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The Transparency of the Earth's Atmosphere
Electromagnetic
radiation from space is unable to reach the surface of the Earth except at
a very few
wavelengths, such as the
visible spectrum
and radio
frequencies. Astronomers can get above enough of the Earth's atmosphere to
observe at some
infrared wavelengths from mountain tops or by flying their telescopes in
an aircraft. Experiments can also be taken up to altitudes as high as 35 km
by balloons which can operate for months. Rocket flights can take instruments
all the way above the Earth's atmosphere for just a few minutes before they
fall back to Earth, but a great many important first results in
astronomy and
astrophysics
came from just those few minutes of observations.
The best solution, however, is to get above it all. Here is a list of
observatories at all wavelengths currently or recently in space with links to
information about what each one is doing:
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