Seth Shostak, SETI mouthpiece and fellow Bay Area-er, is at it again in the astronomy community, contributing an article to Space.com entitled, “When Does SETI Throw in the Towel?” Now, Dr. Shostak. SETI can throw in the towel right now.
Before I go into the arguments, let me refer readers to the excellent Extraterrestrial intelligent beings do not exist, by Dr. Frank Tipler. It was quite a few years ago when I looked up to the stars, with Dr. Tipler’s book in my hand, that I realized he was right - the stars are empty, ready to be harvested and spun into pure energy with the help of gravitational singularity goodness. No aliens, green bug-eyed ones or otherwise, are waiting there to be inconvenienced.
The meat of the argument is that all intelligent civilizations will inevitably develop von Neumann, self-replicating probes, and send them out in all directions. When your economy grows to a certain level (like the level ours will be in 50 years if we survive), a von Neumann probe costs no more than a candy bar. Based on the age of the universe and our galaxy in particular, we shouldn’t be able to get up in the night and go to the bathroom without stubbing our toe on an alien artifact.
Now to go into Shostak’s article:
“At what point would you abandon the search?”
Answer: never. Believers will never abandon the search. If the aliens aren’t swallowing stars right in front of our face, they must be broadcasting on the electromagnetic spectrum. If they aren’t broadcasting on the electromagnetic spectrum, they must be sending each other neutrino bursts. If they aren’t sending neutrino bursts, they must be somehow manipulating the fabric of spacetime itself to covertly send messages. Like theists, they’re willing to bend over backwards to get the assumptions they need to give their belief any chance of success.
I personally think the fiction of the mid-20th century is to blame. When these scientists were kids, aliens were all over the telly, and they were inspired, and they’re not going to jettison that inspiration now. Today, there are still aliens on TV, but Interweb killed the alien star, and the primary demographic who buys into UFO cults are of a certain age range, what can be described as middle-aged. Not to say that people of this age are somehow dumber than the new generation, just that their cultural background has more aliens in it, so there’s a slightly greater propensity to believe, one that is fading.
Could it be that those of us who still hope to tune in other worlds may be missing some writing on the wall? Some dead-obvious, chiseled text with a simple, if disappointing message: “There are no aliens”?
The question seems fair, since SETI’s obvious analogs–the historical voyages of discovery made in the centuries following the Renaissance–were completed in considerably less time than SETI has been beating the cosmic bushes. Columbus spent five weeks finding North America (and he wasn’t even looking). Captain Cook, a true paragon of explorers, and a man who mapped places that Europeans didn’t even know were places, never mounted an expedition that lasted more than three years.
But those analogs are false. The South Pacific, for all its watery wastes, is comprehensible in size. Even Cook’s unimpressive Whitby collier, powered by sailcloth, could cross the Pacific in a matter of months, come about, and cross again in a different direction. His quarry, the islands peppering the ocean like coins scattered onto a living room carpet, signaled their presence by clots of clouds even when the islands themselves were below the horizon.
The SETI wilderness is incomparably larger, obviously, and its quarry is cryptic. Even if there are ten thousand transmitting societies nestled in the arms of the Milky Way, we might need to search millions of star systems before we find one. The actual number of star systems that radio SETI experiments have carefully examined is fewer than a thousand.
This bit is what inspired me to write this post. The SETI advocates are starting to give indications that we’ll actually need to go to the stars to find the aliens. Centuari Dreams points out an article on Rasmus Bjørk in The Guardian that exemplifies the trend in this direction, “So much space, so little time: why aliens haven’t found us yet”. The relevant part:
He found that even if the alien ships could hurtle through space at a tenth of the speed of light, or 30,000km a second, - Nasa’s current Cassini mission to Saturn is plodding along at 32km a second - it would take 10bn years, roughly half the age of the universe, to explore just 4% of the galaxy. His study is reported in New Scientist today. Like humans, alien civilisations could shorten the time to find extra-terrestrials by picking up television and radio broadcasts that might leak from colonised planets. “Even then, unless they can develop an exotic form of transport that gets them across the galaxy in two weeks it’s still going to take millions of years to find us,” said Mr Bjork. “There are so many stars in the galaxy that probably life could exist elsewhere, but will we ever get in contact with them? Not in our lifetime,” he added.
Postulations of ships moving at only 1/10c are moot, because we can easily envision ship designs that send payloads at near-c using no more than a ton or so of antimatter. Not to mention Bjork ignored the possibility of self-replicating probes, but based his calculations on actual civilizations being founded at each star.
