This exoplanet orbits the star Gliese 667 C, which belongs to a triple system. The six Earth-mass exoplanet circulates around its low-mass host star at a distance equal to only 1/20th of the Earth-Sun distance. The host star is a companion to two other low-mass stars, which are seen here in the distance.
PALO ALTO, Calif. — The first detection of intelligent extraterrestrial life will likely come within the next quarter-century, a prominent alien hunter predicts.
By 2040 or so, astronomers will have scanned enough star systems to give themselves a great shot of discovering alien-produced electromagnetic signals, said Seth Shostak of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, Calif.
"I think we'll find E.T. within two dozen years using these sorts of experiments," Shostak said here Thursday (Feb. 6) during a talk at the 2014 NASA Innovative Advanced Concepts (NIAC) symposium at Stanford University. [13 Ways to Hunt Intelligent Alien Life]
"Instead of looking at a few thousand star systems, which is the tally so far, we will have looked at maybe a million star systems" 24 years from now, Shostak said. "A million might be the right number to find something."
Many potentially habitable worlds
Shostak's optimism is based partly on observations by NASA's planet-hunting Kepler space telescope, which has shown that the Milky Way galaxy likely teems with worlds capable of supporting life as we know it.
"The bottom line is, like one in five stars has at least one planet where life might spring up," Shostak said. "That's a fantastically large percentage. That means in our galaxy, there's on the order of tens of billions of Earth-like worlds."
Shostak and his colleagues think at least some of these worlds host intelligent aliens — beings that have developed the capability to send electromagnetic signals out into the cosmos, as human civilization does every second of every day. So they're pointing big radio dishes toward the heavens, hoping to detect something produced by living beings.
This search started in 1960, when pioneering astronomer Frank Drake scanned two sun-like stars with an 85-foot-wide (26 meters) West Virginia antenna. It has ramped up considerably over the past half-century, as astronomers have taken advantage of significant advances in electronics and digital technology.
However, getting enough funding to keep scanning the skies is a constant problem. For example, the Allen Telescope Array in northern California — which the SETI Institute uses — was designed to consist of 350 radio dishes, but just 42 have been built to date. And the array had to go into hibernation in April 2011 due to budget shortfalls. (It came back online in December of that year after more funding was found.)
The funding situation colors any discussion of SETI activities and timelines, Shostak said.
The 24-year estimate, for example, "depends on continued SETI funding, which is in dire straits right now," he told Space.com after his talk at the NIAC symposium.
A three-way race to find life in space
The search for alien life does not focus solely on technological societies, of course. Many other scientists are keying in on simple life forms, which must be distributed much more commonly throughout the universe.
The first evidence of microbial life on Earth, for instance, dates from 3.8 billion years ago — just 700 million years after our planet formed. But it took another 1.7 billion years for multicellular life to evolve. Humans didn't emerge until 200,000 years ago, and we've become a truly technological species in just the last century or so.
Shostak thus views the alien life hunt as a three-way race. The contenders are researchers looking for advanced, intelligent civilizations; scientists scouring solar-system bodies such as Mars and Jupiter's moon Europa for simple organisms; and researchers focusing on finding signs of microbial life on nearby exoplanets using future instruments such as NASA's $8.8 billion James Webb Space Telescope, which is scheduled to launch in 2018.
The race may come down to the wire, as Shostak thinks all three approaches could bear fruit in the next few decades.
"I think any of these horses has a pretty good chance of succeeding — just my opinion — a pretty good chance of succeeding in the next 20 years, say," he said during the NIAC talk.