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Stretching the Search for Signs of Life
by Dennis Overybye
Reposted from:
http://www.nytimes.com/2007/10/11/science/11seti.html?_r=1&ref=science&oref=slogin
Call it a small step for E.T., a leap for radio astronomy.
Astronomers in Hat Creek, Calif., are planning today to switch on the first elements of a giant new array of radio telescopes that they say will greatly extend the investigation of natural and unnatural phenomena in the universe.
When the Allen Telescope Array, as it is known, is complete, it will consist of 350 antennas, each 20 feet in diameter. Using the separate antennas as if they were one giant dish, radio astronomers will be able to map vast swaths of the sky cheaply and efficiently.
The array will help search for new phenomena like black holes eating each other and so-called dark galaxies without stars, as well as extend the search for extraterrestrial radio signals a thousandfold, to include a million nearby stars over the next two decades.
Today, 42 of the antennas, mass-produced from molds and employing inexpensive telecommunications technology, will go into operation. "It's like cutting the ribbon on the Nina, the Pinta and the Santa Maria," said Seth Shostak, an astronomer at the Seti Institute, in Mountain View, Calif., who pointed out that this was the first radio telescope ever designed specifically for the extraterrestrial quest.
The telescope, named for Paul G. Allen, who provided $25 million in seed money, is a joint project of the Radio Astronomy Laboratory of the University of California, Berkeley, and the Seti Institute. "If they do find something, they're going to call me up first and say we have a signal," Mr. Allen said in an interview, adding, "So far the phone hasn't rung."
Describing himself as "a child of the 50s, the golden age of space exploration and science fiction," Mr. Allen, a founder of Microsoft, said he first got interested in supporting the search for extraterrestrial intelligence after a conversation 12 years ago with Carl Sagan, the Cornell astronomer and exuberant proponent of cosmic wonder.
When the idea later arose to build a telescope array on the cheap, using off-the-shelf satellite dish technology and advanced digital signal processing, Mr. Allen was intrigued. "If you know anything about me," he said, "you know I'm a real enthusiast for new unconventional approaches to things."
Telescopes, including radio telescopes, have traditionally been custom-built one-of-a-kind items. The antennas for the Allen array are stamped from a mold. Mr. Allen's family foundation put up the money to get the first part of the array built, with other contributions from Nathan Myhrvold, formerly of Microsoft and the chief executive of Intellectual Ventures in Bellevue, Wash., among others.
Leo Blitz, director of the Radio Astronomy Laboratory, estimated that it would take three years and $41 million more, depending on the price of aluminum, to complete the array. The full array, astronomers say, will be useful not just for science, but also as practice for a truly giant telescope known as the Square Kilometer Array, which would have a combined receiving area of a square kilometer and which astronomers hope to build in Australia or South Africa in 10 or 20 years.
Dr. Blitz said the main advantage of the Allen array for regular radio astronomy was the ability to obtain images of large swaths of the sky, several times the size of the full moon, in a single pointing. At low frequencies, he said, the full array could map the entire sky in a day and night and do it again the next night.
"This has not been possible before," he said.
In its partial form, Dr. Blitz said, the array is already almost as fast, and much cheaper to run, than larger telescopes.
The speed should make it possible to catch transient events, like radio bursts from colliding black holes, that might last only a few hours, while the mapping ability should enable astronomers to search for lumps of gas without stars, the so-called dark galaxies predicted by the prevailing models of cosmology.
The search for extraterrestrial intelligence has lived on the kindness of strangers since Congress canceled a NASA-sponsored search using existing radio telescopes in 1993, only a year after it had begun. The Seti Institute, which was to have conducted a search of nearby stars under contract to NASA, raised money from Silicon Valley and revived the search as Project Phoenix, using existing radio telescopes.
Project Phoenix was finished three years ago, having checked some 750 stars for signals, Dr. Shostak said. While that might sound like a lot, he said, "it doesn't impress anybody who knows how many stars there are in the galaxy."
There are some 200 billion stars in the galaxy, and a significant fraction of them have planets. Estimates of the number of intelligent civilizations in the galaxy have ranged from one (or none, if you are particularly discouraged about human affairs) into the millions.
Dr. Shostak calculated that the full Allen array would be able to detect a signal from as far as 500 light years that is only a few times more powerful than what can now be sent by the Arecibo radio telescope, a 1,000-foot-diameter dish in Puerto Rico that is the world's largest (although it is in danger of being shut down to save money). That translates to about a million stars, which he said was getting into a promising number. Dr. Shostak described the expanded search as looking for the needle in the proverbial haystack with a shovel instead of a spoon.
Anyone out there and broadcasting, for whatever wacky alien reason, would also have to be broadcasting right at Earth. But advanced civilizations, Dr. Shostak said, would be able to tell there was life on Earth because of the oxygen in our atmosphere.
"We've been broadcasting that for 2.5 billion years," he said.
The first thing Dr. Shostak and his colleagues plan to do with the newly operational 42-antenna array is to survey a strip across the center of the galaxy. There will be several billion stars in the field of view, but they will be very far away, 10,000 to 50,000 light years, so any signal would have to be huge to be detected. But who is to say that among galactic civilizations there are not a rare few with tremendous capabilities?
"I've never begrudged aliens any power in their transmitter," Dr. Shostak said.
http://www.nytimes.com/2007/10/11/science/11seti.html?_r=1&ref=science&oref=slogin
Call it a small step for E.T., a leap for radio astronomy.
Astronomers in Hat Creek, Calif., are planning today to switch on the first elements of a giant new array of radio telescopes that they say will greatly extend the investigation of natural and unnatural phenomena in the universe.
When the Allen Telescope Array, as it is known, is complete, it will consist of 350 antennas, each 20 feet in diameter. Using the separate antennas as if they were one giant dish, radio astronomers will be able to map vast swaths of the sky cheaply and efficiently.
The array will help search for new phenomena like black holes eating each other and so-called dark galaxies without stars, as well as extend the search for extraterrestrial radio signals a thousandfold, to include a million nearby stars over the next two decades.
Today, 42 of the antennas, mass-produced from molds and employing inexpensive telecommunications technology, will go into operation. "It's like cutting the ribbon on the Nina, the Pinta and the Santa Maria," said Seth Shostak, an astronomer at the Seti Institute, in Mountain View, Calif., who pointed out that this was the first radio telescope ever designed specifically for the extraterrestrial quest.
The telescope, named for Paul G. Allen, who provided $25 million in seed money, is a joint project of the Radio Astronomy Laboratory of the University of California, Berkeley, and the Seti Institute. "If they do find something, they're going to call me up first and say we have a signal," Mr. Allen said in an interview, adding, "So far the phone hasn't rung."
Describing himself as "a child of the 50s, the golden age of space exploration and science fiction," Mr. Allen, a founder of Microsoft, said he first got interested in supporting the search for extraterrestrial intelligence after a conversation 12 years ago with Carl Sagan, the Cornell astronomer and exuberant proponent of cosmic wonder.
When the idea later arose to build a telescope array on the cheap, using off-the-shelf satellite dish technology and advanced digital signal processing, Mr. Allen was intrigued. "If you know anything about me," he said, "you know I'm a real enthusiast for new unconventional approaches to things."
Telescopes, including radio telescopes, have traditionally been custom-built one-of-a-kind items. The antennas for the Allen array are stamped from a mold. Mr. Allen's family foundation put up the money to get the first part of the array built, with other contributions from Nathan Myhrvold, formerly of Microsoft and the chief executive of Intellectual Ventures in Bellevue, Wash., among others.
