What SETI will look for over the next 20 to 200 years for life, may be totally unlike anything we are now doing.

How scientists are expanding the spectrum for SETI and the search for alien life

BERKELEY, Calif. - Twenty years after the movie "Contact" brought the search for extraterrestrial intelligence, or SETI, to the big screen, it's dawning on astronomers that the real-world plotline might turn out to be totally different 20 years from now. So far, SETI has been dominated by radio telescope surveys looking for anomalous patterns that may point to alien transmissions.

 From article, (So far, SETI has been dominated by radio telescope surveys looking for anomalous patterns that may point to alien transmissions. But SETI’s practitioners are realizing that E.T. may make its presence known in other ways.

Over the next 20 years, or 200 years, SETI may come to stand for sensing extraterrestrial irregularities, ranging from unusual atmospheric chemistry to higher-than-expected thermal emissions. The telltale signs of life beyond our solar system may even be associated with phenomena we haven’t yet come across.

“Two hundred years from now, people are going to look at what we’re doing, and probably laugh and say, ‘Why weren’t they looking for tachyons, or subspace communications,’ or something like that,” Dan Wertheimer, chief scientist for SETI at the University of California at Berkeley, joked during a presentation held at the university in conjunction with the World Conference of Science Journalists in October.

Questions about the potential for life beyond our solar system are much sharper now than they were in 1997, when “Contact” came out, largely because space surveys have established that there could be billions of potentially habitable planets out there.

Anglada-Escudé said the planet search is increasingly focusing in on potentially habitable worlds — such as Proxima Centauri b, the nearest exoplanet, which he and his Pale Red Dot team detected just last year.
Such telescopes could tease out the spectral signatures of alien atmospheres, looking for chemical imbalances that could hint at biological activity. It’s more complex than just finding, say, oxygen or water vapor.

“The detection has taken so long not because we didn’t have the technology, but because we didn’t know where to search,” he said.
Fortunately, more information is on the way — from giant observatories such as NASA’s James Webb Space Telescope, which is now due for launch in 2019; and from smaller, more focused missions such as the Transiting Exoplanet Survey Satellite, to be launched next year.

Now that astronomers know how to check red dwarf stars for potentially habitable, close-in planets, “this is going to be happening more often,” Anglada-Escudé said.Which raises an issue: So far, astronomers have judged the livability of alien planets on the basis of their orbital positions, assumed densities and how much light they get from their parent stars. But to determine whether they’re truly habitable, and whether they have a chance of harboring life, much more information is needed.

Fortunately, more information is on the way — from giant observatories such as NASA’s James Webb Space Telescope, which is now due for launch in 2019; and from smaller, more focused missions such as the Transiting Exoplanet Survey Satellite, to be launched next year.

Such telescopes could tease out the spectral signatures of alien atmospheres, looking for chemical imbalances that could hint at biological activity. It’s more complex than just finding, say, oxygen or water vapor.

“There might be CO2, there might be even molecules we don’t expect to be there at all,” Anglada-Escudé said. “We might see emission features. … When you have the ability to detect methane, oxygen, you can find things that you don’t expect at all.”

Seth Shostak, senior astronomer at California’s SETI Institute, said more powerful telescopes could look for the waste heat given off by highly advanced civilizations, or the radioactive waste left behind by the civilizations that didn’t last.)

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