Dr.
Robert Agnew
(shown above sitting atop an ancient Mayan observatory in Mexico)
is a Professor of
Music and Humanities at Edison State College in Piqua,
Ohio.
Born in Youngstown,
Ohio,
Robert has a
Masters Degree from Bowling
Green
State
University
and a Ph.D. from Michigan
State
University.
Ancient
Rocks
In
science fiction movies or
television shows dealing with outer space flight, it seems as if the
space
voyagers are occasionally battling asteroids. When they encounter the
asteroids, there are a phenomenal amount of them cluttering space,
filling the
movie or television screen with a plethora of giant rocks, ready to
destroy the
spacecrafts unless the pilots are unusually gifted (and they usually
are).
The
reality is that there are,
indeed, an extraordinary amount of asteroids, but most of them are
spread out
in a very distant orbit of our solar system known as the Main Belt.
Space, as
we know, is mind numbingly big and is occupied, mostly, by nothing. In
fact,
encountering an asteroid in a voyage from Earth to a moon of Jupiter
(where one
would cross the Main Belt) would be most unlikely.
Imagine
taking a thousand marbles
and spreading them around the United Kingdom, a few tossed out in
London,
Liverpool, Manchester, York, Sheffield, Cambridge, Edinburgh, Glasgow,
Belfast
and other cities as well as throughout the beautiful British
countryside (you
might want to put at least one marble at Stonehenge). If you then asked
someone
who had no idea where you put the marbles to gather them up for you,
their
reaction would give you a better feel for why asteroids do not
represent a
danger to space travelers, and of the enormity of the distances between
the
asteroids.
In
the 18th century there was an
exciting search for the missing planet that was predicted to be between
Mars
and Jupiter. Many countries and their respective astronomers were
hoping to
capture the great distinction of making the grand discovery. When the
asteroid
Ceres was discovered on January 1st, 1801 by the Italian astronomer
Giuseppe
Piazzi, it created quite a sensation, not least because it proved too
small to
be a planet. This new celestial body was slightly less than 1000
kilometers
(600 miles) in diameter - much too small of a diameter to be considered
a
planet. For a while it was believed that a large planet had broken up
to
produce the asteroids - though we now know that all the asteroids put
together
would not have enough mass for a single planet. Since the discovery of
Ceres,
astronomers have identified over 350,000 asteroids, though only about
twenty
asteroids are more than 250 kilometers (150 miles) in diameter.
Unknown
to many amateur astronomers
is the fact that quite a number of asteroids can be observed with only
a modest
telescope, and the asteroid Vesta can occasionally be seen with the
naked eye.
A four inch telescope enables an amateur astronomer to observe several
hundred
asteroids. A dozen or so asteroids can be observed with binoculars. But
perhaps
the most interesting aspect of observing an asteroid is that you can
notice its
movement in a single night.
In my
astronomical journal of April,
17, 2004, I
note: “The star has moved - Ceres is found!” I was
responding to the fact that
the asteroid, which I had presumed to observe the night of April
16, 2004,
had moved in position when observed on the night of April 17th. Since
then I
have observed 123 asteroids, each one carefully plotted so I could
determine if
it had indeed moved. Most of those determinations were made on the same
evening, giving a separation of five or six hours between observations.
The
magnification needs to be fairly high, but it is indeed a delight to
realize
that the little star-like asteroid (the name asteroid means
“star-like”) has
shifted its position among the stars.
If
you’ve got a telescope or a good
pair of binoculars and you want to locate an asteroid, what do you do?
If you
expect to be a committed amateur astronomer, there are several computer
programs which keep track of the movements of the asteroids as well as
galaxies, planets, clusters, and just about anything that’s
out there that can
be seen with a telescope. You can also get information from several WEB
pages
dedicated to asteroid observation. Your local astronomy club or
planetarium is
a good place to start your search for the fascinating, ancient rocks of
our
solar system. .
©
Article &
image Dr. Robert Agnew 2008/2009