<em>Should we ever hear the space-phone ringing, for    God's sake let us not answer...</em>

<strong>Meet the neighbours: Is the search for aliens such a good idea?</strong>                       <span class="starrating">       </span>

<em> We've been trying to make contact with aliens for years. Now the day is fast approaching when we might finally succeed. But will our extraterrestrial friends come in peace? Or will they want to eat us? Astronomer David Whitehouse explores the perils of a close encounter</em>

<a href="http://comment.independent.co.uk/commentators/article2702529.ece" target="_blank">Independent</a> 25 June 2007

We are making dangerous discoveries in space. In April, astronomers found, on our cosmic doorstep, a planet dubbed Gliese 581c. Nestling close to a dim red star, it's a rocky world only a little larger than Earth. Like Earth, it could support liquid water. And to scientists, liquid water means the possibility of life.

Gliese 581c must be an ancient world, for it circles a star that is far    older than our Sun. The question is, has any advanced life evolved on that    planet, or on the many other places that must be suitable sites, not so very    far away?

Recently, British astronomers told the government that we might find life in    space. It is only a matter of time, this year perhaps, before astronomers    detect a planet even more similar in size and mass to our Earth, circling    another star. And when we find that planet, we may discover a lot more than    new oceans and land masses.

Astronomers have been actively looking for intelligent life in space since    1960, when Frank Drake started Project Ozma, using a radio telescope to    listen for signals from two nearby sun-like stars - Drake knew that radio    waves travel more easily through the cosmos than light waves. He didn't hear    anything back. Since then, our searches have become more thorough thanks to    larger radio telescopes and more sophisticated computers that look for    fainter signals. But we still have no signal from ET. Should we want to?

<!--more-->This is not just a matter for astronomical research involving distant worlds    and academic questions. Could it be that, from across the gulf of space, as    HG Wells put it, there may emerge an alien threat? That only happens in    lurid science fiction films, doesn't it? Well, the threat is real enough to    worry many scientists, who make a simple but increasingly urgent point: if    we don't know what's out there, why on Earth are we deliberately beaming    messages into space, to try and contact these civilisations about whom we    know precisely nothing?

The searchers are undeterred. They argue that because of the vastness of    space - even if there are 10,000 transmitting societies nestled in the    stellar arms of the Milky Way - we might have to search millions of star    systems to find just one.

But rather than just listening, some want to announce our presence to the    cosmos. In 1974, the then newly resurfaced Arecibo radio telescope in Puerto    Rico (made famous in the James Bond film Goldeneye) reversed its usual role    of just listening, and transmitted a series of radio pulses towards the M13    star cluster. It sent 1679 pulses in all, which, when arranged in binary    form into 23 columns and 73 rows, would form a message from humanity. It was    seen as a symbolic gesture, showing those on Earth that we had the    technology to send a signal across our galaxy and - if we were on the other    side of the relationship - to receive a signal as well. But some scientists    objected. Sir Martin Ryle, the Astronomer Royal at the time, warned that " any creatures out there [might be] malevolent or hungry".

Now, after a long period when there were no deliberate transmissions into    space, a new round is about to take place and more are planned. A team led    by the astronomer Alexander Zaitsev has already beamed forth a series of    interstellar messages, including pictorial and musical transmissions, from    the Evpatoria radio telescope in the Ukraine. Another group in Brazil, the    Grupo Independente de Radio Astronomos in Rio de Janeiro, claims to have    transmitted as well. Half a dozen commercial companies have also sprung up,    among them Cosmic Connexion, a firm based near Cape Canaveral in Florida.    The Cosmic Connexion website invites you to e-mail your messages to them and    they will then beam them, free, into space and "introduce you to    extraterrestrials". At the moment, though, this is a low-power    initiative whose signals won't get far. Other companies offering the same    service for a fee are soon to come online.

