Experimental cosmologists using photonics to search Andromeda for signs of alien life

"Are we alone in the universe?" The question has fascinated, tantalized and even disconcerted humans for as long as we can remember.

So far, it would seem that intelligent extraterrestrial life—at least as fits our narrow definition of it—is nowhere to be found. Theories and assumptions abound as to why we have neither made contact with nor seen evidence of advanced extraterrestrial civilizations despite decades-long efforts to make our presence known and to communicate with them.

Meanwhile, a steady stream ofdiscoveriesare demonstrating the presence of Earth analogues—planets that, like our own, exist at a "Goldilocks zone" distance from their own respective stars, in which conditions are "just right" for liquid water (and thus life) to exist. Perhaps even more mind-blowing is the idea that there are, on average, as many planets as there are stars.

"That is, I think, one of the amazing discoveries of the last century or so—that planets are common," said Philip Lubin, an experimentalcosmologistand professor of physics at UC Santa Barbara. Given that, and the assumption that planets provide the conditions for life, the question for Lubin's group has become: Are we looking hard enough for these extraterrestrials?

That is the driver behind the Trillion Planet Survey, a project of Lubin's student researchers. The ambitious experiment, run almost entirely by students, uses a suite of telescopes near and far aimed at the nearby galaxy of Andromeda as well as other galaxies including our own, a "pipeline" of software to process images and a little bit of game theory.

"First and foremost, we are assuming there is a civilization out there of similar or higher class than ours trying to broadcast their presence using an optical beam, perhaps of the 'directed energy' arrayed-type currently being developed here on Earth," said lead researcher Andrew Stewart, who is a student at Emory University and a member of Lubin's group. "Second, we assume the transmission wavelength of this beam to be one that we can detect. Lastly, we assume that this beacon has been left on long enough for the light to be detected by us. If these requirements are met and the extraterrestrial intelligence's beam power and diameter are consistent with an Earth-type civilization class, our system will detect this signal."