Mountain View, Calif.
– A year before Yuri Gagarin orbited the Earth and nine years before Neil
Armstrong set foot on the moon, astronomer Frank
Drake launched one of the most intriguing space explorations of the
millennium.

On April 8, 1960,
in a wind-swept valley near Green Bank, West Virginia, Drake flipped switches,
twisted knobs, and then pointed an 85-foot radio telescope at two nearby
stars – Epsilon Eridani and Tau Ceti. His aim: to ‘listen’ for signs of
communication technology emanating from a civilization beyond Earth.

Drake’s experiment,
named Project Ozma for the mythical princess of L. Frank Baum’s “Wizard
of Oz” books, initiated the modern scientific search for extra-terrestrial
intelligence, commonly known by its acronym, SETI. April 8, 2000, marks
the 40th anniversary of this experiment, which spawned a field of scientific
inquiry and experimentation that continues to capture the imagination
of the world. This year, April 8 is also International Astronomy Day.

Project Ozma followed
on the heels of a ground-breaking paper published the year before by Cornell
University physicists Giuseppe Cocconi and Philip Morrison. That paper
suggested that radio waves might be the most effective means of communication
across galactic distances, and therefore could be the best way to detect
the existence of an extra-terrestrial civilization.

Drake, then an astronomer
at the National Radio Astronomy Observatory in Green Bank, had independently
come to the same conclusion. He also felt he had the means to test the
theory.

“At that time we were
building new, large telescopes, and more importantly, several new forms
of radio receivers had been invented which gave sensitivities about 10
times better than the vacuum-tube based receivers then in common use,”
Drake said. “The combination of the bigger telescopes and the more sensitive
receivers allowed us, for the first time, to detect radio signals from
the distances of the nearest Sun-like stars of the same strength we were
then sending into space.

“To put it another
way, we had crossed a threshold where we could detect civilizations like
our own across the distances which separate the stars.”

Drake remembers that
it was cold in the early morning of April 8.

“We started tuning
these fancy receivers at about 4 a.m.,” recalled Drake, who at the time
was about a month shy of his 30th birthday. “It was nearly freezing. The
tuning had to be done in the feed enclosure, a little larger than a garbage
can, at the focus of the 85-foot antenna. These receivers were new and
very temperamental, and they took about an hour of complicated tuning
to make them work the way we needed them to. Only two people in the world
knew how to do it, the engineer who built them, and myself.”

Project Ozma finally
commenced observations at about 6 a.m. – and almost immediately picked
up a signal.

“We had a big, loud,
false alarm the first day,” Drake said. “Of course, we didn’t identify
it as such until weeks later, and at the time we were very excited. We
couldn’t believe our luck.”

The false alarm turned
out to be a secret military project.

Project Ozma observed
for a total of about 200 hours over a period of two months. Even though
it didn’t detect signals from civilizations beyond Earth, it did prompt
the Space Sciences Board of the National Academy of Sciences to tap Drake
to organize the first major meeting about the search for extra-terrestrial
intelligence.

As an agenda for that
meeting (whose participants included, among others, a young Carl Sagan),
Drake formulated what later became commonly known as the Drake
Equation. The equation, still widely used, is a formula that estimates
the number of civilizations in the galaxy which might be capable of developing
detectable communication technology.

Drake’s pioneering
experiment ultimately led to more than 60 SETI projects, including a major
NASA effort in the 1980s and early 1990s and several experiments in the
former Soviet Union.

Several large SETI
projects continue today. The largest of these, Project Phoenix, is privately
supported and conducted by the California-based SETI Institute, of which
Drake is President of the Board of Directors. Project Phoenix and its
scientists are widely held to be the inspiration for much of the 1997
Jodie Foster film, Contact. Drake also serves as Research Professor of
Astronomy at the University of California-Santa Cruz and, among his many
honors, is a member of the National Academy of Sciences.

Today, Drake is as
active in planning the future of SETI as he was in launching it 40 years
ago. Drake is on the steering committee for a new SETI telescope project.
Planned as an array of small, ‘off-the-shelf’ satellite-style dishes linked
together by sophisticated electronics, the new telescope will advance
SETI by providing more observing time and greater sensitivity to weak
signals. The new telescope will also have numerous applications for general
radio astronomy.

An early prototype
of the new SETI telescope will be launched in mid-April at a site near
the University of California-Berkeley, which is partnering with the SETI
Institute to build the instrument.

“Our equipment today
is 100 trillion times more powerful than the Ozma equipment,” marveled
Drake. “Even so, Ozma wasn’t a waste – it had a real chance to succeed,
even with the technology of the time. And in science you have to advance
by climbing the ladder one step at a time.”
—