Many scientists, frightened by the danger that might lurk out there, have    argued against our actively seeking contact with extraterrestrials. Jared    Diamond, professor of evolutionary biology and Pulitzer Prize winner, says: " Those astronomers now preparing again to beam radio signals out to hoped-for    extraterrestrials are naive, even dangerous."

The fact is, and this should have been obvious to all, that we do not know    what any extraterrestrials might be like - and hoping that they might be    friendly, evolved enough to be wise and beyond violence, is an assumption    upon which we could be betting our entire existence. When I was a young    scientist 20 years ago at Jodrell Bank, the observatory in Cheshire, I asked    Sir Bernard Lovell, founder of Jodrell Bank and pioneering radio astronomer,    about it. He had thought about it often, he said, and replied: "It's an    assumption that they will be friendly - a dangerous assumption."

And Lovell's opinion is still echoed today by the leading scientists in the    field. Physicist Freeman Dyson, of the Institute for Advanced Study in    Princeton, has been for decades one of the deepest thinkers on such issues.    He insists that we should not assume anything about aliens. "It is    unscientific to impute to remote intelligences wisdom and serenity, just as    it is to impute to them irrational and murderous impulses," he says. " We must be prepared for either possibility."

The Nobel Prize-winning American biologist George Wald takes the same view:    he could think of no nightmare so terrifying as establishing communication    with a superior technology in outer space. The late Carl Sagan, the American    astronomer who died a decade ago, also worried about so-called "First    Contact". He recommended that we, the newest children in a strange and    uncertain cosmos, should listen quietly for a long time, patiently learning    about the universe and comparing notes. He said there is no chance that two    galactic civilisations will interact at the same level. In any    confrontation, one will always dominate the other.

The Australian astronomer Ronald Bracewell, now of Stanford University,    warns that other species would place an emphasis on cunning and weaponry, as    we do, and that an alien ship dispatched our way is likely to be armed.    Indeed, evolution on earth is, as they say, red in tooth and claw. And it's    likely that any creature we contact will also have had to claw its way up    its own evolutionary ladder and may possibly be every bit as nasty as we are    - or worse. Imagine an extremely adaptable, extremely aggressive    super-predator with superior technology.

So should we stay quiet and ban these transmissions into space? When, as a    newly minted young scientist, I was discussing this issue with the (late)    influential astronomer Zdenek Kopal, he grabbed me by the arm and said in a    tone of seriousness: "Should we ever hear the space-phone ringing, for    God's sake let us not answer. We must avoid attracting attention to    ourselves." Others have put it more graphically, saying that the    civilisation that blurts out its existence might be like some early hominid    descending from the trees and calling "here kitty" to a    sabre-toothed tiger.

But not all scientists are worried. Frank Drake, who devised Project Ozma    and who was also behind the Arecibo transmission says, "As I thought in    1974, the objections to sending interstellar messages were naive and carried    no weight. The argument then, as now, is that humanity has been, and is    making, its presence known through our TV and radio and military radars    which, in many cases, release most of their radiated power into interstellar    space."

Radio waves from Earth, from TV and radio broadcasts and from powerful    intercontinental military radars are leaking out into space. Some believe    they could be detected, but should we go beyond this and actively announce    our presence to the cosmos? Drake points out that our present terrestrial    radio telescopes, if placed on nearby worlds, would be unable to detect    these transmissions at distances beyond a few light years. However, aliens    would be more advanced, he says, and it is quite within the abilities of    current terrestrial technology to build telescopes, using the array    approach, which could detect these transmissions from great distances in the    galaxy.

"The point here is that Earth has made its presence known by sending a    multitude of signals. It is too late - we have made ourselves visible,"    he adds.

