years later, the search for intelligent life in the universe
is ready for a shake-up
By Jason Zasky
we alone in the universe? That’s the big question the Search
for Extraterrestrial Intelligence (SETI) seeks to answer,
and so far the answer appears to be yes. In the half-century
since Frank Drake first used a radio telescope to begin
searching for alien radio signals, there has been no message
from ET—indeed, no artificial radio traffic of any description.
SETI researchers argue that SETI has not been a failure,
emphasizing that they have searched just a tiny fraction
of the available space in the galaxy, and that the project
is just getting started. To be sure, the computer revolution
has enormously enhanced our ability to 1) search simultaneously
over many different wavelengths, and 2) filter out manmade
signals, which theoretically increases the odds of a successful
But in the forthcoming book The Eerie Silence (Houghton
Mifflin Harcourt), British-born physicist-cosmologist-astrobiologist
Paul Davies—director of the Beyond Center for Fundamental
Concepts in Science, co-Director of the Cosmology Initiative
(both at Arizona State University), and chairman of the
SETI Post-Detection Taskgroup—argues that SETI scientists
ought to broaden their search beyond “traditional SETI”
(i.e., radio messages) to include a “search for general
signatures of intelligence, wherever they may be imprinted
in the physical universe. And that requires the resources
of all the sciences, not just radio astronomy,” he writes.
I ventured to the Beyond Center in Tempe, Ariz., to meet
with Davies and discuss the themes he explores in The
Eerie Silence. In the following exchange, we covered
issues like: What has SETI accomplished in 50 years? And
what are some of the ways Davies suggests expanding the
In the meantime, the folks at the SETI Institute in Mountain
View, Calif., continue to keep champagne on ice round-the-clock,
in anticipation of the day scientists discover ET.
Why don’t we start by defining SETI?
Fifty years ago, in a famous pilot experiment [at the U.S.
National Radio Astronomy Observatory in Green Bank, W.V.],
Frank Drake first used a radio telescope to see if any messages
from an extraterrestrial civilization might be coming our
way. Using a radio telescope isn’t the only way one can
look for signs of intelligent life elsewhere in the universe,
but it’s the most obvious way, because radio telescopes
have the power to communicate across interstellar distances.
So SETI, as it’s usually interpreted, is this radio telescope
What has been accomplished in 50 years?
The title of my book—The Eerie Silence—says it all.
There has been no definitive message from any civilization
or indication of any artificial radio traffic. There have
been a few intriguing “don’t knows” [the “Wow” signal, a
72-second pulse detected on Aug. 15, 1977, as well as a
half-millisecond blip known as Lorimer’s pulse]—transient
events that are difficult to evaluate after the fact. But
nothing where one can say: If you point your radio telescope
to a certain part of the sky you’ll pick up a bleep-bleep
from what looks like an artificial source.
However, Drake’s pioneering experiment was done with Steam
Age technology. Since then the computer revolution has enormously
increased our ability to search simultaneously over many
different wavelengths and to filter out manmade signals.
It is no longer necessary for an operator to sit at the
controls, steer a dish, and listen on a loudspeaker. It’s
all done by computers, and astronomers put their feet up.
How do SETI researchers keep from getting discouraged?
They are irrepressible, aren’t they? I think most of them
take the point of view that they are doing good astronomy
anyway. They are using state-of-the-art equipment and developing
algorithms for searching through the signals, which is useful
to do anyway. And they can always think that with improvements
and more money they eventually will pick something up.
Who pays for SETI research?
It’s almost all paid for by private donations. And the total
cost is very modest by the standards of almost any sort
of scientific venture. It’s a drop in the ocean compared
to what is being spent on other things.
In the book, you write about your belief that traditional
SETI is stuck in a conceptual rut.
Everyone is still enthralled with Carl Sagan’s vision, his
idea being that there is a civilization out there that guesses
we’re here, beams a message at us using what in technical
jargon is called a narrow-band signal, and all we have to
do is tune in and get the message and all sorts of wonderful
consequences will ensue. I don’t think that is credible.
We need to look for signatures of intelligence wherever
we might see them. And when it comes to radio, I think we
should refocus to look for beacons, not narrow-band signals.
