Radio
We have artificially produced radio waves
for over one hundred years now, but the
universe was filled with radio emissions
long before that. Astronomers have been
able to make useful observations at radio
wavelengths for only 70 years or so.
Since radio waves are long in wavelength,
our radio telescopes must also be huge.
Microwaves
We are familiar with microwaves
because we use them to heat our
food. But microwave astronomical
observations will reveal relatively
cool objects in the universe, such as
interstellar dust.
Infrared
We sense infrared as heat.
Infrared has a wavelength slightly
longer than visible light. Some
predators, such as snakes, are
able to locate their prey by the
infrared radiation they emit.
Visible
Visible is what we see, of course.
Humans have also come to divide
visible light into what we call
colors. You are perhaps familiar
with Roy G. Biv.
Ultraviolet
U.V. radiation has a slightly
smaller wavelength than visible
light and therefor, slightly more
energy. That extra energy can
damage skins cells. Fortunately,
Earth’s ozone layer saves us. But
sunscreen is definitely a must!
X Rays
With short wavelengths and high
energies, X Rays can do a lot of
damage. They are generated in
this universe by objects that have
temperatures of millions of
degrees.
Gamma Rays
Gamma rays are the most
energetic of all electromagnetic
radiation. They are generated by
the massive explosions called
supernovae. In recent decades,
we have been puzzled by short
bursts of gamma rays in the sky.