Leo Blitz, director of the Radio Astronomy Laboratory, estimated that it would take three years and $41 million more, depending on the price of aluminum, to complete the array. The full array, astronomers say, will be useful not just for science, but also as practice for a truly giant telescope known as the Square Kilometer Array, which would have a combined receiving area of a square kilometer and which astronomers hope to build in Australia or South Africa in 10 or 20 years.
Dr. Blitz said the main advantage of the Allen array for regular radio astronomy was the ability to obtain images of large swaths of the sky, several times the size of the full moon, in a single pointing. At low frequencies, he said, the full array could map the entire sky in a day and night and do it again the next night.
"This has not been possible before," he said.
In its partial form, Dr. Blitz said, the array is already almost as fast, and much cheaper to run, than larger telescopes.
The speed should make it possible to catch transient events, like radio bursts from colliding black holes, that might last only a few hours, while the mapping ability should enable astronomers to search for lumps of gas without stars, the so-called dark galaxies predicted by the prevailing models of cosmology.
The search for extraterrestrial intelligence has lived on the kindness of strangers since Congress canceled a NASA-sponsored search using existing radio telescopes in 1993, only a year after it had begun. The Seti Institute, which was to have conducted a search of nearby stars under contract to NASA, raised money from Silicon Valley and revived the search as Project Phoenix, using existing radio telescopes.
Project Phoenix was finished three years ago, having checked some 750 stars for signals, Dr. Shostak said. While that might sound like a lot, he said, "it doesn't impress anybody who knows how many stars there are in the galaxy."
There are some 200 billion stars in the galaxy, and a significant fraction of them have planets. Estimates of the number of intelligent civilizations in the galaxy have ranged from one (or none, if you are particularly discouraged about human affairs) into the millions.
Dr. Shostak calculated that the full Allen array would be able to detect a signal from as far as 500 light years that is only a few times more powerful than what can now be sent by the Arecibo radio telescope, a 1,000-foot-diameter dish in Puerto Rico that is the world's largest (although it is in danger of being shut down to save money). That translates to about a million stars, which he said was getting into a promising number. Dr. Shostak described the expanded search as looking for the needle in the proverbial haystack with a shovel instead of a spoon.
Anyone out there and broadcasting, for whatever wacky alien reason, would also have to be broadcasting right at Earth. But advanced civilizations, Dr. Shostak said, would be able to tell there was life on Earth because of the oxygen in our atmosphere.
"We've been broadcasting that for 2.5 billion years," he said.
The first thing Dr. Shostak and his colleagues plan to do with the newly operational 42-antenna array is to survey a strip across the center of the galaxy. There will be several billion stars in the field of view, but they will be very far away, 10,000 to 50,000 light years, so any signal would have to be huge to be detected. But who is to say that among galactic civilizations there are not a rare few with tremendous capabilities?
"I've never begrudged aliens any power in their transmitter," Dr. Shostak said.
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Posted: Saturday, October 13, 2007 | PermalinkComments 1 - 50 of 64 |
Reload Comments | Back to Top | Page Numbers2. Comment #78604 by Teratornis on October 13, 2007 at 6:49 pm
Well, everything we can extrapolate from our own technological progress (especially Moore's law) is that if any other technological civilizations have evolved before us, they (or their robot progeny) should have overrun the entire Milky Way galaxy by now. It would be an extraordinary coincidence indeed if some other civilization capable of broadcasting to Earth should have synchronized its evolution with ours so precisely that we should just now arrive in the comparatively brief million-year-ish window between its ability to broadcast and its conquest of the galaxy. I read a whole book of proposed explanations for the Fermi Paradox, and they all had a theological ring to them. The only explanation for the Fermi Paradox that makes sense is, we are alone in our light cone.
I wouldn't mind being proven wrong, but I don't think tax money should be spent on SETI any more than it should be spent on perpetual motion machines.
A much better cause for wealthy billionaires to bankroll would be figuring out how to use technology to eliminate all unnecessary physical travel, particularly of the petroleum-fueled variety (which accounts for most physical travel these days). However, not many "children of the 1950's" will grasp that concept. We may have to wait for the next generation of billionaires to retire.
References:
http://en.wikipedia.org/wiki/Fermi_Paradox
http://en.wikipedia.org/wiki/Moore%27s_law
http://en.wikipedia.org/wiki/Retro-futurism
http://en.wikipedia.org/wiki/Self-replicating_spacecraft
http://en.wikipedia.org/wiki/Peak_oil
Other Comments by Teratornis
3. Comment #78606 by roach on October 13, 2007 at 7:10 pm
Teratornis,How do you know of this short million yearish window between the ablility to broadcast and the conquest of the galaxy? I don't doubt that this may very well be possible if humans were afforded the opportunity to continue as we have for the last 40,000 years or so. But who's to say that it isn't more likely that we destory ourselves or the evironment makes the conquest of the galaxy impossible?
Other Comments by roach
4. Comment #78627 by Ick of the East on October 14, 2007 at 12:00 am
Well, everything we can extrapolate from our own technological progress (especially Moore's law) is that if any other technological civilizations have evolved before us, they (or their robot progeny) should have overrun the entire Milky Way galaxy by now.
When I extrapolate our technological progress, I see future humans spending all of their time in virtual worlds, not in stuffing themselves into tin cans and traveling to other gravity wells.
It has started already, and will only continue to grow as those worlds become more real and then go far beyond reality.
Other Comments by Ick of the East
5. Comment #78630 by Teratornis on October 14, 2007 at 12:41 am
In reply to comment #78606 by roach:
How do you know of this short million yearish window between the ablility to broadcast and the conquest of the galaxy? I don't doubt that this may very well be possible if humans were afforded the opportunity to continue as we have for the last 40,000 years or so. But who's to say that it isn't more likely that we destory ourselves or the evironment makes the conquest of the galaxy impossible?
The million-year window represents an estimate of how long it will take for humans or perhaps more likely their self-replicating robot progeny to overrun the Milky Way galaxy, barring some catastrophe (for us; anyone we might overrun might not view our demise as a catastrophe). I'm not suggesting this conquest is by any means guaranteed to happen. Instead I'm talking about the time window for two civilizations evolving in different planetary systems to communicate with each other by radio. SETI projects are looking for civilizations that are advanced enough to have built powerful radio transmitters, but they haven't been at that stage of advancement long enough to send their hordes of exponentiating robots to us (because Earth has not been overrun with them yet).
With respect to the Fermi Paradox (did you read the Wikipedia article I referenced above? Just about every thought we could have on this topic has already been hashed to death), two civilizations would have to evolve in highly improbable near-lockstep for both of them to arrive at the radio-communicating stage at the same time, before one or the other sends its robots in an expanding wave that reaches the other civilization. The maximum time window looks to be around one million years if the two civilizations are at opposite ends of the galaxy, and much less if they are closer. This assumes no science-fiction breakthroughs such as faster-than-light travel, just an extrapolation of technology we have now. The main trick is to build a (hopefully small) robot that can land on another planet (or asteroid, etc.), collect energy and raw materials to build more copies of itself, and after a century or so, they have created enough industrial capacity to launch ships with more probes to adjacent star systems. 0.1c looks like an attainable expansion velocity without needing to overturn our current understanding of physics (although of course no existing spacecraft goes anywhere near that fast).
The Milky Way galaxy is billions of years old (much older than the Earth), and we know no other civilization has evolved to a level of advancement more than one million years ahead of us (otherwise Earth would be crawling with their robots). Thus if there is anybody broadcasting signals to us, that would require an improbable coincidence, for the timing of our respective evolutionary schedules to be so close.