The SETI community is slowly buying into this, but the majority
of SETI has been with a narrow-band signal.
How is it that something as bold and visionary as SETI became
stuck in a rut?
It is remarkable, isn’t it? But I suppose the difficulty
of the task means you have to focus on a particular strategy
and then refine it and refine it. There’s always that tendency
in science. What you’re good at, what you understand, you
do more of the same.
How extensively have SETI researchers searched thus far?
They have looked in a little bubble around our neighborhood,
which is why the title of my book irritates the SETI people,
who say, “What do you expect? We’ve only been doing it for
50 years.” But if you’re an optimist and you apply Moore’s
Law to this, then within a few decades researchers can probably
search the whole galaxy, and then the science will become
much more significant. It’s too soon to say it’s a waste
of time to carry on with traditional SETI. I think it’s
a great thing, but maybe after 50 years the public might
be thinking, “Can we try something else?” And I think we
should. We should think much more expansively about what
a signature of intelligence might be. Forget messages, all
we really want to know is: Is anyone out there? Their presence
could be betrayed in a large number of ways.
The public seems to assume that alien life, if it exists,
would be reminiscent of human life. But biologists have
recently discovered microbes living under extreme conditions.
What’s to say that intelligent alien life can’t live under
This is where you’re on a sliding scale of speculation.
The first speculation is: Maybe there’s alien life, but
it’s life as we know it. Let’s be conservative and assume
that life elsewhere would follow the pattern here. It would
be carbon-based, require liquid water, would evolve over
billions of years, and so on. Then you end up with the familiar
features. We could easily speculate about radically different
forms of life. Whether radically different forms of life
could ever become intelligent is another matter. And if
we encountered alien technology we might not be able to
recognize it. There are some who go so far as to say that
the entire universe is a product of alien technology, and
the reason it all looks so gee-whiz and works so well is
because it’s designed to do exactly that. But leaving aside
that sort of wild speculation, the difficulty is to know
how really advanced technology would manifest itself in
a way that would make us sit up and take notice, without
us saying, “It’s a miracle!” That’s difficult because it
requires us to think way beyond our current level of technology.
We somehow have to keep our feet on the ground while staring
into the sky.
In the book you discuss how advances in technology have
changed our thinking—or should change our thinking—in regard
to SETI. Can you elaborate?
First was the laser, most significantly. I think people
[now] feel that ET would probably use laser signaling rather
than radio signaling. More recently people have suggested
more exotic types of signaling—neutrinos being one possibility.
I still feel that radio is probably best. But we might find
evidence of alien activity that’s not a message, but a footprint
There is another scenario, one which has nothing to do with
electromagnetic or neutrino signaling, which is that ET
might use biological organisms as a means of sending information.
Genomes are packed full of information. If you could get
a message into a cell somehow, it would just replicate and
replicate. If you could do that in a way that doesn’t compromise
the biological functionality of the host then you’ve got
something that could endure for millions and millions of
years. So rather than sending radio messages, I would be
in favor of, for example, dispatching viruses—retroviruses—that
would insert DNA into any DNA-based organisms. It costs
nothing to search the genome, because people are sequencing
genomes anyway. So why don’t we search as many genomes as
we can get our hands on, not just human—just to see. It’s
a crazy idea, but then all of SETI is slightly crazy. I
believe we should do what we can do easily and cheaply even
if the chances of success are exceedingly small.
What about the idea that aliens might be postbiological
I believe that biological intelligence is a very transitory
phase in the evolution of intelligence. If we, for example,
get through the next few decades—the bottleneck we’re facing
now in terms of energy and environment—we will see more
and more a transition to transhumans and to human machine
systems and ultimately to all-machine-type systems. The
smartest entities on the planet will not be flesh and blood.
I’m sure that would be true of an advanced civilization
We should get away from this Hollywood image [of alien life].
