If alien life exists in our galaxy, it must be trying to interact with us. The probability of interaction could be greatest at the moment.
Research efforts dedicated to discovering and developing new methods to communicate across cosmic distances may ultimately offer greater chances of making contact.
What is the best way to find intelligent alien life?
This is the grand challenge for astronomers engaged in the Search for Extraterrestrial Intelligence (SETI).
In a new study, Jodrell Bank astrophysicist, Dr. Eamonn Kerins, proposes a new strategy based on game theory that could tip the odds of finding them more in our favor.
Dr. Kerins said, “In game theory, there is 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 civilization out there trying to find us, are playing exactly this kind of game. So, if both they and we 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 civilizations there have similar evidence about our planet, both sides should be strongly incentivized to engage in SETI towards each other because both will be aware that the evidence is mutual.”
The idea is being dubbed as “Mutual Detectability.” It states that the best places to look for signals are planets from which we would be capable of determining that Earth itself may be inhabited.
The study proposed the idea of examining transiting planets. Transiting planets make up most of the planets.
Dr. Kerins said, “What if these planets are located in line with the plane of the Earth’s orbit? They’ll be able to see Earth transit the Sun, and they’ll be able to access the same kind of information about us. Our planets will be mutually detectable.”
The Earth Transit Zone is a special region of the sky from which an extraterrestrial observer would detect Earth by seeing its transit in front of the Sun. According to scientists, there are multiple potentially habitable planets located in this zone.
But the question remains whether to listen out for a signal from them or send a signal to them. Dr. Kerins’ work shows how this paradox can be resolved.
Dr. Kerins said, “It turns out that civilizations 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 civilization with 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.”
The study suggests that most of the habitable planets in the Earth Transit Zone must be in orbits around low-mass stars that are dimmer than the Sun. Dr. Kerins shows that these civilizations would have a clearer view of us.
Using the Mutual Detectability theory suggests that targeted SETI programs should concentrate on looking for signals from potentially habitable planets around dim stars.
Dr. Kerins said, “Soon, we should have the first catalog of planets that may be inhabited by civilizations who already know something about our World. They may know just enough to be tempted to send a message. These are the worlds we need to focus on. If they know about game theory, they’ll expect us to be listening.”
- Eamonn Kerins et al. Mutual Detectability: A Targeted SETI Strategy That Avoids the SETI Paradox. DOI: 10.3847/1538-3881/abcc5f