This was something the early SETI researchers did not take into account. They assumed the galaxy would be teeming with ETIs around a fraction of stars that would basically stay put for a long time, and communicate with each other by radio. That's a reasonable assumption for organisms like us, who could not live long enough to survive an interstellar journey at 0.1c. But long voyages would be no problem for much tougher robots. And once robots can replicate themselves autonomously and build spacecraft, the exponential explosion would begin.
In contrast to the apparently low probability of complex life leading to technological civilization, the probability of unicellular life on other planets may be rather high. Our robots may discover lots of bacteria as they expand into the otherwise uninhabited Milky Way. See:
http://en.wikipedia.org/wiki/Rare_Earth_hypothesis
Note that the Fermi Paradox represents the available facts, and the Rare Earth hypothesis is just one of many ways to account for it. Without the Rare Earth hypothesis, it is necessary to explain why none of the presumably many older extraterrestrial civilizations have unleashed an exponentiating robot horde that would have already overrun Earth.
And note that it wouldn't take an entire civilization to unleash the robots. Such capability might eventually be in the hands (or claws, or tentacles) of individuals or small groups of individuals in a sufficiently advanced civilization, just as today on Earth individual malicious computer users can unleash viruses. For an advanced civilization to contain its potential robot explosion would require it to be far more disciplined than homo sapiens has ever been.
Other Comments by Teratornis
6. Comment #78631 by Teratornis on October 14, 2007 at 12:56 am
In reply to comment #78627 by Ick of the East:
When I extrapolate our technological progress, I see future humans spending all of their time in virtual worlds, not in stuffing themselves into tin cans and traveling to other gravity wells.
Quite possibly, but it only takes one self-replicating robot to initiate the exponential robot population explosion. This is directly analogous to the founder effect in biology, whereby just one breeding pair has to raft onto an island, and if food and habitat are available, soon they found a whole population.
Personally, I doubt that humans in their present form will be interested in spending decades if not centuries in space to reach the nearest star, but for robots those time scales will be no problem.
The trick is to have a robot capable of replicating itself in a variety of planetary environments. That obviously requires technology far beyond what exists now, but we can anticipate having it if Moore's law holds up for enough decades.
Currently it takes a massively complex industrial economy to produce something as complicated as a robot. But that is largely because humans aren't that smart yet. We have to use large-scale processes to mine and smelt metals, etc., and we need millions of minds to specialize in different skills because no one person (let alone one computer) is smart enough to learn all the skills necessary to build a robot from raw materials.
But once computers become that smart, and nanotechnology enables machines to basically eat rocks, then self-replicating robots will be easy. Each one will carry around with itself the entire accumulated know-how of the human race. At the moment, only a fraction of this know-how is in writing and susceptible to be encoded for computers to use. But as time goes on, computers will get access to more of it, because computers are very cheap compared to humans, and getting even cheaper at a staggering rate.
Other Comments by Teratornis
7. Comment #78638 by Ick of the East on October 14, 2007 at 1:57 am
Quite possibly, but it only takes one self-replicating robot to initiate the exponential robot population explosion.
Agreed. But you are going on the assumption that robots need planets just as present-day humans do. (You said that robots would have overrun Earth by now.) But what in the world would they need worlds for? There is plenty of matter around without having to deal with planetary gravity wells and atmospheres.
If mech civilizations do exist, I would say there is a possibility of finding them out there somewhere, without them ever having visited Earth.
Other Comments by Ick of the East
8. Comment #78644 by steve99 on October 14, 2007 at 3:17 am
I read a whole book of proposed explanations for the Fermi Paradox, and they all had a theological ring to them. The only explanation for the Fermi Paradox that makes sense is, we are alone in our light cone.
I totally agree. There was an excellent summary of this situation by Stephen Baxter in his book Deep Future.
All kinds of excuses seem to be made about why ETs can't be seen, but they seem to be to be special pleading.
For them to be out there and for us not to see them...
All other civilizations would have to decide to stay at home and not travel.
All other civilizations would have not to send out robotic probes.
All other civilizations would have to restrict their energy use, and not start building Dyson spheres or harvesting the energy of stars in other ways (we could detect the signatures of such processes even for relatively distant stars in out galaxy)
and so on.
The search of ET is beginning to sound to be like the search for God... "He is out there, but he is invisible". I would love to be proved wrong.
Agreed. But you are going on the assumption that robots need planets just as present-day humans do. (You said that robots would have overrun Earth by now.) But what in the world would they need worlds for? There is plenty of matter around without having to deal with planetary gravity wells and atmospheres.
Not really, at least not in interstellar space. Robots would need to get close to stars for energy. I agree it would make more sense to harvest asteroids than planets, but that harvesting would be easily detectable.
Other Comments by steve99
9. Comment #78646 by Ick of the East on October 14, 2007 at 3:39 am
Robots would need to get close to stars for energy. I agree it would make more sense to harvest asteroids than planets, but that harvesting would be easily detectable.
Would it? With present technology? I suppose, but then I wonder if AI mechs, once intelligent enough, wouldn't rather hang around their own virtual world creations rather than overcome the physical one.
As an semi-intelligent being myself, I know what I would rather do.
Other Comments by Ick of the East
10. Comment #78649 by steve99 on October 14, 2007 at 4:16 am
Would it? With present technology?
Yes, or at least that is my understanding.
I suppose, but then I wonder if AI mechs, once intelligent enough, wouldn't rather hang around their own virtual world creations rather than overcome the physical one.
As an semi-intelligent being myself, I know what I would rather do.
But that that virtual life still requires energy. And unless they impose population control, that energy requirement will grow. Of course, any intelligent life will have to impose population control at some point. But even so, even virtual life would be wise to spread to more than one star, just to ensure long-term survival. This should be pretty easy for virtual life, as it can just be suspended until the journey is over.
Other Comments by steve99
11. Comment #78650 by Ick of the East on October 14, 2007 at 4:45 am
But that that virtual life still requires energy.
Yes, of course. So to get your eggs out of one basket, spread out around several hundred or thousand brown dwarf stars. They are very stable and last for for many billions of years.
After that, all the multiplication can take place in your virtual universes - even in virtual universes within virtual universes.
You will remain small and unseen, and there will be little or no need to communicate with other groups around other stars.
Other Comments by Ick of the East
12. Comment #78653 by steve99 on October 14, 2007 at 5:31 am
Yes, of course. So to get your eggs out of one basket, spread out around several hundred or thousand brown dwarf stars. They are very stable and last for for many billions of years.
Sure, but seems a bit of a waste to ignore those big hot starts first...
You will remain small and unseen, and there will be little or no need to communicate with other groups around other stars.
Why bother to remain small and unseen?
Sorry - I am being deliberately contrary here, just to illustrate that answers to Fermi's Paradox usually involve special assumptions.
Other Comments by steve99
13. Comment #78654 by Ick of the East on October 14, 2007 at 5:40 am
Why bother to remain small and unseen?
Seems the obvious choice to me. You don't know what's out there. Or maybe you do, which makes it an even better choice.
And big hot stars are less stable and tend to burn out fast and blow up. That's no good if you want a virtual eternity.
Other Comments by Ick of the East
14. Comment #78655 by steve99 on October 14, 2007 at 5:53 am
Seems the obvious choice to me. You don't know what's out there. Or maybe you do, which makes it an even better choice.
Ah.. but that is what I am saying. It is obvious to you. But you are human. Something else may be obvious to a hypothetical Klingon, or Borg :)
And big hot stars are less stable and tend to burn out fast and blow up. That's no good if you want a virtual eternity.
Actually, stars in general are not that good. What you want is really big spinning black holes - they give you lots of energy. So, if I was a civilization planning for the long term, I would be using up the energy of those big hot stars to make black holes...
