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

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Hubble Trouble: Hubble Space
Telescope Misconceptions
I n
1946 astronomer Lyman Spitzer had a fairly silly idea: take
a big telescope and put it in space. Looking back on his idea
more than half a century later, it doesn’t seem so crazy. After all,
various nations have spent billions of dollars on telescopes in space,
so someone must be taking the idea seriously. But in 1946 World
War II was barely a year in the history books and the first launch
of a satellite into orbit was still more than 10 years away.
Spitzer was a visionary. He knew that a telescope in space would
have huge advantages over one on the ground, even before the first
suborbital rocket flight gave others the idea that it was even possible.
Sitting at the bottom of our soupy atmosphere yields a host of
troubles for ground-based telescopes. The atmosphere is murky,
dimming faint objects. It’s turbulent, shaking the images of stars
and galaxies until they all look like one blurry disk. Perhaps worst
of all, our air is greedy and devours certain types of light. Some
ultraviolet light from celestial objects can penetrate our atmosphere
(the ultraviolet from the Sun is what gives us tans, or worse), but
most of it gets absorbed on the way in. The same goes for infrared
light, gamma rays, and x-rays. Superman may have x-ray vision,
but even he couldn’t see a bursting neutron star emit x-rays unless
he flew up beyond the atmosphere, where there is no air to stop
those energetic little photons.
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