Astronomers are on the hunt for signs of alien civilizations in space by searching for things like extraterrestrial solar panels or planetary atmospheres spewing pollutants.
The team, from the Harvard-Smithsonian Center for Astrophysics and the University of Rochester in the US, believe these so-called “technosignatures” are evidence of intelligence in other places than Earth. If advanced life forms exist they'll be using electronics, the thinking goes, and that means emissions that could be detected.
"Technosignatures relate to signatures of advanced alien technologies similar to, or perhaps more sophisticated than what we possess," Avi Loeb, chairman of Harvard University’s Department of Astronomy, said this month. "Such signatures might include industrial pollution of atmospheres, city lights, photovoltaic cells, megastructures, or swarms of satellites."
Loeb told us his team will be awarded a total of $286,926 by NASA over two years to scour space for technosignatures. They will kickstart their search by trying to find signs that civilizations are trying to harvest star light for energy with the use of solar panels.
The researchers pointed to the example of Proxima b, the closest Earth-like planet that may be habitable located some 4.25 light years away. Proxima b is believed to be rocky and is tidally locked to its parent star Proxima. That means that the same side of the planet faces the small yellow star as it orbits, and the other side is permanently shrouded in darkness.
"If a civilization wants to illuminate or warm up the night side, they would place photovoltaic cells on the day side and transfer the electric power gained to the night side," said Adam Frank, a professor of physics and astronomy at the University of Rochester working on the study.
"Our job is to say, 'this wavelength band' is where you would see sunlight reflected off solar panels. This way astronomers observing a distant exoplanet will know where and what to look for if they’re searching for technosignatures."
“Solar panels absorb light up to a certain wavelength and reflect the rest,” Loeb explained to The Register. “This leads to a spectral edge in their reflected light, which is distinguishable from the ‘red spectral edge’ produced by vegetation. By observing the starlight reflected off the surface of a planet, you can tell whether it is coated with solar panels.”
Their search will be narrowed down to exoplanets that are more likely to have environments that can support and sustain life. These candidates orbit their stars at distances that keep its surface temperatures warm enough to hold liquid water, are rocky, and have atmospheres filled with gas.
“The search for extraterrestrial intelligence (SETI) has always faced the challenge of figuring out where to look. Which stars do you point your telescope at and look for signals. Now we know where to look. We have thousands of exoplanets including planets in the habitable zone where life can form. The game has changed," Frank concluded.
Click here to meet your nearest alien neighbour now!
In other related news across the pond, a pair of astrophysicists from the University of Nottingham in the UK reckon there are more than 30 intelligent species of alien living in the Milky Way.
“There should be at least a few dozen active civilizations in our Galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth,” said Christopher Conselice, who led the study published in The Astrophysical Journal this week. “The idea is looking at evolution, but on a cosmic scale.”
Venerable astroboffin Frank Drake came up with his famous Equation in 1961, guestimating how common intelligent life might be. It's controversial, and has been reviewed since, but math ain't everything.
Well, if there are extraterrestrials that have managed to invent the internet and are now reading El Reg in another planet far away, we welcome our alien overlords. ®