Other Comments by steve99
15. Comment #78659 by Ick of the East on October 14, 2007 at 6:24 am
Ah.. but that is what I am saying. It is obvious to you. But you are human. Something else may be obvious to a hypothetical Klingon, or Borg :)
I don't know, but I would think that "Don't get eaten," is probably a Universal value.
You remember a lot of people were upset with the plaque that was put aboard Voyager, showing the location of Earth.
Other Comments by Ick of the East
16. Comment #78660 by steve99 on October 14, 2007 at 6:26 am
I don't know, but I would think that "Don't get eaten," is probably a Universal value.
In that case, there must surely be some 'eaters'. So why aren't they here, eating us?
Anything that might even want to eat us (or anything else) could easily and economically have launched self-replicating probes, that could have spread through the whole galaxy perhaps a thousand times over....
Other Comments by steve99
17. Comment #78663 by Ick of the East on October 14, 2007 at 6:42 am
In that case, there must surely be some 'eaters'. So why aren't they here, eating us?
They went virtual too! And the circle is complete!
Other Comments by Ick of the East
18. Comment #78676 by bluebird on October 14, 2007 at 8:56 am
foxfire, thanks for the reminder about SETI@home :) Looks as tho it's still running; albiet with a few glitches of late:http://setiathome.berkeley.edu/
Other Comments by bluebird
19. Comment #78678 by steve99 on October 14, 2007 at 9:05 am
They went virtual too! And the circle is complete!
OK, so all you really need is really good firewall software on your alien version of 'Second Life'....
OK, I'm sold! :)
Other Comments by steve99
20. Comment #78681 by roach on October 14, 2007 at 9:37 am
After reading the posts this seems to be a topic where no one knows what the hell he is talking about.Other Comments by roach
21. Comment #78713 by Rational_G on October 14, 2007 at 12:52 pm
I love these armchair philosophers here, who, by their briiliant analysis, have already decided that there is no intelligent life elsewhere in the galaxy. The only honest answer is that we simply do not know. The energy costs of moving across the galaxy are much greater than most people imagine. The ETs just might decide it's not worth the cost. Or they may prefer to keep, for the most part, quiet. Anyway it's all speculation!Are we going to be like the ancient Greeks, and decide everything by rhetoric? Or will we continue in the spirit of Galilleo, and perform the experiment?
The only intelligent thing, the only scientific thing, the only rational thing, is to perform the experiment and do the search!
We will only enrich ourselves in the process.
Other Comments by Rational_G
22. Comment #78722 by Teratornis on October 14, 2007 at 2:03 pm
In reply to comment #78713 by Rational_G:
I love these armchair philosophers here, who, by their briiliant analysis, have already decided that there is no intelligent life elsewhere in the galaxy. The only honest answer is that we simply do not know.
I'm more of a deskchair philosopher at the moment, and actually the honest answer is they simply are not here. That's the Fermi Paradox. Any civilization capable of sending radio messages to us is probably at most a few hundred thousand years from overrunning us. Given the vast age of the galaxy, it's unlikely we would be getting radio messages without already having been overrun.
The energy costs of moving across the galaxy are much greater than most people imagine.
As are the costs of broadcasting enough radio signals to blanket enough stars to get some chance of a reply. That doesn't discourage people from spending millions of dollars to listen for such signals.
The ETs just might decide it's not worth the cost. Or they may prefer to keep, for the most part, quiet. Anyway it's all speculation!
It's speculation which runs counter to what we know about the exponentiating nature of life. We have more than just one example; we have millions of species to observe, and all of them appear eager to expand into every habitat they can occupy. Any form of life which might voluntarily restrain itself will simply be overrun by another form of life which does not.
Of course, it may be possible that every alien life form which is advanced enough to broadcast interstellar radio signals has managed to perfectly quarantine itself against biological or robotic expansion. But it only takes one sufficiently advanced replicator to set off the exponential explosion. And if survival is the goal, as it seems to be for all life, it would seem that existing in more places makes survival more likely than existing in few places, so it's hard to see why a rational species would choose to hold back.
So is that a bet we want to take? Is that how you would spend your billion dollars? You can't think of any other more promising lines of research?
Are we going to be like the ancient Greeks, and decide everything by rhetoric? Or will we continue in the spirit of Galilleo, and perform the experiment?
We are performing the experiment, just by being here. Do you not understand the implications of the Fermi Paradox? We have already ruled out the overwhelming fraction of potential ETIs. SETI researchers are scouring painstakingly for the tiny improbable remainder, those ETIs who just happened to beat tremendous odds and gain radio technology before robot technology at just the time we have, along with ETIs which have managed to perfectly quarantine their exponentiating tendencies.
Note that if ETI's evolved according to a process of mutation and natural selection, they must have had the same billion-year history of exponential reproductive capacity that our ancestors did.
The only intelligent thing, the only scientific thing, the only rational thing, is to perform the experiment and do the search!
Only if you purposely ignore opportunity costs. Spending resources looking for the tiny remaining fraction of ETI's means those resources are not available to pursue other goals, such as for example figuring out what we are going to do when petroleum runs out.
We don't spend millions of dollars looking for perpetual motion machines, because we have experimental evidence and plenty of armchair philosophy to tell us that's likely to be a waste of time and money too. Of course we cannot absolutely prove perpetual motion is impossible; that would require examining every possibility for a perpetual motion machine. In practice, we tend to give up after the millionth failure.
ETI's already failed the Fermi Paradox, which rules out the vast possibility of ETI's which could potentially exist. It's as if we have already ripped the crime scene apart looking for evidence, and now we would have to spend lots of money going over the remainder once again. In the meantime, we have lots of other pressing problems which are more likely to admit solutions.
Other Comments by Teratornis
23. Comment #78724 by Teratornis on October 14, 2007 at 2:11 pm
In reply to comment #78713 by Rational_G
The energy costs of moving across the galaxy are much greater than most people imagine.
But not that great for sufficiently small robots. An expanding robot horde only needs to land a tiny (perhaps even microscopic) probe on a celestial body, which can then locate materials and energy to start replicating itself. Even if it landed with an insufficient supply of information on-board, it only has to know enough to build a receiving antenna to get the rest.
Since robots may be very long-"lived," they won't be in a huge hurry. It might take the robots a thousand years to reach the next star, but we would expect their speed to increase as they continue to learn.
Robots may also have lots of energy to spare, because they will be much tougher than fragile humans, who must expend vast amounts of energy just to remain comfortable as the weather changes. Shall we compute the mass of material we could send to the next star system with the energy humans currently expend just to remain comfortable? That alone is probably enough to propagate a robot horde that won't have to waste energy purely on life support.
Other Comments by Teratornis
24. Comment #78733 by Rational_G on October 14, 2007 at 3:44 pm
Teratornis:Actually, it's more like $66 million so far, not a billion, and all privately raised. Plus the facility will contribute to mainstream radio astronomy as well.
And as we all know, allocation of money is not a zero sum game. Searching for radio signals has little impact on solving our
energy needs. That is much more a matter of political will.
I can't agree with your conclusion that the odds are so small as to render the search quixotic.
Your assumption is that we have only a tiny window between the acquisition of radio technology and then being overrun by exponential expansion.
I'm not so sure that that's all there is to it.
Yes all life on earth expands to fill every niche. But even exponential expansion reaches a limit eventually.
Exponential expansion of intelligence on a galactic scale is something we can only speculate about.
It's an assumption (albeit a possible one) to insist on intelligent life exponentially overrunning the galaxy.
Plus species go extinct, also a tenet of natural selection, so who knows?
The jury is still out, and the comparison of this effort to a perpetual motion machine seems a little over the top.
