Bad Astronomy: Misconceptions and Misuses Revealed, from ...

224 BEAM ME UP
I doubt Spitzer was thinking of Superman when he first proposed
a space telescope, but the idea’s the same. If you can loft a
telescope up, up, and away, out of the atmosphere, all those atmospheric
problems disappear. The ultraviolet and other flavors of
light that cannot penetrate our atmosphere are easily seen when
you’re above it. If the air is below instead of above you it won’t
make stars twinkle, and the faint objects will appear brighter without
the air glowing all around them, too.
Spitzer’s vision became reality many times over. Dozens of telescopes
have been launched into the Earth’s orbit and beyond, but
by far the most famous is the Hubble Space Telescope (colloquially
called HST or just Hubble by astronomers). At an estimated total
cost of $6 billion, Hubble has made headlines over and over again.
Its images have made millions gasp in awe, and the astronomers
who use HST have learned more from it than perhaps any other
telescope in history, except, just maybe, Galileo’s.
If you ask a random person in the street to name a telescope,
Hubble is almost certainly the only one he or she will know. However,
sometimes the price of fame is misconception in the public
eye. Ask anything more specific, and that person will probably falter.
Not many people know how big it is, where it is in space, or
even why it’s in orbit. Some think it’s the biggest telescope in the
world (or, more technically, above the world), some think it actually
travels to the objects it observes, and others think it is hiding
secrets from the public.
At this point in the book you’ve figured out on your own that
none of these statements is true. Let’s see why.
IT’S DONE WITH MIRRORS
Even the most basic aspects of the Hubble telescope are misunderstood.
For example, CNN’s web site, when describing one particular
Hubble observation, had a headline that read, “Stars Burst into
Life before Hubble’s Lens.” Actually, Hubble doesn’t have a lens.
Like most big telescopes, Hubble has a mirror that gathers and
focuses light. No less a luminary than Isaac Newton first figured
out that a mirror can be used instead of a lens, and the most basic