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The
Search for Extra-Terrestrial Intelligence (SETI) |
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SETI: Is It Worth It?
It's a risky long shot that burns up money and might never, ever pay off. So is searching for intelligent creatures on unseen worlds worth the candle? After all, aren't there better ways to use our monies and technical talents than trying to find something that's only posited to exist: sentient beings in the dark depths of space? This is a question that surfaces more often than dead fish. "Why should my precious dollars be used for SETI when there's so much suffering in the world?" It deserves an answer. By Seth Shostak Senior Astronomer, SETI 08 November 2007 To begin with, allow me to get a technical misunderstanding off the table. As many readers know, SETI is not paid for with your tax dollars. At least, not if you're in the United States (where most SETI is conducted). Since 1993, when Congress killed the NASA SETI program, the search for signals from other societies has been funded by private donations. To be candid, even before that date, the amount of tax that was SETI-bound was only about three cents per year per citizen. But let's not argue whether that was a heavy burden or not: the facts are, it's currently zero. If you don't want to contribute to SETI, then it costs you nothing. That small truth hardly silences critics, however. They look at SETI donors, and wonder aloud why these folks don't write those checks for medical research, foreign aid, or other humanitarian programs. In other words, the critics' plea is that we put all our money where our collective mouths are. Well, such a circumstance has never been the case, and never should be. A cursory glance at history shows that, even when people are routinely dying of hunger in the streets, some fraction of any civilized nation's resources have gone to seeking new things, or creating new things. Donors and patrons will always spend some monies on activities that, when analyzed on the crassest, basest level is "useless for society." They do that for lots of reasons – burnishing their image, love of Bulgarian ballet, or maybe just a desire to save fresh-water otters. But that's beside the point: if you give money to the local heart association, maybe it's because you're thoroughly altruistic. Or perhaps, deep down, you figure it might help you or your family in the long run. Either way, it's a good thing from society's standpoint. Yes, but isn't "good" relative? Shouldn't there be a cost-benefit calculation here? Shouldn't philanthropists opt for the most effective project, in terms of societal improvement? That may sound good, but even aside from issues of free will, that argument leads to a terminally murky battle on what's important and what isn't. And sometimes what's unimportant today can become very important tomorrow. Consider some examples. In Italy at the start of the 17th century, Medici family members Ferdinand and Cosimo proffered a regular allowance to an ambitious academic from Padua, Galileo Galilei. The guy found spots on the Sun and moons around Jupiter. You could have bought some meals with that money instead. But Galileo's work turned our worldview upside down by showing that Copernicus was right. I'm glad he got the florins. Two hundred years later, Emperor Joseph II of Austria ponied up some coins to fund Wolfgang Mozart. Was this a good idea? Mozart was just writing music, for goodness sake. You can't eat music (unless you're a goat). But I can feast on it, and I do. Then there are SETI's analogs from the first years of the twentieth century: the multiple attempts to pierce the heart of Antarctica and reach the South Pole. The principal men who led these forays into the lethal landscape at the bottom of the world – Shackleton, Scott, and Amundsen – did so for approximately the same reasons that motivate anyone with ambition: career advancement, glory, adventure, or simply to prove that they had the right stuff in the white stuff. But we're not talking about their motivation: we're asking why anyone would fund these guys. All three had donations from individuals. James Caird, a wealthy Dundee jute manufacturer, gave Shackleton a hefty hunk of change; steel magnate William Beardmore funded Scott on his first expedition; and Lincoln Ellsworth, son of an American industrialist, wrote checks for Amundsen. There's hardly any mystery about why these private citizens would send explorers to realms that offered only frostbite and a bit of national pride in return. Yes, they were in it for the image building – the celebrity that would rub off on them if their boys brought back the bacon (only Beardmore seems to have expected to make a profit.) But these sponsors, like their proteges, were also driven by curiosity – an inherent interest in exploration, in learning about the unknown. They wanted to know what was out there. For these folks – people who couldn't breach the frontiers themselves – it was exploration by proxy. So, and perhaps too obviously, it's not inevitably about financial return. But it's also not always about new cures, new products, or even the alleviation of suffering. As Richard Feynman once said about