I went to see Avatar, which is spectacular for its
3D wonderworks but pathetic for its storyline. It commits
all the usual sort of fallacies. Explain the implications
of the speed of light on SETI, which seems an oft-overlooked
factor. Yes, it has been brushed aside, and many science-fiction
fans overlook the speed of light. But if you believe the
theory of relativity—which almost all scientists do—then
this is the fastest speed in the universe. Any type of physical
interaction is limited to the speed of light. And though
it’s fast by everyday standards, it’s slow by astronomical
standards. It takes light about eight and a half minutes
to reach us from the sun; it takes over four years to reach
us from the nearest star; it would take a hundred thousand
years to reach us from the other side of the galaxy. The
relevance here is that even in principle, our existence
cannot be known beyond a certain distance. For example,
a hundred light years away, an observer would see Earth
as it was a hundred years ago. So the existence of a technological
community on Earth—at the very least having radio capability—could
not, even in principle, be known beyond a few dozen light
years from Earth. If there was an advanced civilization
within that distance, it’s not inconceivable that they have
picked up our first radio messages and beamed something
our way. But even SETI optimists don’t think there’s likely
to be a civilization that close. I like to take a thousand
light years as a good sort of guesstimate.
When you put this to people who do SETI they reel around
a bit, and say we could be dealing with a civilization that
is so altruistic that it is prepared to beam messages to
Earth based on a mere expectation that there might be [intelligent
life here] in a few centuries or few millennia. It would
make much more sense for them to wait for our first signals.
They might as well just monitor us passively and then start
beaming messages. I think the best we can hope for is to
pick up a beacon that is broadcast to no one in particular—or
stumble across somebody else’s messages going back and forth,
much like eavesdropping on a telephone line. You have to
be jolly lucky to be in the way, of course. Is SETI science
When it began I think a lot of people felt it was pseudoscience;
one might as well have expressed a belief in fairies, to
be perfectly honest. But over the years it has become more
respectable, and the SETI Institute now has a lot of joint
projects with NASA, and many of these are astrobiology [as
opposed to SETI]. So I think it qualifies for being a science,
but ultimately we must have the usual standards of verification,
and it’s obviously very speculative. It’s speculative even
by the standards of modern physics, which has a lot of weird
and wacky stuff swirling around.
So I would like to distinguish between the practice of SETI
and the conceptual basis of SETI. The practice of SETI is
thoroughly scientific. When you talk to the astronomers
concerned, these are professional scientists, and their
day-to-day work is of the highest standard. There isn’t
any doubt that they are going about their work in a scientific
way. But the agenda itself is marginal. It’s very much on
the fringes of what can be considered scientifically respectable.
What makes it acceptable to look for aliens, but not ghosts?
This is very subtle but it has to do with the conceptual
framework in which you fit it. Physics provides the best
example. When physicists go looking for the Higgs boson—as
they are at the moment at the Large Hadron Collider—there’s
a good body of theoretical work that has gone into that
expectation, with precise predictions, even though it may
not be there. The same is true for the neutrino, the famous
ghostly particle that was postulated in the 1930s but wasn’t
definitively identified until the mid 1950s. Why did people
spend time looking for this ghostly entity? It’s because
it had a well-defined place in physical theory.
So when it comes to looking for aliens, we have to convince
ourselves that it’s a rational thing to look for. Some people
might take the view that it’s a crazy and pointless exercise,
but at least in the case of extraterrestrial life we know
the sort of thing it is and can understand how it would
evolve. When it comes to ghosts, to take your example, there
is no credible theory. We can make no realistic predictions
of where to look or how to look. We can’t fit it in to a
large body of scientific knowledge. That doesn’t mean there
are no ghosts. When it comes down to this shot in the dark,
if you look for something that connects to an enormous body
of well-defined, believable theory and experiments, it’s
very different from plucking something that doesn’t belong
to science and saying, “We’ll look for that too.” It’s clear
you feel that SETI—including traditional SETI—is still worth
pursuing, even though the odds of success are long.
While the chances of success are very small, the consequences
would be enormous. If they [SETI scientists] succeed, it
will probably be the most momentous scientific discovery
in history. So to allocate some small fraction of the world’s
resources to addressing such a very deep question is certainly
justified. And even if SETI fails, it’s very healthy that
we address issues like: What is nature? What is humanity?
What is our destiny? What do we mean by life? What do we
mean by intelligence? What is our place in the universe?
These are all good things to think about, even if we never
pick up a signal.
Zasky is the founder and editorial director of failuremag.com,
where this interview first appeared.