This is a serious scientific hypothesis, which should not be discarded by Mr. Fermi's thought experiment.
And this scientific experiment can, and will, be carried out relatively cheaply while simultaneously contributing to radio astronomy.
We have barely begun to look, so I wouldn't say we had " a million failures".
Don't have to assume ETs are spending millions to send out powerful omnidirectional beacons. The SETI search assumes an ability to detect their own radio
transmissions. Plus they could also do targeted broadcasts, having detected earth like atmospheres in planetary systems, suggestive of life.
To quote Barney Oliver (one of the original SETI pioneers and former VP of Research & Development at Hewlett-Packard),
"To me, SETI is a search for proof that natural selection and evolution are ubiquitous and that they frequently lead to beings as
complicated as humans. We SETI buffs are enthralled by the knowledge that on this little planet the wonderful laws of physics,
have, in a few billion years, converted the ravening chaos of the Big Bang into the most delicate and complex of structures; into
spider webs and apple blossoms and leaping trout; and above all brains capable of modeling the exterior world and puzzling out
its origin. We want to know if this astonishing transformation is a local freak of nature or an inherent property of the Universe.
We very much suspect the latter."
And Frank Drake:
"Bracewell (robot) probes are an enormously expensive and grandiose enterprise. To succeed you have to send out (or replicate) millions of
probes, each which is a sophisticated spacecraft, that can travel fast, enter a planetary system, and put itself into orbit there. Then the
probes have to wait around for millions of years, functioning perfectly, while the home planet monitors them for updates."
It doesn't really pay to transport things through space as long as you can transport information at the speed of light.
Your microscopic self replicating continuously learning million year old perfectly functioning robot hordes? Well, maybe. and maybe not.
Maybe they're here already! But maybe we're still too primitive to be worth contacting, what with our constant warring and belief in supernatural beings!
You can come up with lots of scenarios. Instead of all this, we will just look and find out at relatively little expense. And still have lots of money left over
to find your oil substitute.
Cheers,
Rational_G
Other Comments by Rational_G
25. Comment #78738 by USA_Limey on October 14, 2007 at 4:30 pm
Do you not understand the implications of the Fermi Paradox?
Doesn't the zoo hypothesis give a respectable answer to the Fermi Paradox? I personally think human hubris and egocentrism are what gets in the way of many people acknowledging the possibility of advanced intelligent life elsewhere.
If we are going to be hard on the theists for thinking they are the object of a gods creation we must reject the Fermi paradox as a similar, (though obviosly not the same), kind of thinking.
Other Comments by USA_Limey
26. Comment #78769 by kev_s on October 14, 2007 at 8:06 pm
It will be just our luck if the first thing they pick up is another bl**ding tele-evangelist!Other Comments by kev_s
27. Comment #78770 by kev_s on October 14, 2007 at 8:18 pm
Wouldn't any society sufficiently advanced to build hordes of exponentially replicating robots think twice about doing that? I mean, sounds like they could get seriously out of hand and gobble up all resources available. However I could imagine a religious society might let them loose to spread "the word" about their religion. Perhaps the fact that earth is not crawling with these robots means that no religions like this have arisen elsewhere. That's a happy thought. .... Unless they were microscopic and act like a parasite on the human brain ... leading us to create more robots that will ... (Thinking of the parasitized ant climbing the blade of grass.) Oh dear, too much speculation.Other Comments by kev_s
28. Comment #78776 by steve99 on October 14, 2007 at 10:43 pm
I love these armchair philosophers here, who, by their briiliant analysis, have already decided that there is no intelligent life elsewhere in the galaxy. The only honest answer is that we simply do not know.
The honest answer is we don't know, but it certainly looks like there isn't. We see not the slightest sign of any harvesting of stars for energy, and every astronomical phenomenon we see can be purely explained by physics and chemistry. Not just our galaxy, but everything we see all the way back to the cosmic microwave background seems untouched. It really just does not seem feasible that possibly millions of civilizations could have arisen over billions of years and every one has been timid, stay-at-home and basically invisible.
And as for the 'zoo hypothesis', that does not work either, for the above reason - we see no evidence of either a keeper, or a cage!
Other Comments by steve99
29. Comment #78777 by Damien White on October 14, 2007 at 10:49 pm
The problem with extraterrestrial intelligence is that it could exist under any possible scenario or hypothesis. It cannot be limited. Therefore, attempts to anthropomorphise alien intelligence (to assign to it the motives and drivers of our own) are fundamentally flawed.It is OUR intelligence that dreams of spacefleets and battles and Death Stars. Maybe others don't.
Also, maybe the lack of contact with other intelligences is an indicator of the impossibility of interstellar travel.
Other Comments by Damien White
30. Comment #78780 by steve99 on October 14, 2007 at 11:15 pm
Therefore, attempts to anthropomorphise alien intelligence (to assign to it the motives and drivers of our own) are fundamentally flawed.
The only assumptions being made are that life requires energy, and replicates. That alone implies that extraterrestrial life should be visible.
Also, maybe the lack of contact with other intelligences is an indicator of the impossibility of interstellar travel.
Interstellar travel is not that hard. If our solar system were threatened we could build a colony ship using current technology.
Few people seem to realise how time overcomes space in the Fermi Paradox argument. All it would take is for a civilization to send out a couple of colony ships at far below light speed, and then those colonies, after they had arrived, to wait for a few millenia, and then each send out more ships, and the entire galaxy could still have been colonised many, many times over since its origin.
Other Comments by steve99
31. Comment #78788 by Teratornis on October 14, 2007 at 11:53 pm
In reply to comment #78770 by kev_s:
Wouldn't any society sufficiently advanced to build hordes of exponentially replicating robots think twice about doing that?
Societies as we know them do not "think" about anything. Only individuals think, and in our society, individuals are highly diverse.
If you went back to the 1700s and tried to explain the threat of unsolicited commercial e-mail to people back then, some might ask:
Wouldn't any society sufficiently advanced to create a SPAM problem think twice about doing that?
And the answer is clear: everybody you know hates SPAM, and yet we are overrun with it. That's because technology makes it so easy for anyone to send billions of SPAM e-mails. All it takes is a few people to create an enormous problem for everyone else.
I mean, sounds like they could get seriously out of hand and gobble up all resources available.
Well, duh. It's so hard to imagine them not getting out of control that their absence on Earth strongly suggests none have ever been built anywhere in our galaxy. And yes, such replicators would be chewing up all resources: every planet, every asteroid, eventually maybe every star. With their exponential growth they would quickly coat the surface of a celestial body and start chewing downward, converting its mass into more probes and shooting them out to eat up other celestial bodies.
Just as infectious bacteria eat or viruses hijack cells in a body and convert the proteins etc. into more bacteria or viruses.
However I could imagine a religious society might let them loose to spread "the word" about their religion.
Now you're talking. But it might not take a religion. We currently have a whole subculture of angry clever adolescent males (mostly males) who like to amuse themselves and earn bragging rights by writing virus programs and so on. Do you imagine those kinds of people will choose to act with restraint once it becomes possible to unleash a self-replicating doomsday bug?
Personally, I would not feel confident entrusting the future of civilization to the guys who are competing among themselves to fry all my computers. How about you?
Perhaps the fact that earth is not crawling with these robots means that no religions like this have arisen elsewhere. That's a happy thought. .... Unless they were microscopic and act like a parasite on the human brain ... leading us to create more robots that will ... (Thinking of the parasitized ant climbing the blade of grass.) Oh dear, too much speculation.
Well, one "solution" to the Fermi Paradox is that "they" already are here, but that just ends up violating Occam's Razor like any other theory about a vast yet undetectable conspiracy.
