Back to the
Ask An Astronomer page.
Hmm.. I think I just responded to one of your compatriots!
What's good about space telescopes is that they avoid the
atmosphere of the Earth. The earths atmosphere seriously
degrades celestial images. The telescopes are also free of
light pollution.
What's bad about space telescopes is the flip side of this -
because they are not on Earth, they have to be operated remotely.
This is a problem if something goes wrong. When I observe at a
telescope on Earth, there are always little glitches that come up.
The dome shutter gets jammed. A filter wheel gets stuck. I just
go out and fix the problem, or get help from a telescope technician.
But in space, if something goes wrong, you have to wait for a
shuttle mission to repair it. A more subtle problem is that
on Earth, as better detectors become available, it is easy to upgrade
the instruments. But in space, again, you need a shuttle mission to
upgrade the telescopes. Maintaining the Hubble Space Telescope has
become an important part of the shuttle program! And this is an
enormous expense! So putting telescopes in space is incredibly
expensive, and maintaining them is incredibly expensive.
Why do it? because the good points (get out of the destructive
presence of the Earths atmosphere) means that we can do science
that would otherwise be _impossible_. Not difficult, impossible!
We have learned more about the universe in the years that space
telescopes have been up (merely a few years) than in the centuries
that we have been gazing up to the sky and trying to understand
the smeared out images that we see!
Good luck with your studies.
-Debra Fischer
Back to the
Ask An Astronomer page.