physics, "it's like sex. Sure, it may give some practical results. But that's not why we do it." And really, I think the same is true of the quest to find a signal from the stars. Funders of SETI are not putting their boodle on the table for commercial or national advantage. They're not hoping we'll be able to proselytize the aliens, nor do they await an opportunity to beat their chests with satisfaction if we find them. And while there's always the possibility that we'll learn wonderful things from an interstellar transmission, SETI speaks to a quintessential human need even without that carrot – the quest to know. More to the point: to know how we fit in. What is our part in the enormous cultural tapestry that we suspect threads the star fields of the Galaxy? Are we truly biologically or intellectually special? One radio whistle from the cosmos would answer that question. Even if a discovery deflates our egos, it's still something that would be incredibly interesting to know. Ignorance is not bliss – it's only ignorance. When Copernicus argued that our view of an Earth-centered universe was parochial and wrong, he cracked a door in a stuffy house. SETI could blow out every window in the place. As technologist Paul Allen said while commissioning the first elements of the new telescope that bears his name, "I like to call SETI the longest of long shots. But if this array picks up a signal, that would be an amazing thing – a civilization-changing event." Surely, that's worth the candle. |
The
'Rare Earth' Delusion
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Come out, come out, wherever you are You never write, you never call ... Tim Radford on the puzzle of the absent alien: inspiration for art and astronomers and soon to star in a Science Museum exhibition Tim Radford Thursday August 25, 2005 Guardian ET became a star without ever turning up for an audition. Alien life is the ultimate paradox: everybody knows what an alien looks like but no one has ever seen one. The universal neighbourhood could be crawling with citizens but none ever popped round to say hi. The extraterrestrial has spawned good books, mediocre art and bad movies; provoked serious speculation and a new science called astrobiology; and triggered a 400-year religious and philosophical debate, all without putting in a single appearance. If life exists on Earth - a nondescript planet orbiting an undistinguished star in a neither-here-nor-there galaxy in an ordinary corner of the universe - then it ought to exist on at least some other planets around a proportion of other suns in at least a selection of other galaxies. There are at least 200bn galaxies, and each may be home to 200bn stars. Even if the evolution of a sentient, intelligent, technologically aware civilisation is rare, the firmament should still be fizzing with life. But, as the physicist Enrico Fermi once asked, in a question now known as Fermi's paradox: "Where is everybody?" The alien is one of two possible answers to life's great question: is all this just for us? But if the alien exists, then alien civilisations would have begun to ask themselves the same question perhaps a billion years ago. The heavens should be ringing with long-distance calls, the galaxy buzzing with randomly directed robot probes. Forget about UFOs, Area 51 and the Men in Black: nobody so far has tried to get in touch. That hasn't stopped humans hoping for a call from Alpha Centauri or Andromeda Central. A new exhibition - it will open in October - in preparation at the Science Museum in London will underscore just how ardent that hope has been. Contemporary humans have populated the heavens with Little Green Men and Ming the Merciless, Mr Spock, the Klingons and the Borg, Daleks and Monsters from Mars, the Pod People and the Thing from Outer Space but wistful wondering about other worlds began a long time ago: before Copernicus, Galileo and others had firmly established that Earth was a planet, just like Venus or Mars. Epicurus wrote to Herodotus in 300BC proposing there could be "infinite worlds both like and unlike this world of ours" inhabited by "living creatures and plants and other things we see in this world". Kepler thought it highly probable that Jupiter was inhabited and Christian Wolff in the 18th century even worked out what a Jovian might look like. If bodily size was proportional to the eye, and the square of the diameter of the pupil was inversely proportional to the intensity of available light, and if Jupiter was 26/5 times further from the sun it would get 5/26 times the available light so, bingo, a Jovian would need to be 1,400ft tall. The astronomers Herschel and Bode proposed that even the sun might be inhabited, Benjamin Franklin wondered about the constitutions of the people who lived on Mercury, so close to the sun; and a Scottish clergyman called Thomas Dick in 1828 calculated there might be 2.4bn inhabited worlds within the visible universe. In 1837, he went further. He reasoned that the population density of England at 280 souls per square mile meant 53 billion lived on Venus and more than 8 trillion people might dwell on the rings of Saturn. Puzzlingly, until 1898, when HG Wells wrote The War of the Worlds and supposed an invasion of