There is no doubt about it, we have been invaded by aliens!
Actual alien beings have not traveled to our planet, of course,
but they have definitely become a part of our culture. Hollywood
has been an especially attractive place for aliens of all kinds.
Star Wars, Star Trek, Alien, Predator, Close Encounters, E.T.,
Men in Black, and (my personal favorite) Contact have given very
diverse answers to questions about whether life exists outside
our planet and, if so, what that life might be like. Almost
everyone has an opinion on this matter. Pick up a tabloid and
there is a good chance you will find a creative story about the
latest "alien" and human encounters. A psychic hotline will, for
a fee, connect you with life in other solar systems. When an
unusual light is seen in the night sky, the popular explanation
is a spaceship visiting from outer space. Is there a definite
answer to the question of life existing on other planets?
What Do Scientists Think?
Some scientists think that the universe must be teeming with
intelligent life. Other scientists think life is a very rare
occurrence. Still, most scientists agree that intelligent life
probably exists somewhere else in the universe. Science requires
strong evidence to support claims about our world, so the
question of extraterrestrial life is by no means settled.
Without hard evidence, though, why are so many scientists
convinced we may not be alone in the universe?
The answer has to do with the vastness of space. There are
millions of galaxies in the universe. Our own galaxy, Milky Way,
contains hundreds of billions of stars. We have strong evidence
that planets exist around other stars, and some scientists
believe solar systems are quite common. But even if only one
star in a million in the universe had orbiting planets, and only
one in a million of those planets were home to some form of
intelligent life, then even with this conservative estimate,
there would be a million other civilizations out there!
Can We Find Out For Sure?
The most promising way of discovering intelligent life elsewhere
is by detecting radio signals from technologically advanced
civilizations. Radio waves travel at the speed of light (186,000
miles per second) and are not easily absorbed or distorted by
cosmic dust in space. Those signals might be intentional
messages or "local" communications that we detect when the
signals inadvertently reach us (Our own TV transmissions of
fifty years ago are now over halfway to reaching a thousand
stars like the sun!). Will we detect any signals sent from
outside our solar system?
The Search Is On
Although searches for radio signals have been conducted by
various astronomers since 1959, most of these searches were
small in scale and short in duration. In 1992, NASA began a
comprehensive, extremely powerful scanning project called HRMS.
Within a year, though, the project lost its federal funding. The
SETI Institute (Search for Extra Terrestrial Intelligence)
provided private funding for the project which is now known as
Project Phoenix. So far, no artificial radio signals have been
detected, but only a small area has been searched.
What If We Find Life Out There?
The purpose of Project Phoenix and similar search projects is
simply to detect radio messages coming from outside the solar
system. An intentional message would most likely be sent in a
mathematical code (math is a universal language) and would
probably be fairly easy to interpret. The only way a distant
civilization would know their message had been received, though,
would be if we answered a signal by sending a response. If we
did find other life out there, should we try to communicate?
Much speculation has focused on whether other civilizations (if
they existed) would be friendly. There are some good arguments
for unfriendly aliens. A common biological argument is that in
nature it pays to be aggressive. Also, perhaps even civilized
aliens much more intelligent than we are would think no more
about destroying us than we would about swatting flies in our
kitchens. A more compelling argument, though, suggests we need
not fear other civilizations. If civilizations exist which are
more technologically advanced than ours, they most surely
figured out long ago a way to live peacefully and responsibly
with technological knowledge that could be used for massive
destruction. Otherwise, they would have already destroyed
Perhaps, though, instead of worrying about the potential
friendliness of another civilization, we ought to take a good
look at ourselves. What would other intelligent life think about
human beings? What impression would our civilization make? I
would be a little embarrassed to invite an extraterrestrial to
our world just yet. As one fictional being in Contact noted, we
are ". . . an interesting species, an interesting mix--capable
of beautiful dreams, and horrible nightmares." Still, if a
technologically advanced civilization has learned to survive for
millions of years, then surely we could benefit from its
experience. It does seem like we could use a little help right
Intelligent life might be found outside our solar system
within the next century. Or, maybe we are truly unique to the
universe and we will never detect another civilization. In any
case, through the search process we learn more about the world
around us. For now though, the question, "Is anybody out there?"
The next time you are outside on a clear night, pick a star and
instead of making a wish, ask yourself some questions. Might
that star have any planets orbiting it? If so, do any of those
planets have life? And if so, is there a being looking your
direction, pondering the same thing? There is no harm in a
2006 Dirk Oden