If you'd asked 20 years ago the question he's heard over and over -- whether humanity will discover extraterrestrial intelligence in his lifetime -- Frank Drake would have shrugged and said, "sure."

Today, the renowned astronomer, who turns 79 next month, admits the chances are slimming.

"It's going to be a close call," he said.

But even if Drake, professor emeritus of astronomy and astrophysics at the University of California at Santa Cruz, doesn't see the day we learn we're not alone, he knows it's coming. To him, it's a mathematical inevitability.

He should know. He wrote the formula. And in a decade when scientists are discovering more extraterrestrial oceans, far away solar systems and Earth-like masses around the galaxy, it's being taken more seriously than ever before.

"The Drake equation gave people a scientific model to start speculating about other civilizations in the galaxy," said Brooks Peck, a curator at Seattle's Science Fiction Museum. "It has so many variables that we don't know what they are. But that's what makes it an ongoing adventure."

At first glance, the nearly 50-year-old formula -- which has turned up in movies such as "Contact," TV series such as "Star Trek" and works of science fiction such as "Sphere" -- looks like something out of physics class. But really, the equation isn't an equation at all, but a way to organize the factors scientists believe could determine how many intelligent extraterrestrial species could come in contact with Earth, like the number of stars with planets, the number of planets that can potentially support life and the number of planets likely to develop intelligent life.

On Saturday, its creator will speak at the University of Washington about two things he's sure of: First, that a series of recent discoveries indicate that life -- if not necessarily intelligent life -- is "very abundant" in the universe. And two, that even though nothing big has turned up in the 50 years the Search for Extraterrestrial Intelligence (SETI) has had an ear to the stars, we need to keep listening.

And listen better.

"People who are not very knowledgeable say that if we've searched and found nothing, doesn't that mean there's nothing there? Shouldn't you give up?" said Drake, Director of the SETI Institute's Carl Sagan Center for the Study of Life in the Universe. "But we've searched just a few minuscule number of stars, on just a few limited channels. Using mathematics, we should not have succeeded yet."

When it comes to scanning the skies for extraterrestrial neighbors, no one has looked longer than Drake. In 1960, as a staffer at the National Radio Astronomy Observatory, he became the first person to conduct a radio search for extraterrestrial intelligence. The following year, he introduced his equation to a small conference of scientists eager to continue the work, despite intense skepticism from their colleagues.

Their work gained notoriety when NASA sponsored projects through the 1970s and '80s, beginning a formal SETI program in 1992 it had canceled by 1994. Though today the SETI Institute relies on grants and donations from wealthy supporters like Seattle's own Paul Allen to listen to the stars for a couple days a year, Drake sees science going his way.

So do his colleagues.

"The idea of extraterrestrial life has undergone a radical shift and Frank Drake has been one of the people that over the decades has made that happen," said Woody Sullivan, a professor of astronomy at the University of Washington who has developed entire courses based on the Drake equation.

The past 10 years have seen a surge of interest in the scientific community in finding extraterrestrial life, Sullivan said, and not just with radios. The new field of astrobiology has risen from the work of geologists, biologists and microbiologists who are taking their studies out of this world, spurred on by encouraging astronomical discoveries -- even if they don't get the same TV ratings as putting a man on the moon.

 

"While there's not as much going on with people heading up to space, going to the moon, or going to other planets, there's so much going on with what we're learning through telescopes and landers," Brooks said. "It's a heyday for space exploration."

On Saturday, Drake will talk about possible discovery of oceans on Jupiter's moon, Europa, the recent launch of the Kepler mission to search for habitable planets, two new Earth-like masses found in the Milky Way and the hundreds of new solar systems that show our corner of the universe might not be as unique as we think.

If it were up to him, he'd build bigger radio telescopes -- lots of them -- and turn them on full blast.

 

"With 200 billion stars in the galaxy, there are 200 billion chances to make Earth," he said. "Everything says it had to have happened many times -- and maybe many more."

Drake will speak at 7 p.m. on Saturday at 120 Kane Hall at the University of Washington as part of the Department of Astronomy's open house. Tickets must be requested in advance here.