My favorite aspect of conspiracy theories is how the absence of evidence for a conspiracy is only further evidence of just how insidiously effective it is.
Of course God is the ultimate conspiracy theory too. To a theist, the fact that we cannot detect God is merely evidence of just how far beyond our mere human capabilities God is.
It may be worth considering that even ants have no difficulty detecting, say, humans in the vicinity. Even though we have overwhelmingly superior technology compared to ants, we would be hard-pressed to escape their notice. In fact our technology just makes us more noticeable.
Other Comments by Teratornis
32. Comment #78792 by Damien White on October 15, 2007 at 12:04 am
Steve 99:"The only assumptions being made are that life requires energy, and replicates. That alone implies that extraterrestrial life should be visible."
Granted, life requires energy, but how does it follow that it must be visible?
"Interstellar travel is not that hard."
I'm glad you know so much about interstellar space, a region that has never been entered or experienced by anyone from this planet.
Other Comments by Damien White
33. Comment #78794 by Teratornis on October 15, 2007 at 12:19 am
In reply to comment #78733 by Rational_G:
And Frank Drake:
"Bracewell (robot) probes are an enormously expensive and grandiose enterprise.
Sure, today. Just as in 1700, an iPod would have been an enormously expensive and grandiose enterprise.
Moore's law might eventually make Bracewell probes so cheap that we would be hard-pressed to prevent one from accidentally escaping. And it would only take one to slip out and get a foothold somewhere before extermination crews could get there, to set off the unstoppable exponential replication.
To succeed you have to send out (or replicate) millions of
probes, each which is a sophisticated spacecraft, that can travel fast, enter a planetary system, and put itself into orbit there. Then the
probes have to wait around for millions of years, functioning perfectly, while the home planet monitors them for updates."
I hope this quote is seriously out of context, because it makes Drake sound like yet another physicist who never read any biology. We don't need to build millions of self-replicators, we would only have to build one. That's the whole point of self-replication. You build the first one, and then it builds as many more copies of itself as it can find resources to build.
We already have self-replicating robots called "insects." They are not expensive - they are cheap. Actually they have a negative cost: you have to pay money to get rid of them, at least the pest species. They expand into any environment they can reach, because natural selection programmed them to do that.
If a Bracewell probe can be shrunk down to insect size, and it builds and replicates itself, then there's no "expense." The only expense is to build the first one.
Drake is thinking in terms of present-day technology, in which we need vast industries and hundreds of thousands of workers who use division of labor to solve the kinds of information-processing problems that a single cockroach manages to solve with its molecular machines all by itself.
The idea with a Bracewell probe is that it represents a technological society's having shrunk all the complexity of today's manufacturing enterprises down to atomic scale, so that everything it takes to build another Bracewell probe is in the Bracewell probe - all the necessary ability to manipulate matter, energy, and information.
Cockroaches can do it, so we know it can be done. It seems almost inevitable that human technology will get there, because we are always trying to shrink things to make them cheaper. Moore's law makes it seem likely that the miniaturized computing power will be there eventually. Nanotechnology may provide the matter and energy manipulating ability.
Humans might get to that level of technology in a century or two. Or maybe sooner. The vast age of the Universe means that if millions of other technological civilizations evolved before us, they've had plenty of time to get there first. We clearly see they haven't.
Other Comments by Teratornis
34. Comment #78798 by steve99 on October 15, 2007 at 12:50 am
Granted, life requires energy, but how does it follow that it must be visible?
The results of harvesting energy would be obvious. For example, Dyson Spheres would show up due to their high emission of infra-red, resulting from waste heat.
"Interstellar travel is not that hard."
I'm glad you know so much about interstellar space, a region that has never been entered or experienced by anyone from this planet.
Firstly, it is not that I know so much about interstellar space, it is that I read the writings of those who do. One of my favourites is the late Robert Forward - who came up with a combination laser/sail system that would do the trick. Also, have you heard of project Orion? It was a way to get to the stars using nuclear power (the 1963 test ban treaty ended the project).
Secondly, are you claiming that interstellar space is full of some hidden danger that we have not detected with all of our observations?
To me this sounds like a lot of wishful thinking: intelligent aliens must be out there, and interstellar must be too hard, which is why we haven't seen them... this does seem to be a common view, but I can't see any sense in it.
Other Comments by steve99
35. Comment #78808 by Teratornis on October 15, 2007 at 1:30 am
In reply to comment #78733 by Rational_G:
And as we all know, allocation of money is not a zero sum game. Searching for radio signals has little impact on solving our
energy needs. That is much more a matter of political will.
Advocates for every cause like to point to the small percentage of GDP their pet cause consumes.
This is not much different than the struggling dieter who concludes, quite rationally, that one extra doughnut isn't going to make much difference by itself.
But it's not going to be just one doughnut.
The other 99.9999% of GDP is not just sitting there up for grabs. Just about every resource is already allocated and has its vocal constituency. Which is to say there really is an opportunity cost for everything. We really are in a giant game of musical chairs. Weaning the industrial world off of petroleum is going to require a lot more than "political will." And in any case, what "political will" actually means is the willingness to say "No" to the endless parade of advocates and lobbyists each of whom points to the negligible resource percentage his or her pet cause requires.
I can't agree with your conclusion that the odds are so small as to render the search quixotic.
Then you might entertain the idea of a wager. Perhaps you and I could wager $100,000 on a First Contact within, say, 10 years. You bet for, and I will bet against. I'll give you 10:1 odds, meaning I will pay you $100,000 if First Contact occurs before the end of 2017, and you pay me only $10,000 if it does not. Does that sound like a wager you would make?
Obviously we would have to agree on there being indisputable evidence for First Contact which convinces the scientific community.
Your assumption is that we have only a tiny window between the acquisition of radio technology and then being overrun by exponential expansion.
I'm not so sure that that's all there is to it.
Well, obviously, if you believe there are millions of civilizations out there stuck in that window, for up to billions of years, then you must believe there is something more to it. Yet nobody has suggested even a remotely plausible hypothesis as to what that something more could be.
I'm going with Occam's Razor on this one. The simplest solution to Fermi's Paradox is that we are alone.
You have to believe that shortly after life invents technology, it must quickly and universally abandon the exponential growth which got it there. Which means that somehow, natural selection would stop operating on every member of a species (if only a tiny minority continued to exponentiate, they would quickly replace all the others who chose not to).
I could imagine that out of the millions of civilizations that the Drake equation predicts, there might be some which did abandon exponentiation at just the proper time. But all of them? What you're asking me to believe flies in the face of every available example of how life works.
Yes all life on earth expands to fill every niche. But even exponential expansion reaches a limit eventually.
Precisely. If any life had reached that limit, our view of the sky would be completely different than it is now. Assuming we even had a planet left to stand on.
Exponential expansion of intelligence on a galactic scale is something we can only speculate about.
Not exactly. We don't have to speculate at all to understand why the Fermi Paradox creates an enormous unresolved problem for SETI fans. Instead we have to speculate feverishly to come up with a way for ETIs to exist in spite of the Fermi Paradox.
And even in the absence of any credible way out of the Fermi Paradox, SETI fans believe it makes sense to listen for signals.
On the bright side, at least, Moore's law is reducing the cost of analyzing the data. Which means that in 20 years, the computing costs for SETI research will probably be at least a thousand times lower than they are today.
Thus if we care about the cost, it wouldn't hurt to delay the research. Even SETI optimists aren't predicting success soon (which is why I know you won't accept my generous wager). So what's the rush? Why not wait 20 years for the computing cost to go farther down?
