E.T., Why Don't You Just Call?

PHOTO Allen Telescope ArrayCourtesy Seth Shostak, Senior Astronomer, SETI Institute

An innovative new radio telescope has given new life to the search for extraterrestrial intelligence, leading one of the leaders of the search to make a bold prediction.

"We'll find ET within two dozen years," Seth Shostak, senior astronomer at the SETI Institute, proclaimed in a speech at the California Institute of Technology. Shostak went on to say that he not only has a pretty good hunch about how long it could take, he thinks he knows what ET will be like.

But don't expect him to look like us.

"I think that if there's a conscious intelligence out there, it's synthetic," Shostak added. He's talking robots, folks. The argument goes like this: Darwinian evolution is a very slow process, and although it probably has occurred on many planets, it has it's limitations -- like us. Technological evolution, by contrast, can advance at warp speed, as we've all seen in the computers that are out of date by the time we get them out of the box.

Thus, any biological life, like us, will eventually lose out to the machines we create, and synthetic intelligence will take over where we leave off. The real challenge, of course, will be to keep the robots under control but still let them do our thinking for us, a neat trick if we can pull it off.

It's probably going to happen, Shostak said, because technological evolution "just blows Darwin away." So, ET not only should be out there someplace, he should be one really smart machine.

Now, predictions about how long it will take to find ET are not rare, since that's probably the most common question put to scientists at the SETI Institute, a private, nonprofit organization dedicated to the search for intelligent life elsewhere in the galaxy. The institute has been the largest player in the search since NASA abandoned a formal program several years ago. The space agency has continued searching for other Earth-like planets, including the launching of the Kepler telescope last March, but it has shied away from looking directly for ET.

What makes the search different now is the creation of the Allen Telescope Array in a dusty valley 290 miles northeast of San Francisco that will, for the first time, look for ET 24 hours a day, seven days a week. Only 42 of the planned 350 radio dishes that will make up the array have been completed, but that's enough for scientists to begin combing the heavens for many secrets, including the hiding place of ET.

The array is a joint project by the University of California, Berkeley, and the SETI Institute. The primary financial support has come from Paul Allen, co-founder of Microsoft, who put up $25 million in seed money in 2001.

The array is the first panchromatic, wide-angle, snapshot radio camera ever built, according to scientists at Berkeley. The design is based on the idea that it's cheaper to build a lot of small radio antennas that act as one than it is to build huge dishes.

As part owner of the new array, SETI finally has its own toolbox and scientists will no longer be forced to use "other people's telescopes, which is like doing cancer research with borrowed microscopes," Shostak said.

Shostak's optimism is based partly on the availability of the array, and partly on the fact that new planets are being discovered outside our solar system on about a monthly basis. They are not all capable of sustaining life as we know it, but some of them may be. That has lead many scientists to speculate that life, and possibly intelligent life, abounds throughout the universe.

But that contributes to one of the debates that have plagued SETI over the years. If there are lots of other planets out there like ours, with living creatures that are at least smart enough to build radio transmitters, why haven't we found them? SETI may not have had all the tools it needed, and funding has been scarce, but lots of very smart people have been looking very hard for ET for several decades.

Some astronomers dismiss those questions by noting that there's just zillions of places to look, and they are a long ways away, and no one is certain what to look for. So in the past, searchers have counted on finding radio signals that are beamed our way by someone on another planet who is looking for us.

It would probably have to be a directed beam because "leakage," like from television broadcasts, would be too weak. Besides, why would someone who is so much smarter than us broadcast over the air when fiber optics are more reliable and efficient? Our own electromagnetic signature is shrinking, Shostak noted in his talk, so we're not likely to stumble across ET's version of "ABC News with Charles Gibson."

But new tools, including the Allen Telescope Array, could open new ways to search for ET. Unlike other radio telescopes, the array can image a huge piece of the sky at once, or concentrate on a single star with an interesting planetary system. All objects in space emit radio waves, which can reveal much about their composition.

One way to narrow the search is to look for some of the things produced on Earth that would not be here if there had been no life. Methane, Shostak noted, would disappear from a planet's atmosphere in a relatively short time, so if it's there, something must be producing it.

"Much of the methane in this room is produced by what is politely called 'bovine flatulence,' and also by porcine flatulence, so this technique would at least allow you to find pigs in space," he added. But, of course, they would not necessarily be smart pigs.

It is widely believed that water would have to be present on another planet for it to support life, and scientists at the University of Washington have devised a technique that they say would determine if another planet has oceans. Using instruments aboard a NASA spacecraft, the scientists studied light intensities from Earth in seven bands of visible light from near ultraviolet to near infrared.

They found two dominant colors, blue and red, and surmised that the red came from land masses, and the blue from oceans. If they could detect the same colors from a distant planet, they would have evidence that the planet had huge areas of water, the scientists said in an article that is scheduled for publication in Astrophysical Journal.

"Liquid water on the surface of a planet is the gold standard that people are looking for," said Nicolas Cowan, a doctoral student in astronomy and lead author of the paper.

Of course, oceans do not necessarily mean life, especially intelligent life, but such a discovery would help focus the search on more promising planets. It will, however, require a new generation of space telescopes.

And if Shostak is right, we may already know by then.

"If we don't find ET within a generation, there is something very fundamentally wrong with our assumptions," he said in his talk, which was published in Caltech's quarterly, Engineering and Science.

It would make things a lot easier if ET would just give us a shout.