Where and How Do We Look?
Now that we've decided that it's worth looking, where and
how do we look? We have to agree on the method. Several come to mind.
First, our alien friends could travel in a space ship and
visit us. That would be a great method of communication -- face to face.
Unfortunately, despite all the alleged Roswells and alien abductions and
UFO sightings, there is not a single shred of scientific evidence that aliens
have ever visited the earth. Not one. The amount of energy and time necessary
to travel between the stars is so immense that a more "economical"
method is mandated. Doing some simple calculations, you can prove that even
if someone could invent a ship with the most efficient type of engine ("Star
Trek" fans will be happy to know that this involves matter and antimatter!)
that a trip to the nearest star, Alpha Centauri, with a twenty-year round-trip
travel time would use enough energy to power over a million houses for over
thirty million years! And this trip would only take a few people as passengers!
This is not an economical method to communicate because this amount of energy,
at today's costs, would cost well over $30 quadrillion. Can you imagine
any alien government allocating this kind of resource to send a few of their
people for a friendly visit? Of course, they could send out thousands or
millions of lightweight probes announcing their existence and the probes
could report back their findings, but this would still be very costly in
both time and energy. Even though we would like to believe in warp drive,
interdimensional shifting, and all the other wonders of science fiction,
they are just that, fiction.
It seems unlikely that alien civilizations will foot the $30 quadrillion
dollars in today's energy costs to visit us in person. Contact via radio
signals is more economical. The photograph on the right is yet another UFO
|How would you contact a friend or relative living in a far
distant country if all you wanted to say was "hello!" Would you
go there? Probably not. You would simply pick up the phone and make a call,
or you might send an email, or if you have the right equipment, you might
even strike up a video teleconference. All of these methods are vastly more
economical and timely than traveling by jet. Likewise, any advanced civilization
would probably choose to communicate via "economical" methods.|
|The best method that we know of is to communicate by radio
waves. Transmitting information over radio waves is very cheap, uses equipment
that is easy to build, and has the information-carrying capacity necessary
for the task. The information also travels at the fastest speed in the universe,
the speed of light. No space ship can ever match this speed. Furthermore,
if you are using a radio transmitter, you can point it in millions of directions
and communicate simultaneously with many different civilizations. Can't
do that with a ship! Look at all the ways you use radio transmissions: radio
and TV, of course, cellular phones, pagers, all satellite communication,
GPS navigation, and much more. On earth, we've already decided on the most
|So if we are going to look for aliens trying to contact us
by radio waves, we have another problem on our hands. When you turn on your
radio, you have to decide what frequency, or channel, you are goung to listen
to. You can tune through the various radio bands -- AM, FM, short-wave,
ham, police, weather, etc. -- to find your desired program. Likewise, we
will have to tune our extraterrestrial ear to find our alien friends. The
electromagnetic spectrum is a very, very large place and there are some
phenomena that we should examine that might make our tuning decision easier.
It would be nice, at least, to find a reasonably small region of the electromagnetic
spectrum in which to start our search.|