But scientist and science-fiction author David Brin thinks those in charge    of drafting policy about transmissions from Earth - ostensibly a body called    the International Astronomical Union, which would make recommendations to    the United Nations - are being complacent, if not irresponsible. Whatever    has happened in the past, he doesn't want any new deliberate transmissions    adding to the risk. "In a fait accompli of staggering potential    consequence," he says, "we will soon see a dramatic change of    state. One in which Earth civilisation may suddenly become many orders of    magnitude brighter across the Milky Way - without any of our vaunted    deliberative processes having ever been called into play."

Michael Michaud, a former US diplomat and chairman of the Transmissions from    Earth Working Group - a subdivision of the International Astronomical    Union's Search for Extraterrestrial Intelligence Study Group established in    2001 - is on the verge of resigning in frustration at the lack of discussion    about the problem. He believes it is being confined to a narrow group of    scientists who share the same limited astronomical viewpoints and he wants    the study group widened beyond its current remit to include planetary    scientists, philosophers, historians and so on. He sees it as a problem that    affects all of humanity - and one that should be debated as such.

But despite these concerns, for the moment, the plans for deliberate    transmissions from Earth go ahead and there is nothing anyone can do to stop    them - or even demand a discussion beforehand.

One thing is clear from our searches for ET - there is nobody transmitting    strong interstellar beacons in our local vicinity. If "they" are    out there, they are keeping quiet, prompting the question that they might    know something we don't.

Perhaps the aliens already know about us and are on their way. Or perhaps    not. Intelligences - possibly vast, cool and unsympathetic - could be    sweeping their skies looking for us. At the moment when they point their    instruments in the direction of our sun - a commonplace yellow-dwarf star -    they may well find nothing unusual, if no one's sending messages in the    other direction. Should we keep it that way?

<strong>Searching for ET: the truth is out there</strong>

The Seti (Search for Extra-Terrestrial Intelligence) Institute in California    is the only such group that searches the cosmos for signs of intelligent    alien life. It does so by listening out for radio signals.

Seti, which was founded in 1984, has 100 scientists, educators and support    staff. Its funding from the American government was cut off in 1992 and it    now relies on private donations.

The institute's Project Phoenix was the most ambitious search for    extraterrestrial intelligence ever undertaken. From February 1995 to March    2004, Phoenix conducted three observing campaigns on some of the world's    largest radio telescopes, targeting stars within 240 light years of Earth.

In more than 11,000 hours of observing, using telescopes in Australia, West    Virginia and Puerto Rico, Project Phoenix "tuned in" to more than    800 stars. No ET signals were detected.

The next stage in the search is the Allen Telescope Array, currently under    construction in California. Partly funded by the Microsoft billionaire Paul    Allen, it will eventually consist of 350 20ft dishes making synchronised    sweeps of the sky looking for alien signals (see www.seti.org).

<strong>Postcards to the edge</strong>

ARECIBO (1974)

This message was sent from the Arecibo radio telescope in Puerto Rico to the    M13 star cluster, 25,000 light years away (150,000 million million miles).    Consisting of 1,679 binary digits, the bits can be arranged into a rectangle    of 73 rows and 23 columns (two prime numbers) to reveal a message.

Encoded are: the numbers one through to 10; atomic numbers of key elements    such as hydrogen, carbon and oxygen; a graphic of DNA, along with an    estimate of its complexity; a graphic figure of a man and the human    population of Earth; a graphic of our solar system; and a graphic of the    Arecibo radio telescope.

The signal took 169 seconds to send and was not repeated.

COSMIC CALL (1999, 2003)

The first public interstellar messages were sent from the Evpatoria Deep    Space Center in Ukraine. Signals were sent twice in 1999 and once in 2003    towards five nearby Sun-like stars about 50 light years away. The 1999    message consisted of 23 black and white stylised images starting with the    basics of mathematics and ending with humans. The 2003 message consisted of    12 images.

TEEN-AGE MESSAGE (2001)

Composed by Russian teenagers, this was transmitted from Evpatoria to the    Sun-like star HD 197976 in the constellation of Delphinus. The two-hour    transmission, in three parts, included 15 minutes of music played on a    theremin.