In just 30 years, one personal computer could be as powerful as the entire SETI@Home network of today. (Assuming Moore's law holds up that long, with computers doubling in power every 18 months, which I believe works out to 20 doublings in 30 years, or roughly a million-fold increase in computing power. Nobody knows how long Moore's law will keep going, but so far everybody who has bet against it has lost.)
Plus species go extinct, also a tenet of natural selection, so who knows?
True, and extinct species are unlikely to be broadcasting radio signals for us to pick up. The fact of extinction is not cause for SETI optimism.
The window between powerful radio transmitters and self-replicating robots may be only a few centuries, so if every civilization goes extinct before getting to the self-replicating robot stage, it would be nearly miraculous if even one other civilization was in the window along with us.
You're talking about two randomly-located several-century windows overlapping in a time range of billions of years.
The jury is still out, and the comparison of this effort to a perpetual motion machine seems a little over the top.
I'll happily wager $100,000 against your $10,000 that the comparison will remain valid for the next ten years.
This is a serious scientific hypothesis, which should not be discarded by Mr. Fermi's thought experiment.
Fermi's thought experiment generates testable predictions which have thus far passed every observational test. Even if every technological civilization has failed to unleash robot replicators, where are the Dyson spheres? We should see at least some home stars emitting the characteristic spectra of waste heat rather than high-quality natural stellar radiation with its squandered potential to do useful work.
And this scientific experiment can, and will, be carried out relatively cheaply while simultaneously contributing to radio astronomy.
And what will radio astronomy contribute? Feynman said the whole field is unlikely to generate any practical result. So far he appears to be right. In any case, if the goal is promote radio astronomy, why not spend the money directly on radio astronomy? At least radio astronomers are sure that what they study actually exists.
The cost of SETI research will be much lower in 20 years, after Moore's law has pounded down computing costs by more than another factor of 1,000. Why not wait until then to listen for signals? What's the big rush?
Or we could wait a million years, by which time humans or our robot progeny will have overrun the Milky Way galaxy, with no need to spend a cent on SETI research directly. If anybody else is out there, we will bump into them in due course.
If humans are going to go extinct anyway, before we could get to the self-replicating robot stage (probably within a century or two), which would then let our robots eventually overrun the galaxy, then who cares if other civilizations exist?
Basically, I see only two options for us:
1. Either we go extinct very soon, or
2. Our descendants or our robots will overrun the galaxy and meet the neighbors (if any).
Under condition 1 it doesn't matter whether ETIs exist; under condition 2, we will inevitably discover any which exist in our galaxy, without having to make a special effort.
We have barely begun to look, so I wouldn't say we had " a million failures".
Astronomers have probably observed millions of stars with sufficient resolution to detect the characteristic spectra of Dyson spheres. I don't know the exact number. It might be possible to detect such spectra among billions of stars.
If intelligent life is common in the universe, then millions of technologically advanced civilizations have existed before us, yet none of them have built Dyson spheres we can detect, nor sent exponentiating robots to overrun our solar system.
Those are the millions of failures I'm talking about. The observational failures of SETI research thus far merely confirm what we can see already.
Other Comments by Teratornis
36. Comment #78838 by USA_Limey on October 15, 2007 at 3:54 am
I am going to admit I want there to be extraterrestrial intelligence despite the lack of evidence. Is this desire no different to the wish of the theist to believe in God?
I don't want to be guilty of theist thinking, but am not sure I can step outside of myself to consider this rationally.
Other Comments by USA_Limey
37. Comment #78886 by John Turner on October 15, 2007 at 8:59 am
Teratornis, Ive found your posts quite interesting and agreed with pretty much everything you've wrote. Nice oneOther Comments by John Turner
38. Comment #78925 by Pete_C on October 15, 2007 at 12:17 pm
This is a very interesting thread, with good arguments on both sides. I do tend to come down on the rare earth, or at least rare intelligence, side. But a few things about the robot horde scenario don't quite sit right with me.Let's say a probe is sent from the home planet to a star system with a known solid planet. The probe must be able to land on that planet and get to work. Now, occasionally, for whatever reason, that probe will not be able to succeed in building the next generation. So there's a probability, P, that the lineage continues, and 1-P that it will end right there. Depending on the distribution of P it is not entirely clear that a person sending out probes can sit back and be confident that their probes will overrun the galaxy.
Also, do the probes keep updated star charts, or can they detect planets and navigate to them? That's also something that can go wrong, isn't it? (Another reason for P to be made low)....and we can bet that the designer of the probes probably won't be around to get feedback and make improvements, right?
It just seems to me that the Fermi paradox has one weak point: the assumption that this self-replicating robot horde scenario is practically achievable. It may simply not be. We can't extrapolate from our earth experience of organisms spreading through all niches to the vastness of deep space.
We may very well be alone in the cosmos, but I'm not sure the Fermi paradox is rock-solid evidence for that.
Other Comments by Pete_C
39. Comment #78942 by Kakashi_monkey on October 15, 2007 at 1:37 pm
This is great, the E.T. search getting a big boost! Great to hear about a major development in a subject I think of as very important. I've known about the Allen Telescope Array since I read a book about it in 8th grade; someone in the book said, "We've been looking for the needle in the haystack with a teaspoon so far. The Allen Telescope Array will be more like a shovel." Go ATA!
Other Comments by Kakashi_monkey
40. Comment #78984 by Damien White on October 15, 2007 at 4:27 pm
Steve99,You're making the assumption that any alien civilisation will be building Dyson Spheres. There has been life on earth for a very long time and as far as I know, no-one has built a Dyson Sphere yet. Why do alien life forms have to follow your proposed model of civilisation expansion?
My point about interstallar space is that yes, we do not know what's out there. We don't even know how far the Oort Cloud extends. How long did it take us to discover the Van Allen belts? And any astronomer will tell you that there's rather a lot of mass still unaccounted for, somewhere out there. While I agree that the required propulsion methods are in theory quite simple, there are still enough unknown factors about the physical nature of interstellar space to make a blanket statement that 'interstellar travel is easy' quite absurd.
Other Comments by Damien White
41. Comment #78996 by roach on October 15, 2007 at 6:17 pm
USA_Limey,There is a difference between wanting something to be true and believing it to be so. Also, nothing turns on the belief that there are alien civilizations somewhere/time in the universe. Essentially no one organizes their lives around such a belief. If someone does, he will rightly be called crazy. No one is going to condemn you to hell, or say you're living in sin, or legislate morality and education because he/she thinks technologically intelligent aliens exist. It's a significant difference.
Other Comments by roach
42. Comment #79006 by Denevius on October 15, 2007 at 8:02 pm
Teratornis, those were some excellent points you raised. I'm neither a tech guy or a science guy, but if computers keep getting smaller, how do you know that an advanced civilization isn't using machines that we cannot detect, and that perhaps these machines have already swarmed our planet?I know how the atheist loves to compare humans to complicated machines, but if biology can be reduced in such a way, then you never know what is capable; or how an advanced civlization may manipulate and "program" tiny living organisms to perform certain tasks that aliens may deem important, but that we'd think are so bizarre that we simply aren't looking in that direction. Yet.
The SETI telescopes may be looking for the wrong signals altogether. But that definitely shouldn't mean that we give up our search for life beyond the Earth, if only for the fact that along the way we might discover something besides alien life that's really useful to us.
Other Comments by Denevius
43. Comment #79013 by dlitt on October 15, 2007 at 10:03 pm
I can hear the beep of an alien Sputnik. Other Comments by dlitt
44. Comment #79034 by Edanator on October 16, 2007 at 12:17 am
I've been critical of SETI for a long while. Not that I think it's impossible to discover extra-solar signals, it's just that the cost and effort may be too high, considering the minimal odds. I've also spent many hours in different forums explaining why Drake's equation is useless with our current data. By multiplying several unknowns you simply cannot get a useful value.However, I do think that we should pursue the search for extraterrestrial life both within and outside of our solar system. The present approach to discover extra-solar planets and focus on those, seems like a much better idea than randomly sweeping the sky for "intelligent signals". Any life detected, intelligent or not, would be one of the greatest discoveries in history.