technologically superior, malevolent Martians, human attitudes to citizens of other planets were mostly benign. Emily Bick, curator in South Kensington and one architect of the exhibition on the science and psychology of aliens, reckons that Europeans began to project their fears of the unknown on aliens at about the time they completed their exploration of the globe. There were unearthly phenomena in ancient texts - Ezekiel's chariot, perhaps, in the Bible - but in general, until the 20th century the Earth itself might conceal sufficient objects of fear. Who needed alien abduction, rectal probes and sperm theft when witches directed your love affairs and fairies stole male babies to fortify fading fairy virility; when the dead could rise from the grave as vampires and siphon off a nightly supply of blood? Who needed the invaders from outer space in the television series V, when monstrous reptiles routinely stalked the night? "Think about things like Beowulf: Grendel, and Grendel's mother and the dragon were all sort of reptilian and scary and gross; just swampy monsters, cold-blooded, evil, not human, not of a mammalian line," she says. "Before, it was maybe the forest, or strange things that happened in the sky, or weird things that happened in a fairy world. Now we have dismissed all that with rationality, so what's left? Aliens are the one thing we don't know about, so we can project all these same fears, these same stories, onto this new world." She is a serious science-fiction fan and the exhibition will divide aliens into a number of categories, each of which explores some serious aspect of science or culture. Steven Spielberg's ET, for instance, illustrates the concept of neotony: look like a baby and people will fuss about you. "ET has the proportions of a five-year-old child, he has a huge trunk and huge, huge eyes that probably wouldn't even fit in his skull if they were like human eyes: they would be too large. He acts as a child's playmate, they dress him up in doll's clothes like one of their toys." There are aliens cute and cuddly, aliens hyperintelligent, aliens sinister, aliens from Roswell and Area 51 and of course, the aliens from Hell. Fear is a big part of the extraterrestrial story. One cornerstone of the show will be the Hans Geiger creature from Alien, the monster that impregnated John Hurt, terrorised Sigourney Weaver and nearly got the spaceship's cat. "She embodies all of the separate kinds of fears we have about aliens. She is both reptilian and takes over bodies, possesses us and has this monstrous feminine aspect. We have things that can transform and shape shift, we have the Thing. The problem with the Thing - that we are afraid of - is that the Thing is able to take over human bodies and we don't know what we can trust," Bick says. "Most of the alien films of the 1950s are allegories of the cold war; things like Invasion Of The Bodysnatchers - it's the 'reds under the beds' fear: your neighbours are replaced by aliens." She is keen on the theme of aliens as tricksters who invade by appearing to be like humans. "I Married A Monster From Outer Space is an interesting example: it's a pod people sort of thing. A woman marries a man who turns out to be a monster from outer space, surprisingly enough, and most of the men in the village turn out to be monsters and the way they find out is that they are not able to reproduce. Their wives don't get pregnant. It is an allegory on closeted gay men, in its own way. They save the day by going to the maternity ward, because all the men there with their wives are obviously red-blooded humans, so they go and rout the aliens and everyone is happy." Aliens often appear as humans, and not just because it saves a bomb on special effects. Aliens are often like us, and they speak English too. Captain Kirk tended to find beautiful women with beehive hairdos on every farflung planet, but Star Trek was an excuse, using stories as allegory, to explore problems here on Earth. The point is, she says, it's easier to identify with aliens who look like us. You can't really have an alien love story with someone who looks like a giant beetle. The exhibition will explore robot aliens, emissaries from hypercorporate states, cod-Gnostic struggles to discover true reality (think of the Matrix) and aliens with teeth. "There seems to be a primal fear of aliens with large teeth, aliens that are kind of reptilian. We have the Dracula thing. The Predator is stylised to look sort of reptilian and he has four sets of teeth." It will open with aliens imagined by humans because that's the only data we have. It will explore some of the scientific substance behind all the science fiction conjecture. It will consider the Drake equation, the famous calculation that plays with the probabilities of habitable planets around stars not too different from the sun, and comes up with an indeterminate but awesome number of possible worlds just in one galaxy. It will contemplate the carbon basis and the universal pressures of natural selection that naturally lead to convergent evolution, in which similar environments tend to produce similar designs even though the starting points might be vastly different. It will look at biological universals likely to