In hunt for E.T., a giant leap

For years, scientists have been listening for faint whispers of E.T. phoning anyone in electronic earshot. Now, some researchers are hearing sounds almost as exciting - the staccato of hammers, the crackle of arc welders, and the rumble of construction equipment - that signal the building of huge new telescopes to help answer an old question: Are we alone in the galaxy?

The answer to that question looms closer, thanks to boosts in funding, facilities, astronomical discoveries, and advances in technology. Researchers say within a few years they'll be able to conduct far more exhaustive searches for civilizations beyond our solar system.

The field "is in a stage of explosive growth," says Kent Cullers, director of research and development at the SETI Institute in Mountain View, Calif. "I'm not only excited, I'm ebullient."

A decade ago, the idea of searching for intelligent life drew more sneers than cheers in some circles. Congress was skeptical. NASA ended its small-scale program, leaving the search to private efforts. Now, interest is building again.

One factor is scientific opportunity. Astronomers are finding a growing number of planets around other stars - hinting at a potentially vast number of solar systems in the galaxy. NASA is planning two telescopes specifically designed to look for Earth-like planets outside our solar system, which could allow for more-targeted searches.

Another factor is rising technological horsepower. From cheaper, faster computers to devices better able to detect and process extremely weak signals, technologies are allowing researchers to expand their searches beyond radio waves and visible light. At least two new ground-based telescopes are under construction dedicated to the search for extraterrestrial intelligence (SETI). In August, top SETI scientists will meet at Harvard University to look at potential new projects.

Yet for all their efforts, scientists have come up empty-handed. But even that serves as a goad.

"The fraction of the galaxy we've searched ... is incredibly small," Dr. Cullers says - perhaps 700 sunlike stars out of billions. "If we tie ourselves to the growth of computing, within half a century the search will be billions of times larger than it is today."

When US astronomer Frank Drake first turned a radio dish to the heavens to listen for ET signals in 1960, he tuned in only one channel, says Dan Werthimer, an astronomer and SETI pioneer at the University of California at Berkeley's Space Sciences Laboratory. In the 1970s, new receivers could monitor 100 channels at once; today, astronomers can monitor roughly 168 million channels simultaneously - and the number doubles every year, he adds.

The field is also finding new respectability. In its latest 10-year survey of key questions in astronomy and astrophysics and the experiments needed to answer them, a National Research Council panel listed a telescope being built by the SETI Institute and UC Berkeley as a project worth supporting. Although the panel has endorsed SETI efforts in previous reports, its 2001 document was the first to endorse a private, nonprofit SETI effort.

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