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New York Times October 7, 2009
established a channel of communication, aimed also
Anyone Out There?
at us.
By GIOVANNI BIGNAMI
Look up at the stars and ask yourself: What scares
me more? To be alone in the universe, or to know
that there’s someone else up there?
It’s easy to see that such a channel would probably
use radio waves as the most efficient way of
transmitting a signal. The two men suggested
frequencies for us to listen in on, using the new
It’s an age-old question, as valid for you and me as
antennas of radio-astronomy, just then coming of
it was for Giordano Bruno when he wrote about an
age.
“infinity of worlds” before being burnt at the stake
in 1600.
They had no clue as to what to listen for, of course.
Prime number sequences? Digits of pi? No use
But 50 years ago last month, a letter to the
guessing, just trust them.
magazine Nature ended the passive, look-up-and
ponder attitude by proposing a scientific,
experimental approach. We don’t have an answer
yet (or you and I would know), but in the process
we have come up with quite a tale to tell.
The suggestion of the two physicists fired quite a bit
of enthusiasm. Almost immediately, Frank Drake,
at the newly created National Radio Astronomy
Observatory, started Project Ozma, the first radio
search for an intelligent signal. Since then, over 100
Giuseppe Cocconi (1914-2008) and Phil Morrison
search programs have been carried out, culminating
(1915-2005) were both accomplished physicists
in the biggest of them all, SETI (Search for
when they wrote “Search for Interstellar
ExtraTerrestrial Intelligence), still going strong.
Communications” (Nature, Sept. 19, 1959). Mr.
Cocconi started his life in science doing
experiments with the physicist Enrico Fermi and
later had a brilliant career at the European Particle
Physics Laboratory (CERN) in Geneva. Mr.
Morrison, professor at M.I.T., had been a group
leader in the Manhattan Project.
Their letter to Nature reported the obvious. At the
time, they had no evidence of the existence of
planets around stars and no clue about life on them,
much less on any evolution of technological
societies. But if there are intelligent beings
somewhere out there, they wrote, they may have
All to no avail, of course: not an intelligent peep on
any antenna. Does this mean that we are alone in
the sky? Not at all. As Francis Bacon wrote, “They
are ill discoverers that think there is no land, when
they can see nothing but the sea.”
SETI itself, and its predecessors, have prompted a
small revolution in science, technology and
sociology. Over 50 years, our ability to search for
radio signals has increased 10,000 times more than
the increase in sensitivity enjoyed by all optical
astronomy in the 400 years since Galileo.
SETI has also been able to survive dramatic funding
The only thing we can safely discard is the
cuts, notably from NASA, and is now thriving on
“directed panspermia” theory of Francis Crick and
mostly private support. It does so through the
Leslie Orgel. In 1973, the DNA Nobel discoverer
extraordinary involvement of the public.
and his co-author theorized that “organisms were
deliberately transmitted to earth by intelligent
The enormous computer power necessary to process
beings on another planet.” That would require
all the radio signals collected from the sky is now
enthusiastically supplied by a network of close to a
living matter travelling to us from another star. An
million personal computers. Download SETI
implausible prospect, we now think.
software as your (fascinating) screensaver and you
could, one day, be the first to spot an extraterrestrial
signal — an irresistible prospect to many.
While we are making palpable progress on the
emergence of life, we are definitely stuck on
assessing the chances of life forms being capable of
Meanwhile, astronomy from ground and space has
sending radio signals. We still have a sample of just
found extra-solar planets. The first was discovered
one, our own planet. The visible proof of it, from
in 1995 around a nondescript local star. Nearly 400
the outside, is a sphere of radio and TV waves
more are now catalogued in one of the greatest
expanding in all directions at the speed of light.
leaps of astronomical discovery. We have today a
good insight into the existence of planets: We know
they are the norm, not the exception, around stars.
In the century that has elapsed since Guglielmo
Marconi started sending radio signals, this sphere
must have engulfed the many stars surrounding us
With 100 billion stars in our galaxy alone, we have
within 100 light years. Of course, it has become
ground for optimism about the emergence of life
much stronger in recent decades: In Italy, it is
somewhere else.
affectionately known as the “Berlusconi Bubble.”
Data are accumulating on organic materials in outer
It is debatable whether TV commercials are really
space. Some important building blocks of life, such
the message our civilization wants to convey to our
as amino acids and sugars, are now routinely found
galactic neighbors. What cannot be debated,
in meteorites and in extraterrestrial environments.
however, is the final sentence of the Cocconi and
Recently, NASA brought back some amino acids
Morrison letter, urging us to listen for interstellar
straight from a comet’s tail.
messages: “... success is difficult to estimate, but, if
we never search, the chance of success is zero.”
Complex organic molecules just randomly present
in the stuff our solar system was made from?
Panspermia — the theory that life seeds came from
outer space — confirmed? Too early to tell.
Giovanni F. Bignami, former president of the Italian
Space Agency, is professor of astronomy at
the Instituto Universitario di Studi Superiori in Pavia,
Italy, and the Accademia dei Lincei in Rome.