Tuesday, September 05, 2006

Increasing Computing Power Makes Likelihood of Finding ET Greater

BY John Jerney
The Daily Yomiyuri

Seth Shostak Cropped SETI     Are we alone in the universe? Is man the only intelligent life form? (No e-mail about that, please.) Is anyone else out there?

Dr. Seth Shostak, senior astronomer at the SETI Institute, thinks that someone may indeed be out there. In fact, ET could be trying to call us right now and, consequently, we should probably be listening.

SETI, as you probably know, stands for the Search for Extraterrestrial Intelligence. And leading the search is the SETI Institute based in Mountain View, Calif., a collection of more than a hundred scientists, radio astronomers, and astrobiologists, about 20 of which are actively hunting for the ultimate long distance call.

Part of the challenge in finding a signal is that we are expecting ET to think along similar lines as us. "Of course we're biased," Shostak said during a recent conversation in his office at the institute.

"We think that an extraterrestrial intelligence will actually create a transmitter that can produce a signal that we can find. And that bias means that we're not going to find Neanderthals, and we're not going to find Romans and classical Greeks, 'people' like that."

It also probably means that we are going to miss the shout out from ultra advanced civilizations that have either discovered a more efficient or faster mode of communication, or have evolved to be just smart enough to know to keep quiet.

But for the rest of them, the search continues.

Another part of the challenge has been the cost of building radio telescope receivers capable of scanning a large enough part of our intergalactic neighborhood.

"In the old days, if you built a radio telescope, it would cost you on the order of a million dollars for the receiver. So you couldn't build a whole lot of them," Shostak said. "Even though building a lot of small radio telescopes is cheaper than building a large one, the cost of the electronics dictated that you had to build as big a telescope as you could."

Or you built a collection of medium-sized radio telescopes, such as the Very Large Array in New Mexico. Featured in movies, such as "Contact," starring Jodie Foster, the Very Large Array has 27 antennas, which traditionally has been considered a large collection.

But all this is changing. "The electronics have gotten approximately two orders of magnitude cheaper," Shostak said, "and this means that the electronics no longer costs a million dollars per antenna. Instead, it costs something on the order of tens of thousands of dollars. So that means that it's now much cheaper to build radio telescopes out of lots of small antennas."

And that is exactly what the SETI Institute is doing with the Allen Telescope Array, an impressive and forward-looking endeavor currently being built at the Hat Creek Radio Observatory in Northern California.

Named after Microsoft cofounder Paul Allen, who donated more than 10 million dollars to sponsor the initial research and development and build the first dishes to test the proof-of-concept, the Allen Telescope Array will feature an amazing 350 antennas when it is completed in the next few years. Each dish in the array will measure a modest six meters in diameter.

The first 10 antennas of the Allen Telescope Array are currently undergoing commissioning. "It turns out that using a lot of small dishes is more flexible anyway," Shostak said. "It has all sorts of advantages in terms of the science, but also when we get additional money, we can keep expanding the telescope."

But there is more about the Allen Telescope Array that jazzes Shostak. "What it gives you right away is 24/7 observations. That right there is an order of magnitude increase in speed. Now everything is 10 times faster than it was, and 10 times is an interesting number," he said.

The second thing that the Allen Telescope Array promises to offer is increased flexibility. "Because it is an array," Shostak said, "it is really an imaging instrument. At Arecibo [the massive 305-meter radio telescope in Puerto Rico], you point it at one star system, and an hour later you point it at another star system.

"With the Allen Telescope Array, you actually get a raster of radio pixels of the sky. And you can put those pixels anywhere you want in a big field of view; it's not like a digital camera where they are all in a nice matrix. So you can look at five stars at once, or 10 or even a hundred, if you have enough compute power."

And with computing power expected to increase according to Moore's Law (which means doubling in speed every 18 months or so) for at least the next decade, that adds another order of magnitude of speed. "Those are the two big wins that multiply together to give you an experiment that is perhaps a hundred times faster than what you could do before," Shostak said.

Ultimately, Shostak thinks the chance of success is quite high.

"Over the next two dozen years, the Allen Telescope Array will look at, on the order of, a few million star systems. To date, we've looked at fewer than a thousand," he said. "So that's three orders of magnitude more, almost four. And I think that's the right number. If the postulates of SETI are correct, and no one knows if they are, then success is not generations away. It could happen a lot sooner."

So what happens if and when we find a signal and verify its extraterrestrial origin? Shostak is not sure. "That's a sociological question. And nobody knows the answer to that because we don't have any historical analogues," he said.

While Shostak thinks a discovery could have profound effects, he does not think it will necessarily lead to a massive upheaval. "And part of the reason for that is that one-third of the American population, for example, not only believes that the aliens are out there, they think the aliens are already here," he added.

Well perhaps. But personally, I think we're more likely to pluck a signal from the stars than to be plucked up from space.

More . . .

See Also: Shostak Responds to Recent "SETI Politics" Article


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