Space odyssey continues - on computers
Interview: Dr Duncan Forgan (University of St Andrews) …
Space odyssey continues - on computers
Dr Duncan Forgan is a Postdoctoral Research Fellow in the School of Physics and Astronomy at the University of St Andrews. He describes himself as “either an astrophysicist, an astrobiologist or a scientist in search of extraterrestrial intelligence (SETI), depending on who asks the question,” but the focus of his research is the use of numerical simulation to understand star and planet formation, as well as atmospheric models of unusual planetary systems and theoretical calculations of how alien civilisations might evolve and become detectable. He also works on problems related to the emerging field of astrobiology – the study of life in the Universe – which brings together academics from across the physical sciences, including astronomy, physics, chemistry, geology and biology.
Life has never been the same again for Duncan Forgan since he set his eyes on Arthur C. Clark's famous science fiction novel 2001: A Space Odyssey. And 20 years later, he is still on a similar quest – using simulation rather than a spaceship in his search for intelligent extraterrestrial life.
“We all go through our dinosaur phase,” he explains, “and I was always interested in space.” His passion for space exploration was also ignited by an inspirational teacher at secondary school, who made him think hard about physics and encouraged him to go to university in Edinburgh to study astrophysics, then become a Postdoctoral Research Fellow at the Institute for Astronomy, also in Edinburgh.
Now based in St Andrews, Forgan came to international media attention in 2009, when he published a paper describing a new algorithm which he had developed to work out the possibility of finding intelligent life forms in space – and suddenly found himself under attack from his colleagues as well as an overnight media star.
The story began after Forgan attended a lecture on SETI (the search for extraterrestrial intelligence) during his first year as a PhD student. Although SETI was outside the scope of his PhD Thesis, Forgan told his supervisor that he had an idea for a project – to create an algorithm for a new simulation which would also improve Drake's Equation, an argument to estimate the probable number of extraterrestrial civilisations in the Milky Way.
Forgan says the first step in the process is to estimate the simple possibility of life, then the possibility of intelligent life, then the chances of a civilisation which would wish to communicate with other life forms and, finally, a civilisation which has already sent out a signal. In addition, you have to take into account many factors such as habitability, as well as key milestones a planet must pass to survive long enough for animals to evolve and develop complex brains, then go on to develop technological tools.
One problem with Drake's Equation, says Forgan, was that you could “stack it to suit your own theories” however you liked. “It may be useless in predicting intelligent life, but it tells you what the problem is,” he also explains. “My improvement was to take what we were learning about extra solar planets, and conduct simulations based on that data, rather than having to squeeze all that data into some very simple terms in Drake's equation.” But according to Forgan himself, even this new simulation was not good enough to work out the possible existence of alien life. “It was an elegant approach to the problem, but there are simply too many parameters,” Forgan continues. “Key factors also change as life evolves – it is not just a question of where to find life forms, but when.”
Other complications are the biological side effects of civilisations emerging and what are called “false positives;” for example, basic theories may suggest you need a constant store of oxygen for life to survive, but there may be alternative ways to replenish supplies. “You can’t reduce it to a single equation,” says Forgan, “but you can reduce it to a single algorithm, much the same as those employed in war games.”
His simulation may not have provided all the answers, but it was a useful tool for building galaxies – and also hit the headlines as soon as the paper was published and found by the press. Forgan thought his paper was “a way of explaining how complex the problem is,” but the media focused on a few simple numbers which suggested that he really could predict the probability of alien life. And if the media were right, he says, it must be an extremely busy galaxy, according to the numbers they reported.
In his simulation, Forgan suggested three different scenarios: one which took a generous approach to probability, one very strict scenario and one which assumed there were lots of “just habitable” planets; but a “cosmic storm” erupted when several other scientists accused him of making unscientific predictions, without even reading his original paper. “It was a baptism of fire,” says Forgan, describing his appearances on TV and his arguments with colleagues.
In Forgan’s view, the process helped to “quantify our ignorance, and how bad we are at finding the answers,” but the episode was also useful media experience and opened up a few doors in the world of research. He plans to run the simulation over again in the very near future, incorporating lots of new information, including data from the latest Kepler mission, but next time he will exercise more caution. Since reviewing his earlier project, Forgan also questions how we start the search for alien life. For example, do we use radio or optical telescopes? Do we focus our attention on a small patch of sky or study the whole sky at once, looking for very small changes? “Or do we stare out at the universe and look for something weird?” he asks. “All we need to know is what to look for,” he adds, “and how to study the data.”
As part of the search for intelligent life, Forgan also wonders how we would be able to detect dead civilisations, in the knowledge that our own planet now has the power to destroy itself. And if we did detect the signs of “suicidal” civilisations, perhaps we could then learn from their mistakes, he suggests.
The search for intelligent extraterrestrial life will always be philosophically intriguing and stimulate progress in science, particularly in computation, but it also encourages many young people to think about science as a future career. Astronomy in general is another “golden weapon” for public engagement in science, and a major driver of technology – for example, charge-coupled devices in smartphones were first developed for astronomy.
SETI is not Forgan’s only passion, however. In his “day job,” he explores the “local Universe” – how stars and planets form from clouds of dust and gas, and how they die, and what makes planets suitable for life. Part of this involves studying brown dwarfs, substellar objects not big enough to sustain fusion reactions in their cores, unlike stars such as our own Sun. Another of his favourite topics is protoplanetary discs – frisbees of matter which form around stars at the same time that solar systems are born, then go on to form planets. According to Forgan, “we must unlock their secrets if we are to understand the solar systems we see in our galaxy.” His work sets out to help us understand how planets are born in these discs, and how they grow, move and interact with each other to produce the rich variety of planetary systems seen in the galaxy today, as well as the newly discovered “free-floating” rogue planets which wander around without stars.
Although his Master’s project focused on the use of data analysis in astrophysics, studying “how the behaviour of super-massive black holes in the centres of galaxies is connected to their neighbours and the surrounding environment,” Forgan knew from early on in his academic career that he wanted to do theoretical work. “As a theorist, the whole thinking process is different,” he explains. “Instead of working with the data you observe to test a theory, you start off with a theory of your own and generate the data that observers might see.” He is also keen to stress the contribution of astronomy and physics to science in general and to our sense of perspective. “The more we learn about how the Universe works,” he explains, “the more it puts us human beings in context.”
Forgan's career path has taken him to interesting and “unexplained” places in physics and astronomy, as well as astrobiology, but his core work remains simulation, and this is where his research will continue to focus. Nowadays, he may not be spending much time on the search for intelligent life, but he returns to the subject again and again, not just because it's interesting but also inspiring. So what does he really believe?
“When it comes to whether or not there’s intelligent extraterrestrial life, I’m a pessimist,” Forgan replies. “But what I believe doesn’t matter, because it's still worth doing the experiment. We have the resources and techniques for finding weird things out there, and are also collecting the data. Why not check before we give up? After all, we haven’t failed yet.”