Forget SETI, this is how you find aliens: Hefty prof speaks
The truth is out there. Or maybe in here, actually
A top alien-hunting boffin has said that current efforts seeking extraterrestrial intelligent life are unlikely ever to work - not because there couldn't be any aliens out there, but because the methods themselves are wrong. He proposes several radical new means of finding out whether we really are alone in the universe.
Professor Paul Davies, physicist and cosmologist, is a Brit by origin but these days is chief of the "Beyond: Center for Fundamental Concepts in Science" outfit at Arizona State uni. He explains his thinking on the need to revamp alien-seeking methods in an article published yesterday by Blighty's Institute of Physics.
The main method used by humanity today to search for intelligent life elsewhere is the use of radio telescopes to scan the skies for RF-type signals, mainly as part of the American Search for Extra Terrestrial Intelligence (SETI) project.
In fifty years of looking, SETI has yielded very little of interest - though it did pick up a mysterious 72-second pulse, the so-called "Wow!"* signal, back in 1977. This has never been satisfactorily explained and has never recurred - on its own it doesn't really seem to mean anything.
According to Davies, the slender results delivered by SETI are very much to be expected. Even with the new Allen Telescope Array, gifted to the project by famed submarine-fancying billionaire Microsoft founder Paul Allen**, the prof doesn't expect radio sky-scan to produce anything much, even if the universe is crawling with aliens.
This is because radio signals which can be detected across interstellar distances aren't trivial to generate, and would mostly be directional. The old and excellent science fiction gag of TV broadcasts being picked up and avidly watched by aliens isn't realistic, fun though it is as a concept: the only real means open to humanity at present for sending interstellar messages is the use of powerful radar telescopes such as the famous Arecibo facility. (Or the Ukrainian job lately rented by Bebo in order to beam a blast of mindless web-2.0 babble at the possible hapless residents of the Gliese 581 system.)
Thus detectable radio signals would probably have to be purposeful interstellar signals, not merely incidental emissions naturally given off by any sufficiently advanced civilisation. According to Davies:
Unless the galaxy is teeming with civilizations frenetically swapping radio messages, it is exceedingly improbable that we would stumble upon a signal directed at another planet that simply passed our way by chance. A more realistic hope is that an alien civilization has built a powerful beacon to sweep the plane of the galaxy like a lighthouse. A beacon could serve a variety of purposes: as a monument to a long-vanished culture; as a way to attract attention and make first contact; as an artistic, cultural or religious symbol; or the cosmic equivalent of graffiti. It might even be a cry for help, or, as with the humble lighthouse, a warning.
"Shadow Biospheres" - the parallel-life ALIENS AMONG US
But even a superpowered radio lighthouse would need to stay operational for incalculable thousands or even billions of years to give us a decent chance of detecting it - Davies also raises the point that Sun-like stars, perhaps with attendant Earthlike worlds and civilisations, existed in the Milky Way well before our solar system even formed. There would be a major risk that any such beacon, even if built, was subsequently destroyed along with its parent civilisation and star - or was allowed to run down after its builders turned themselves into floating disembodied intelligences or whatever and forgot about it. By the time Mr Marconi got to work on newly-formed Earth, the fading pulses of long lost early-Galactic lighthouses would be lost far out in the vastness of intergalactic space.
So, what should we be doing instead of/alongside SETI?
According to Davies there are several rather more promising lines of enquiry which might help us get a handle on whether we are simply a bizarre statistical freak in a beautiful but cold and empty vastness, or in fact but one of countless civilisations scattered through time and space.
First up, there's the idea of looking into the likelihood of life developing given Earthlike conditions, which would help to put some actual numbers into the famous "Drake equation" postulated by the founder of SETI. If it is in fact reasonably likely for life to appear in liquid-water environments, Davies says, it might actually have happened several times right here on old Earth. Along with the microscopic life which eventually assembled itself into plants, animals and so forth, there might also be one or more "shadow biospheres" of microbes built along different chemical lines which have never started to organise themselves into bigger lifeforms.
Most terrestrial life is microbial, and biologists have only scratched the surface of the microbial realm. Many bizarre micro-organisms have been discovered, including the so-called extremophiles that thrive in conditions lethal to most known forms of life, but so far all of these organisms have turned out to belong to the same tree of life as you and me. However, this means little. Biologists customize their techniques to target standard life, so any microbes with a radically different form of biochemistry would tend to be overlooked.
In theory at least, the shadow-life might also be present here on Earth in larger forms - simply ones we haven't yet encountered. Various earthly environments haven't yet been much explored, for instance the deep oceans.
Then, there's the matter of intelligence. Even if the galaxy and universe beyond is hopping with biospheres containing life at various levels of organisation, it may still be that intelligence is so wildly unlikely as not to have arisen elsewhere - or indeed, it might be a counter-survival trait which tends to wipe its possessor out. Perhaps, every time intelligence arises, that species swiftly thereafter destroys itself by the use of planet-busting weaponry, or becomes enervated by spending all its time in immersive artificial game/entertainment environments and dies out because it can't be bothered to breed.
Magnetic monopole thieves may have left an IOU at the L4 point
However, if intelligence is not in fact an evolutionary dead end, we might look instead for the marks and signatures that super-advanced technology might leave. Rather then primitive radio signals, Davies thinks better results might be obtained by probing for the unique signatures of mighty astro-construction works such as "Dyson Spheres"***. Alternatively, near-future planet hunter telescopes and techniques might be used to probe alien atmospheres for industrial pollution of various kinds. Or, puissant ETs might be sniffed out by the neutrinos or gamma-rays belching from their advanced nuclear or antimatter powerplants.
Davies has pondered, too, on the so-called "Fermi Paradox", which suggests that if there are any interstellar-colonizing alien empires about they ought to have expanded through our solar system - or at least visited it - long ago. So where are they?
The professor points out that they may well have been and gone millions of years ago, perhaps mining our solar system bare of some valuable resource we don't even know about (naturally, as the thieving aliens have nicked it all) and departing while our remote microbial ancestors were still thinking about assembling themselves into primeval slime.
Davies thinks it's plausible, though, that the ancient visitors may very well have left behind a message, monument or probe of some kind. This would not be on Earth's surface, of course, as the smart aliens would know that would lead to it being destroyed or buried by the constant churning or the planetary crust as seen over these terrifically long timescales.
Rather, says the prof, it would make more sense to look for such a thing on the Moon or at the gravitationally-stable L4 and L5 points, where a spacecraft needs to expend no power to hold position. Beaming an active-SETI radio message at these positions, speculates the prof, might awaken some aeons-dormant machine left behind by the aliens who snaffled all our magnetic monopoles, which would then automatically hook up to the internet and brief us on the galactic scene.
If that's not enough to be going on with, Professor Davies has more - messages written in our own or other organisms' genetic code, "post-biological" aliens who have abandoned their flimsy flesh bodies to live as augmented computer intelligences in superconducting quantum computers (situated in intergalactic space to benefit from the cold there, naturally) etc etc.
Much of it is laid out in the IOP article here. Alternatively there's more detail in the prof's latest book, The Eerie Silence: Are We Alone in the Universe?, available this month from Penguin. ®
*So named for the notation made on the margin of the "Big Ear" telescope's data printout by the discovering boffin, Jerry Ehman.
**WARNING: IT angle.
***In which a powerful civilisation might enclose its sun in a colossal sphere, so creating unbelievably huge amounts of useable land area compared to measly little planets.