Many physicists like to throw the word “universe” around: Secrets of the universe. Mysteries of the universe. Origin of the universe. Even parallel universes.
It is a big subject. Fully befitting, we like to think, our big brains.
Sure, you might make more money than we do. You might drive fancier cars and have a bigger house. But we study the universe: top that.
But look a bit closer and the physicist’s universe tends to be a fairly arid place, riddled with abstract notions of guiding principles and fundamental constants. Spend enough time with a physicist, in fact, and it’s easy to forget that the universe actually has stuff inside it.
Jill Tarter, though, hasn’t forgotten.
She has the requisite credentials, of course: a PhD in Astronomy from Berkeley and a long and distinguished research career capped by the usual dollop of academic accolades. But Jill has spent the majority of her professional life driving forward the science and technology of the Search for Extraterrestrial Intelligence – SETI for short – rigorously scanning the sky for the signs of some signal sent to us from outer space.
Outer space? Well, not that outer, actually, when you get right down to it.
Right now, SETI is focusing its telescopes on our nearest neighbours: those stars “only” a few hundred light years away. Or, to put it another way, those within a mere one percent of the 75,000 lightyear distance across our Milky Way Galaxy. Let’s not even mention the other 100 billion galaxies out there, each containing roughly 100 billion suns.
These sorts of numbers quickly produce the sort of intellectual vertigo that astronomy is famous for. With all those mind-boggling possibilities set among all that “real estate”, as Tarter calls it, you might even wonder if it makes a difference where we point our telescopes at all.
But it does. Quite a bit, actually. With the launch of the Kepler spacecraft in 2009, the new field of hunting exoplanets – planets orbiting suns other than our own – exploded. Astronomers have now located over 2700 exoplanets and, as Tarter told me, the tide has now turned sufficiently that most scientists would say, “Yeah, there are probably more planets than stars out there”.
And it is precisely towards these newly-found exoplanets that SETI is now directing its telescopes. Not only because we know there are planets there. But also because they are relatively close by. Relatively, of course, is the operative word. Any communication with a civilization that is several hundred light years away would be problematic, to put it mildly, requiring upwards of half a millennium to exchange a simple greeting. Assuming, of course, there is anybody there to speak with anyhow. Finding a planet – even a planet potentially habitable for life as we know it – is one thing. Discovering, let alone chatting with, a distant civilization is something else again.
So is it hopeless?
Tarter, unsurprisingly, is undeterred. Potential contact may be of all sorts of different forms, and alien civilizations might well be thousands, or even millions, of years ahead of us technologically. There is, we’re reasonably confident, the limiting fact that no signals can go faster than light. But beyond that, nothing is certain. We just don’t know. Which is why we have to look carefully at any signals anyone may have sent us.
“SETI Founder Phil Morrison always had these wonderful things to say. And one of them was, ‘In any science, where the error bars are in the exponent so you don’t know whether the number is 103 or 108 , that’s not a theoretical science. That’s an observational science.’”
A reasonable claim. Yet many are still skeptical. In fact, a good number of people I’ve met in the scientific community are not exactly what you’d call SETI sympathizers.
Some of this, of course, is the age-old story of academics eating their own: any funding which is directed to some other area of inquiry is seen as money which is taken out of their own desperately needy hands.
But it’s hard not to sense something stronger at play. However much SETI people might talk about the finer details of signal processing algorithms and possible technological spin-offs, all this talk of alien transmissions and extraterrestrials is all a bit … déclassé for a good many academics.
Not to mention politicians, always on the lookout for tangible and personally painless ways to publicly demonstrate that they are going to “clean up Washington” and “eliminate waste”.
Tarter, of course, has seen this movie many times before.
“People say, ‘Well, if you’ve looked for fifty years and you haven’t found anything, there must be nothing out there’. They just haven’t got much of a concept about how vast the cosmos is, how large this cosmic haystack that we’re trying to search is and how many different dimensions – all of these different ways that signals could be generated that we haven’t yet searched for.”
And even those who might otherwise be sympathetic in principle are increasingly concluding that a long-term, multi-general search is inherently unsustainable in our world of ever-collapsing timelines and mounting short-termism.
So, ever the pragmatic problem solver, SETI’s full-time Fundraiser-in-Chief now has her eyes set on a different sort of funding mechanism.
“I think, ultimately what SETI needs is an endowment. This kind of project, which might be multigenerational, doesn’t do well with the annual funding cycles. We were a NASA project for a while. It didn’t fit with the congressional cycles. It was too easy a target for ‘Little green men. Ha, ha, ha’. And there you go: no more SETI funding.
“We need to be cognizant of the fact that when we’ve built observatories in the past, we have often failed to fund the scientific research there. You fund the instrument, but you don’t fund the scientific research. Here, we need to fund the instrument, but we also need to provide funding for the smart, young people who are going to do the next big thing with the instrument: think of the next new signal processing capability, bring in the next new technology, make it all happen.”
Of course, not all the arguments against doing SETI research are driven by political grandstanding or scientific snobbery.
A rather more serious argument against the likelihood of sharing the galaxy with others is the one first put forward by the famous Italian physicist Enrico Fermi that still bears his name. The Fermi Paradox states that any alien civilization that had achieved sufficient technological expertise and lasted sufficiently long would have moved out from its own star system and eventually colonized the galaxy; and the fact that they’re not here means that we have to be the first.
Like any serious scientist, Tarter meets the criticism head on.
“Well, it’s important to deal with that because paradoxes can be extraordinarily strong. But I think that the problem with that argument is being able to say, ‘They’re not here’. And again, forgetting entirely about popular stories of alien abductions and all that silliness, the truth is that, actually, we can’t say that.
“We’ve so poorly explored our own local backyard in the Solar System we can’t say that there is no evidence of an extraterrestrial craft or markers or the Obelisk from 2001. And we also have this bias that space colonization is going to be big wet biology boldly going forth. Maybe that’s not how it happens. Maybe it’s small, really intelligent little nano-probes. Maybe they don’t have to send their biology, they send the information, they recreate what they want to at their destination. We haven’t seen any evidence for any of that, but it could be here. The best that we’ve been able to do is say, well, if they’re in the Lagrange points of the Sun and the Earth system, those places where there’s a lot of gravitational stability, you don’t have to extend a lot of energy to stay in one place, to station keep. We’ve looked at some of those with reflected light and with radar and, yeah, we probably would have seen a Battlestar Galactica kind of thing, but not a small probe. So in fact, we can’t make that very definitive, ‘they’re not here’ statement.
“And there are other explanations: the entire galaxy may be colonized, but that does not mean that every star within the galaxy is colonized; there are diffusion solutions to this problem that leave pockets unexplored. So I don’t know. It’s not something to be sneered at, but I also think that the last sentence of the founding 1959 Nature paper by Cocconi and Morrison is kind of the right approach to this.
“They said, ‘The probability of success is difficult to estimate, but if we never search the chance of success is zero’.
“So we’re searching. We may be wrong. We may be looking in the wrong way. We may not have yet looked in the right direction, with enough sensitivity. It may be something else entirely, but we are trying to use the tools of the 21st century that we have to see what is.”
A good philosophy. It is, after all, what science is supposed to be all about.
For a complete list of Ideas Roadshow videos featuring Jill Tarter, click here. The eBook called SETI: Astronomy as a Contact Sport containing the unabridged Ideas Roadshow conversation with Jill and a range of additional resources is available on Amazon while the podcast of the one-hour conversation will be available on iTunes later this week.
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