leave this mass behind.
John those who made animation and cartoons back then knew science and humor. If 15% population knows the connection to science and what is simulated; I would be shocked.
Methinkst the "aliens" are in our midst, and have been with us for as long as we have suffered from ponerological exploitation. Sexual abuse and psyops are very old instrumentalities of human livestock management. If you stop and think about it, there is a whole horrible underworld of mutilation and control prefigured by the Inquisition, which was itself prefigured by Rome, which was itself prefigured by Sargon's impalements, and so on, and so on, and so on...., how long and continuously this sadistic libertinage has gone on is anybody's guess.
Occulted/prohibited pharmacopia are very old instrumentalities of human livestock management. How has it come to pass that for 99% + there is no inkling of the entheogenic origins of..., and so on.
Reason examination of the Third Reich is exceptionally useful in this regard, is that it brings all of this mysterious side of human history and human governance into living-memory focus.
When I was younger there were three things that I dearly hoped I would never see in my life. One was a fail-proof lie detector, oye vey ist mir! We'd all be forced to show up at a police station every six months to prove our bonafides. After all, if you've got nothing to hide, then what's your objection, Jimbo? Another fear was unambiguous proof of intelligent life elsewhere in the universe, so much worse if they showed up and provided first-hand social intercourse. What a shit-storm that would be, religiously (for those so minded), culturally, socially, economically, a real game-changer, and not in a good way. I doubt if we're alone in the universe, but I hope that the illusion is maintained well into the future. I forget the third thing, it'll come back to me.
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