pop up on planet Tharg, such as bilateral symmetry. "We have two hands, two legs, two hemispheres of the brain," says Bick. "Most animals on Earth have bilateral symmetry. There are reasons for this. You have a spare of everything, which is quite useful. You can balance yourself, you have a lot of good things going on. So there is speculation that these structures would replicate themselves with aliens and so there is a possibility that aliens on other planets might be like terrestrials, given terrestrial conditions. We don't know for sure." We don't know for sure because aliens continue not to visit. One in 100 Americans may believe they have been abducted (cue for a short lecture on sleep paralysis, which manifests itself in pressure on the chest and the experience of being taken away) but if the laws of physics extend beyond Alpha Centauri, then they have not. The distances to the nearest stars are awesome, and the energy costs literally astronomical. There has been a brisk debate about why ET never phoned the Seti Institute, and why signals from Earth might never get through to Cygnus X-1 or a planet in the Pleiades. One - and some serious planetary scientists and astronomers back this theory - is that we really could be alone: that life itself is rare and intelligent life probably confined to one planet. Not so, say others: the raw materials for life as we know it are being manufactured by exploding stars and carried by icy comets all over the solar system and - since the Copernican principle says there is nothing special about the Earth - by extension, everywhere. Which brings us back to Fermi. Where is everyone? Life must be common, even if communities are light years apart. That could be all it takes to keep the neighbours from getting the message or putting a call through, say engineers such as Christopher Rose of Rutgers State University, New Jersey, in the journal Nature, and biologists such as Clive Trotman at the University of Otago in New Zealand, who did a similar set of sums in his book The Feathered Onion last year. You can't just broadcast a message saying, "Is anybody out there?" The signal dissipates as the square of the distance. By the time you get to Pluto, it's already vanishingly faint. So you send an ultra-powerful signal as a focused laser beam. How much energy would that take? How long could you afford to transmit? How many directions must you point the transmitter to cover the whole sky? (The answer to that one is 100,000 trillion). And what chance a citizen of an alien civilisation is tuned in when your one-second message whistles by at the speed of light? The arithmetic, says Trotman, predicts one-way communication with both antennae pointing at each other will happen for one second every 10 billion billion years. Assuming, that is, both civilisations are using the same wavelength. Don't wait up for ET. Use your imagination instead. |
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Types cast Seth Shostak's guide to fictional aliens Seth Shostak Thursday August 25, 2005 Guardian Alien This vicious creature, with more teeth than a bandsaw, would never survive in the galactic gene pool. Its eggs sit around on worthless planets, hoping a passing spaceship will land and investigate. The eggs explode in any intruder's face, implanting an alien embryo. After a hasty gestation, the creature arranges its own caesarean delivery, bursting from the host's chest. This is similar to the repulsive reproductive cycle of the ichneumon wasp. Imagine if making human babies required a biologically compatible visitor from another world. It's far more efficient to find a partner for reproduction at the pub. Alien's scheme is going to have a very low yield. Daleks Americans like anthropomorphic aliens; the British prefer Daleks, who resemble oversized salt shakers with smallpox. These aggressive creatures, the mutated remnants of a nuclear war on their home planet, roll around in tank-like epidermises. But if they're advanced enough to manage interstellar contact, why can't they do some genetic engineering and unburden themselves of those debilitating mutations? Their metal mantles seem unsuited to locomotion on anything rougher than a studio floor. Imagine Daleks at the beach. Fitting an extra motor and a dust bag would at least make it useful for vacuuming the living room. ET ET and his buddies journey here to augment their collection of plants, a field trip that sounds plausible until you note they come from the Andromeda galaxy - a tedious 2m light years away. Are the hundred billion planets of their own galaxy cursed with uninteresting flora? Unintentionally abandoned, ET chills out with some latchkey kids from suburbia, appropriate given that he is a kid himself: big eyes, short nose, and a small, cuddly body. Improbably, his biochemistry is so similar to ours, he gets drunk on supermarket beer. This isn't an alien - it's every child's dream of the perfect pet. Roswell aliens Some folks think that in 1947 alien rocket jockeys made a last-minute navigation error and crashed in the desert. The putative victims are generally portrayed as humanoid, if somewhat shorter than us, and with bigger heads - like children. While not impossible, this is unlikely. The