Regarding the proponents for a lack of intelligent life in our vicinity, I think they are too sure of their ability to predict future technology, to understand alien thinking and how civilizations evolve and die. There are a lot of unknowns here as well, and it would be foolish to completely rule out extraterrestrial intelligence just because we do not understand how they could exist without us discovering them. (The argument from personal incredulity)
Other Comments by Edanator
45. Comment #79228 by Teratornis on October 16, 2007 at 2:26 pm
In reply to Comment #79034 by Edanator:
Regarding the proponents for a lack of intelligent life in our vicinity, I think they are too sure of their ability to predict future technology, to understand alien thinking and how civilizations evolve and die. There are a lot of unknowns here as well, and it would be foolish to completely rule out extraterrestrial intelligence just because we do not understand how they could exist without us discovering them. (The argument from personal incredulity)
And of course every SETI research program requires specific assumptions about alien thinking, namely, that extraterrestrial aliens will not construct Dyson spheres, they will not unleash interstellar exponentiating robots, but they will build super-powerful transmitters and aim them at Earth for eons.
Note that SETI optimists also argue from personal incredulity when they rule out Dyson spheres and exponentiating robots.
The question is whether we spend some serious money to look for transmitters, based on SETI optimists' personal incredulity, or spend the money on something else, based on SETI skeptics' personal incredulity.
Obviously, I like my brand of incredulity better, because it's more logically consistent. SETI optimists believe extraterrestrial civilizations will be just a little more advanced than our own (enough so they can afford to build big radio transmitters and keep them running for millions of years), but not a little more advanced from that, to the point of building Dyson spheres and exponentiating robots.
I think it makes more sense to interpret the absence of Dyson spheres and exponentiating robots as predicting the absence of big, powerful radio transmitters that keep running long enough for us to get around to detecting them.
Other Comments by Teratornis
46. Comment #79233 by Bonzai on October 16, 2007 at 2:36 pm
When super intelligent alien find us maybe we will behauled off to farms and be slaughtered for food, perhaps they will breed us in captivity with alien factory farming method too (so at least we will have plenty of sex). Better develop some technology to keep us invisible.
Other Comments by Bonzai
47. Comment #79235 by Teratornis on October 16, 2007 at 2:37 pm
In reply to comment #79006 by Denevius:
Teratornis, those were some excellent points you raised. I'm neither a tech guy or a science guy, but if computers keep getting smaller, how do you know that an advanced civilization isn't using machines that we cannot detect, and that perhaps these machines have already swarmed our planet?
Well, I don't know, but that would seem to imply that these alien machines use principles of physics we have not discovered yet, because we can detect machines as small as viruses already.
In any case, if aliens exist and we cannot detect them, then the current SETI research program is a waste of money.
The same goes for the Zoo hypothesis (the notion that super-advanced aliens have "quarantined" our solar system, giving us the opportunity to destroy ourselves or develop to the point where we qualify to join the galactic empire). If the Zoo hypothesis is true, then the current SETI research program is also a waste of money.
My comments in this thread are about whether the current SETI research program is a better way to spend money than on other open research questions. Such as what we plan to do when the petroleum runs out. I'd also mention the global warming problem, but more people are still in denial about that one than over the simple question of whether petroleum is going to run out. (There are some people who deny we are going to run out of petroleum, and they seem to be serious. Even if they are right, there's still the problem that we are transferring many billions of dollars into Islamic fundamentalism in exchange for the petroleum.)
If I were a Muslim, I'd be firmly convinced that so much of the world's petroleum underlies the holy lands of Islam as a direct result of Allah's plan.
Other Comments by Teratornis
48. Comment #79239 by bluebird on October 16, 2007 at 2:44 pm
when super intelligent alien find us...we will be hauled off to farms and slaughtered for food
"To Serve Man"
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This SETI website has more information (and a link to help financially for anyone interested):
http://www.seti.org/ata/
Other Comments by bluebird
49. Comment #79240 by Teratornis on October 16, 2007 at 2:47 pm
In reply to comment #78996 by roach:
There is a difference between wanting something to be true and believing it to be so.
No sane person spends millions of dollars looking for something unless they are pretty sure they will find it. For example, consider the salvage experts who comb the ocean looking for old sunken ships. They start with reliable information such as the ships' manifests, and the approximate locations where they sank. They might spend years and millions of dollars/pounds/euros, and find nothing, but no one doubts that the ships did sink and the cargo could still be on the bottom somewhere. (Currents could shift it around, and landslides might bury it, but the cargo is almost certainly down there somewhere.)
Therefore, a person who spends millions of dollars looking for radio transmissions from extraterrestrial civilizations must be driven by something akin to faith. It's at least enough faith to justify spending all that money.
How strongly do you need to believe something to spend millions of your own on it?
Also, nothing turns on the belief that there are alien civilizations somewhere/time in the universe. Essentially no one organizes their lives around such a belief. If someone does, he will rightly be called crazy.
Actually there are (or have been) space cults of this type. See for example:
http://en.wikipedia.org/wiki/Heaven%27s_Gate
The members of that cult committed mass suicide, so yes, they could rightly be called crazy.
Other Comments by Teratornis
50. Comment #79247 by Teratornis on October 16, 2007 at 2:57 pm
In reply to comment #78984 by Damien White:
You're making the assumption that any alien civilisation will be building Dyson Spheres.
SETI optimists believe no alien civilization has built Dyson spheres (in our light cone, at least, i.e., within the portion of the Universe that we can see), but millions of them have built powerful radio transmitters and some are aimed directly at Earth.
SETI optimists believe enough alien radio transmissions are reaching us right now to justify spending millions to search for them.
There has been life on earth for a very long time and as far as I know, no-one has built a Dyson Sphere yet.
Similarly, no one has built a powerful transmitter, aimed it at another star, and left it running for millions of years. But humans are reaching the stage where we could think about trying to do that (we can send short transmissions at other stars, although how long we could keep them running is an open question).
Why do alien life forms have to follow your proposed model of civilisation expansion?
Because that's what the SETI debate is currently about. It's about whether extraterrestrial aliens exist who are so similar to us that they do what we have thought about doing: build large radio transmitters and aim them at other stars.
Sure, there could be all sorts of other kinds of aliens in the Universe, but we cannot detect them with radio astronomy.
The only question to debate right now is, should we spend millions right now to comb the sky for artificial radio transmissions?
Note that the cost of analyzing the data will be much lower in the future, thanks to Moore's law. So waiting a few years can't hurt anything. The aliens have to be transmitting patiently for millions of years anyway to give us anything like a statistical chance of picking them up. It's very unlikely they will stop transmitting in the next 20 or 30 years.
Other Comments by Teratornis
Send a letter to the editor of the original media outlet.
letters@nytimes.com
1. Comment #78598 by foxfire on October 13, 2007 at 5:46 pm
Gee, that was when Newt Gingrich's "moral majority" effort took over Congress and the Whitehouse. I will not offer my opinion about how U.S. government support of things scientific have gone downhill ever since ;-)
And then there was SETI@home sponsored by UC Berkeley (I think, or maybe UCLA), where individuals were able to help "crunch" the data using their home computers (uploading/downloading data/results via the Internet).
The "Allen Array"...that's COOL!
Other Comments by foxfire