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Humans have used some really high-tech equipment — radio telescopes, interferometers — to search for other beings that may live in the cosmos, but have still found nothing. Could it be that our idea of aliens is getting in the way?
Because Earthlings are the ones seeking out life-forms from other planets, there are going to be Earth-based biases that could be making aliens invisible to us even if they are desperately trying to communicate somehow. We’re always looking for planets with conditions similar to those that life flourishes in here. SETI (search for extraterrestrial intelligence) initiatives like Breakthrough Listen also tend to use AI to hunt through data for potential signs of technosignatures. The problem is that these points of view are way too human.
"If E.T. was looking at us, what would they see?" MIT grad student and researcher Claire Webb said at the recent 235th meeting of the American Astronomical Society (AAS) in Honolulu. She had a point.
If all life on Earth (we haven’t even gotten to the rest of the universe yet) needs sunlight, water and oxygen, then how do you explain extremophiles like nematodes or tardigrades? How can creatures exist that creep around in the searing heat of a geyser or the total darkness at the bottom of the ocean? How do you explain single-celled organisms that can reproduce asexually by splitting themselves? What about things that can stay dormant for hundreds of years? And the bizarre Shewanella microbe, which eats nothing but electricity?
Breakthrough Listen is trying to find life on other planets with AI, but the catch here is that AI can’t do anything without being trained by humans. That means whoever creates that artificial intelligence is going to program it with a human idea of how aliens might be trying to reach out to us, and they do that without even thinking about it. We might assume aliens use radio telescopes to reach out to us because we use radio telescopes in many of our efforts to catch alien signals.
This assumption is biased towards our species and held back by our technological limitations. Echoing Carl Sagan, we are currently going through tech puberty right now, but a civilization far out there could be light-years ahead of us.
Then you have NASA spacecraft like TESS hunting for planets whose habitability is determined by what defines livable conditions on Earth, like light, heat, and what we consider breathable air. At a press conference during that AAS meeting, NASA’s Gabrielle Engelmann-Suissa presented a slideshow on what TESS is looking for when searching for alien planets that could possibly be hotbeds of life.
“How cloudy could the atmosphere be? How hot could the surface be? Livable temperatures? How much water vapor will be in the atmosphere? What observable signals could we detect from this planet?” were just some of the questions she asked, adding that modeling newly discovered planets could “motivate technological advances needed to detect [habitability] signals”.
What Engelmann-Suissa suggested is by no means the wrong approach. We need an arsenal of everything we know about life, even if it is limited to just one planet, if we’re going to go out there scouting aliens. We just have to think beyond the pale blue dot and consider the possibilities of creatures that can survive in impossibly hot or freezing temperatures, or swimming in strange waters, like the methane and ethane seas of Titan, that would be toxic to anything used to breathing in the oxygen from H2O underwater.
Then again, maybe humans are onto something with the type of signal detection systems we’ve designed to receive a message from E.T. Sometimes using what you know can be an effective approach.
“Not only do radio telescope surveys search wide areas of the sky [for alien signals]; they might even be good at it,” said James Davenport, a research scientist from the University of Washington’s Department of Astronomy, at the same AAS meeting.
We’ll just have to wait and see...or listen.