fact that we have two eyes is good engineering, but having four appendages is an evolutionary accident. Most Earthlings have six (they're called insects). The Roswell aliens resemble us because we relate better to anthropomorphic creatures. Real aliens won't be so similar. They probably won't crash, either. The Man from Mars by Frank R Paul (1939) This Red Planet resident and comic book cover art, a cross between a 7ft-high bat and Pinocchio, was a valiant attempt to design a realistic alien. Mars gravity is only 38% of Earth's, ergo this Martian's imposing stature. Barrel-size lungs suck in the Red Planet's thin air. Sadly, these adaptations are inadequate. The landscape of Mars is dry as dust, cold as Antarctica, desperately short of oxygen, and stung by lethal ultraviolet light. If we ever meet real Martians, we'll need a microscope to see them, and a drilling rig to find them. The Red Planet's surface is surely as sterile as a mule. Tribbles These pesky aliens from Star Trek do only one thing: make more Tribbles. How this happens is discreetly obscure, as are all anatomical features of these furry lumps. But modesty aside, reproduction - whatever the dirty, nasty mechanics - eventually relies on food to bulk up the offspring. What is it that Tribbles eat? Air? Without legs, and too large to float, the Tribbles seemed destined to stay in one place and mound up. Given their fleecy physique, it's possible that such creatures are bred by enterprising extraterrestrials for the garment trade. Seth Shostak is senior astronomer at the Seti Institute, California |
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| The E.T. Equation, Recalculated
By Frank Drake Wired Magazine Dec 2004 Fifty years ago, those of us who dreamed about finding extraterrestrials thought we knew where to look: planets with temperatures somewhere between the freezing and boiling points of water. Given warm little ponds, simple chemical reactions would produce life, and evolution might eventually produce intelligent creatures. While working at the National Radio Astronomy Observatory in the 1950s, I tried to estimate the number of planets in our galaxy with intelligent, technological civilizations. The result has come to be called the Drake equation (not by me, although it sure is nice). But I've recently realized that the numbers we've been plugging in are too small. We placed undue limitation on the kind of stars that could support life, which restricted the variable R*. We underestimated the number of possible life-sustaining planets because we thought they had to be confined to a particular orbit: within the continuously habitable zone, or CHZ. But our math said that our own sun's CHZ was so narrow that Earth was barely in it. Life, especially complex life, would be very rare; ne would be very small too. What did we miss? Venus. It's not much closer to the sun than Earth is, but the temperature there reaches 900 degrees Fahrenheit. Every square inch of the surface radiates about 17 times as much energy as it gets from the sun. Blame the greenhouse effect; Venus' thick carbon dioxide atmosphere contains that energy. So, theoretically, a planet could be far from a star and still have life, if the atmosphere was thick enough to keep it warm. These "goldilocks" worlds, not too hot or too cold, greatly enlarge the CHZ - Jupiter's moon Europa, enveloped not by CO2 but by ice, may be an example. Planets might not even need stars. No one has directly observed a rogue planet, but we know they're out there; astronomers have discovered more than 130 extrasolar planets, and their orbital motion tells us that during the formation of a solar system, extra planets get dumped into the star or kicked out of the system. The castaways wander in the great empty spaces between the stars, the orphans of the Milky Way. In theory, if the rogue's crust contained radioactive elements, their decay could keep the surface warm enough for life. Eighty percent of the stars in our galaxy are small, faint red dwarfs, what astronomers call M stars. They'd draw a planet so close that tidal interactions would hold one face toward the star, the way the moon faces Earth. At the center of the dayside, temperatures would range from warm to broiling. On the nightside, the air itself would be frozen into snowflakes - unless, as we think might be possible, powerful winds blew from the dayside. Somewhere between twilight and noon would be what I call a Camelot zone. It'll have good weather all the time and a warm breeze, like a never-ending balmy evening. We used to think N was about 10,000. Now I think it could be a great deal larger. To find out, we must point our radio telescopes at new targets. We have to look between stars - there could be friendly rogues calling from the gossamer swath of the Milky Way. There might be planets nestled near cold, tiny stars, where intelligent creatures would have no concept of day or night. And I wonder, do these Camelotians ever sleep? Frank Drake originated the idea of listening for life on other worlds with radio telescopes. He is senior director of the Center for the Study of Life in the Universe at the SETI Institute in Mountain View, California. |
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