Last
week I mentioned that I hate screen savers but when I do use one, I use the
SETI screen saver. I had numerous emails about the SETI project and several
people told me that they too are now involved in the SETI. SETI stands for
"Search for extraterrestrial intelligence." If you've followed this
column for any length of time, you probably already know that astronomy is one
of my main hobbies. Instead of answering these emails individually, I thought I
might just devote a column to the SETI project and astronomy on the Internet.
When
you are using the SETI screen saver, what you are doing is analyzing data
collected by the 300 foot
The
distances between us and the other stars in our galaxy are enormous. Traveling
at the speed of light (186,000 miles a second) it takes a radio signal over
100,000 years just to travel from one end of the Milky Way galaxy to the other.
Our Sun is located in the outer region of one of the spiral arms of the Milky
Way. If you get away from the city lights and look up at the sky on a
clear dark night, you'll see a hazy patch of light running across the sky. It
almost looks like a cloud. What you're seeing is part of one of the pinwheel
arms or our galaxy. If you were to look at this "cloud" through
a telescope, you'd see that it’s really made up of millions of stars. In our
own galaxy, there are over a million million stars.
And there are millions of millions of galaxies in the universe. Some scientists
speculate that there may even be countless numbers of universes.
In
space, distance and time are relative. When you look at the sun, you are seeing
it as it looked about 7.5 minutes ago. It has taken that long for
its light to reach us. When you look at the sky, you’re looking into
the past. The Hubble telescope can capture light that has been traveling
through space for billions of years. This is a strange concept to most of us.
Compared to astronomical time, we live such short lives that it's hard to
imagine billions of years. Many of the stars in the nighttime
sky haven't existed for hundreds of thousands of years; yet, we'll
continue to view them as if nothing has happened.
Here's
an example to help clarify that statement. Have you ever heard a jet plane and
looked up only to find that the plane is far ahead of its sound? It's
the same principle as starlight only on a much slower scale. Sound travels
about 750 miles an hour. By the time the plane’s sound reaches you, the plane
will have moved many miles from where the sound is coming from. Another
example is lightning. When you see a flash of lightning,
count the seconds until you hear the thunder. Each second between the
flash and the thunder is about .2 of a mile. If 5 seconds passes before you
hear the thunder, the lightning was about 1 mile away.
So,
where is ET and his friends? Unfortunately, even if
there are millions of civilizations all around us, the chances
that we will be able to pull their signals out of the galactic noise is
remote. SETI is searching a small section of the electromagnetic
spectrum but there are many other ways to communicate. We only discovered
radio waves ourselves in the 19th century, and we are already developing
newer forms of communications (laser, microwave etc.). In the next hundred
years, we may abandon radio as a form of communication altogether. Who knows
what medium is yet to be discovered?
The
point is, if we quit searching, we’ll never find anyone. Anybody with a
computer and an Internet connection can join in the search. The odds may be
staggering, but to actually find out that we are not alone in the universe
would be one of the greatest achievements imaginable.
Here
are some sites to visit if you want to know more about SETI or astronomy in
general. www.seti.org/teamseti.html,
http://mc.harvard.edu/seti/, http://www.nasa.gov/,
These three sites have links to additional astronomy
websites. The Internet gives everyone access to the world’s finest
observatories and astronomical libraries. The heavens are just a click away.
Reach me at randy@randybenjamin.com