Some professors like to communicate with students—others, with aliens.

Physics and Electrical Engineering Professor Paul Horowitz ’65 says he’s convinced that communicating with extraterrestrial life will soon be within scientists’ reach.

Horowitz, who has taught physics at Harvard since 1974, is a leading figure in the official Search for Extra-Terrestrial Intelligence (SETI)—a national project devoted to identifying intelligent life outside our galaxy, with hubs at Harvard and Princeton.

Lounging in his newly renovated office in Jefferson Lab, Horowitz says he is excited about the future of SETI and his own involvement in the search.

“We’re basically asking how would we communicate with these intelligent life forms without going over to [visit] them on a rocket,” Horowitz says.

And he quickly debunks the notion that extraterrestrial life is unworthy of academic investigation.

“They’ve found that at least 100 planets exist outside our solar system. What happened here [on Earth] is probably very typical,” he says. “Somewhere, the magic happens that leads to self-reproducing organisms.”

Horowitz says people first became interested in extraterrestrial life in the mid-19th century.

But he points to the discovery of the radio telescope in the 1960s, which he began working with in the 1970s, as the time when people realized communication over galactic distances might be possible.

The discovery, Horowitz says, seemed the perfect alternative to expensive space travel and past attempts to measure charged particles, which bend in magnetic fields such as those in space.

Beam Me Up

Recent developments, however, have demonstrated the superiority of optical laser SETI over radio—and Horowitz has helped pioneer this technology.

He explains that extraterrestrials are most likely contacting humans by aiming laser beams at receivers on earth. These beams, Horowitz believes, will illuminate their planet or star of origin to a level 5,000 times brighter than the sun.

“When a laser pulse is aimed from a certain star, the star illuminates for a moment so that we can see it,” he explains. “We only do receiving.”

Horowitz says that he and physics graduate student Andrew Howard use a complex optical telescope to search the night sky for such flashes of light. The telescope has sensitive light detectors at its focus and measures five feet across its bottom.

The actual optical telescope is operated by a team at the Oakridge Observatory in Harvard, Mass.

While Horowitz says he has detected some flashes, he has yet to confirm their extraterrestrial origin.

Horowitz says that he can currently only observe a limited number of targeted stars but looks forward to developing what will be called the All-Sky telescope within a year or so.

This telescope, which will be complete once a detector apparatus is installed, will be able to observe the entire sky—10,000 times more area than the team currently covers.

“We’re only myopically looking at stars now,” he says.

He anticipates the All-Sky will allow his team to investigate not only stars, but the spaces in between them where he suspects that advanced civilizations may roam between various stars and planets.

He adds that his research is focused on “calculation, not speculation” and brims over with enthusiasm for the optical SETI.

Light Years Away?

Howard and Horowitz work concurrently with researchers at Princeton who make simultaneous observations. Each team generates observational diagrams, including the stars observed, the number of observations made and the signals detected.

According to Howard, the teams’ findings always match.

“Combined, the two results have never produced a false positive,” he says.

Jill Tarter, the Bernard M. Oliver Chair for SETI at the SETI Institute in California, calls the project with Princeton “very innovative and clever.”

She describes the Sky Survey instrument Horowitz already uses as “typically Paul—typically creative and inventive.”

To Horowitz, the future of SETI seems both daunting and enthralling.

“SETI hasn’t succeeded yet, so it’s clearly got a ways to go,” he says.

Of the 20,000 observations his telescope has made, Horowitz says, no decidedly conclusive observations have been reached.

Still, he says that he and Howard are excited about the coming years.

“We like trying new and different things,” he says.

Other astronomers, such as Dr. Joseph Lazio of the Naval Research Laboratory, are more skeptical of the project’s short-term success, but affirm the significance of the study.

“Will we have success in the near future? Define ‘near,’” he says. “In the next 100 years? Many astronomers are hoping that in the next 20 years, we’ll be finding Earth-like planets.”

Tarter also says she foresees some difficulties with Horowitz’s All-Sky project, namely the unpredictable New England weather.

“Can you do something about the weather in Massachusetts?” she asks jokingly. “You need a lot of clear nights for the survey, and it’s going to take a lot of time to get 100 clear nights.”

Still, Tarter says she supports Horowitz’s general project.

“All this UFO, alien abduction garbage attached to SETI [is] what makes money, what people find sexy,” she says. “But the real SETI is a valid scientific exploration.”

She reminds any naysayers of the project’s monumental significance.

“We have this opportunity now to answer the age old question: are we alone? I feel very privileged to do something which might have some impact on society,” she says.

Horowitz says it is that very possibility that motivates him to keep searching the sky each night.

“My long view is, it’s not a question of ‘if,’ it’s a question of ‘when,’” he says. “We’re gonna contact them someday.”

—Staff writer Rebecca M. Milzoff can be reached at milzoff@fas.harvard.edu.