Researchers at the University of Manchester, UK, suggest that ‘game theory’ could help scientists discover intelligent alien life.
A new paper published in The Astronomical Journal by Jodrell Bank astrophysicist, Dr Eamonn Kerins, proposes a new strategy based on game theory could help scientists locate intelligent alien life.
The Search for Extraterrestrial Intelligence (SETI) programmes tend to use one of two approaches. One is to conduct a survey that sweeps large areas of sky in the hope of seeing a signal from somewhere. This survey approach can quickly generate huge volumes of data that can be very hard to search through comprehensively.
An alternative approach is more targeted, where the search focuses more intensively on specific star systems where life might exist. Kerins explains: “In game theory there are a class of games known as coordination games involving two players who have to cooperate to win but who cannot communicate with each other. When we engage in SETI we, and any civilisation out there trying to find us, are playing exactly this kind of game. So, if both we and they want to make contact, both of us can look to game theory to develop the best strategy.
“If we have evidence of a potentially inhabited planet, and civilisations there have similar evidence about our planet, both sides should be strongly incentivised to engage in SETI towards each other because both will be aware that the evidence is mutual.”
The new theory suggests examining transiting planets, planets that are on orbits that pass directly across the face of their host star, briefly making it appear dimmer. This dimming effect has been previously used to discover planets and transiting planets make up most of the planets we currently know about.
Should we wait for signals from other planets?
The question remains whether to listen out for a signal from them or to send a signal to them. Some scientists, like the late Professor Stephen Hawking, have warned of potential dangers in sending signals to civilisations that could have vast technological superiority over us. Others have noted that if every civilisation has the same fear then there will be no signal for anyone to detect, the so-called SETI Paradox. Dr Kerins’ work shows how this paradox can be resolved.
“It turns out that civilisations on a planet located in the Earth Transit Zone can know whether the basic evidence of their transiting planet is clearer to us or if our signal is clearer to them. We’ll know this too. It makes sense that the civilisation that has the clearest view of the other’s planet will be most tempted to send a signal. The other party will know this and so should observe and listen for a signal.”
In the research paper Kerins shows that the vast majority of habitable planets in the Earth Transit Zone are expected to be in orbits around low-mass stars that are dimmer than the Sun. He shows that these civilisations would have a clearer view of us. The Mutual Detectability theory suggests that targeted SETI programmes should therefore concentrate on looking for signals from potentially habitable planets around dim stars.
