Good news: Aliens aren’t currently taking over the universe.
That’s according to Brendan Mullan, Carnegie Science Center’s resident astrophysics expert and Buhl Planetarium Director. He and a group of scientists created the Glimpsing Heat from Alien Technologies Survey, or G-HAT, which attempted to locate extraterrestrial life in 100,000 galaxies.
“An extraterrestrial civilization, if they’re really advanced and they use a lot of energy to do whatever it is extraterrestrial civilizations do — we don’t even know — they would have to use a lot of energy and get rid of it as waste heat,” Mullan said. “And basically we’re looking for a lot of waste heat in other galaxies.”
He compared it to using a laptop for a long time — the more energy the computer uses, the hotter it becomes underneath.
The team used NASA’s WISE orbiting observatory to see if they could detect radiation in the galaxies.
“It scanned around, looked all over the sky, and developed a catalogue of things that shine brightly in infrared radiation, and that includes stuff in our galaxy — starts, nebula, all that, and it includes a ton of other galaxies,” Mullan said.
The researchers used that catalogue to determine that there’s either no extraterrestrial life, or if there is, they aren’t using a lot of energy. Mullan said there is the slight possibility that they could be using a different kind of energy source, but any energy that is recognizable on earth must reradiate somehow, making it unlikely that the infrared wouldn’t detect it.
Mullan said these findings weren’t particularly surprising to him.
“I’ve always kind of thought that if there were these extremely advanced civilizations that took over the entire galaxy, or just about, and used all those stars to power whatever it is they want to do I thought that it would be pretty obvious and we would have discovered that by now,” Mullan said.
However, he said the study sheds some light on Earth’s energy consumption.
“We’re basically defined by our voracious appetite for energy,” Mullan said. “We use more and more of it all the time and our energy needs have doubled in the past 30 years, and if you extrapolate from there, you’ll find that we need to use the equivalent of a whole star’s worth of energy in just a couple hundred years.”
Mullan said the fact that they were unable to find extraterrestrial life using stars as energy sources actually made him feel uneasy.
“The fact that we haven’t seen anyone try or succeed out there is a little frightening to me. It means it can’t be done, or it shouldn’t be done, or nobody’s tried,” Mullan said. “There’s something missing that I find a little bit disturbing.”