Our galaxy is 100,00 light years across - that’s it. Our universe is more than 10 billion years old, and the basic building blocks for life have been around nearly Our that long. If the assumptions of the alienites are even vaguely correct, our galaxy should have been colonized and EM-soaked thousands, if not millions of times by now. Centauri Dreams brings up one obvious error in Bjork’s arguments:
An obvious objection is that self-replicating probes could do the job much more efficiently and in far less time (Frank Tipler has done interesting work on this question, arriving at times in the millions of years to explore the entire galactic disk). But Bjørk points out the problems with such probes. They might easily move beyond control of the humans who designed them, with fatal consequences. So he bases his study on non-replicating devices, reaching this possible answer to the Fermi Paradox: “We have not yet been contacted by any extraterrestrial civilizations simple because they have not yet had the time to find us. Searching the Galaxy for life is a painstakingly slow process.”
Because self-replicators might move beyond control of the people that design them, all intelligent civilizations across the universe will freeze development on them, forever? I don’t think so. Even if such self-replicators do hose their parent civilizations, they should still be out there, ready to optimize us into paperclips, or fonsweebs, or whatever it is they do. Shostak again:
And frankly, it’s conceivable that SETI’s basic assumptions might be proven wrong. Imagine that the new space-based telescopes (COROT and Kepler) currently being deployed to hunt for Earth-size planets around other stars come up empty. That would be a premium-grade bummer. But even if (as widely expected) they do discover rocky worlds, it’s possible that a decade or so down the line, their telescopic successors–atmosphere-sniffing instruments such as the Terrestrial Planet Finder–might fail to find any extrasolar worlds on which life has taken hold.
Indeed, I was hoping the article would mention so-called hypertelescopes, and it did. Last year I wrote a quickie on the topic for Wisegeek.com. Hypertelescopes are distributed telescopes that combine data from arrays to perform aperture synthesis - basically, faking a ginormous telescope. Instead of building a lens 1000 km across, you float a thousand stations within a 1000 km area, and cross-reference their data. Using this technology, we will be able to get km, and then subkilometer resolution of planets 10 light years away or more. Brian Wang has more on this.
Luckily, hypertelescopes may finally put the nail in the coffin of SETI - perhaps 100 years from now. We will be able to see even the simplest of flora, if they exist in large numbers on exoplanets. (Though what we should really be looking for are Dyson spheres or disappearing stars, and as far as we can tell, there are absolutely none.) After we look at a good thousand earth-sized objects and see nothing there but vast, dead wastes, we’ll start getting used to the idea that we are truly, actually alone.
For the lamest excuses of all, there is always Digg:
For intelligent life in our galaxy alone, the chances are at least one in a 100 billion because we exist(philosophers need not reply), There could be many civillizations out there that are billions of years old, and probably communicate by some other means.
Their technology could be so advanced that it is spiritual, supernatural and magical.
(imagine what can become of this technology us humans have today)
We’re probably being protected by them by galactic law( a.k.a Spiritual Law)hint hint.
Hint hint! Your supernatural fantasies have no place in scientific discourse! Hint hint! Another:
A blanket statement that “There are no Aliens” is rather retarded.
There are a LOT of assumptions being made:
-The aliens are more advanced than us
-Aliens have faster than light communications
-The aliens are listening at all
-Maybe they are replying we just don’t have the technology to detected and decode it.
-Maybe they are there and they don’t want anything to do with us.
Then of course you have things like:
-The universe is roughly 12 billion years old, earth is 4.5 billion; That’s lot of time to transcend.
-There are no black holes intercepting signals
-They are in the same galaxy.
There is a LOT of space out there. Billions upon billions of stars. To think 1 small planet in 1 galaxy is the only one to produce life is statistically ridiculous.
This reply combines all the assumptions that people use to justify their alien desires. The assumption that some aliens are more advanced than us is correct. FTL communications is not necessary to send signals out. We have statistical tests that could easily distinguish intelligent signals from background noise, no matter how different their culture is. Whether they’re listening or not, they’ll send out tons of noise. The Prime Directive is stupid.
As another poster points out, because the sample set of life is 1, the standard deviation is infinite, so there is no reason for us to think that the vastness of the cosmos implies anything about the probability of life. It’s that intuitive feeling of the universe being big that causes people to think that there must somehow be aliens. But that bigness is merely big to us. The configuration space is so much larger, and indeed, most atomic configurations are not realized in this universe. People’s intuition is as if there is some cosmic arbiter that says, “okay, it’s been 100 billion planets, time to seed this one with life now!” Why at 100 billion? Why not seed life on every 10^10^123 planets, instead of merely every 10^11? The multiverse is infinite. There can be an infinite number of intelligent civilizations, each living alone in their own universe. To think that the vastness of space implies the presence of aliens is itself statistically ridiculous.
See my other post on this topic:
Aliens - There Are None.
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