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In the Beginning ...
Since the dawn of civilization, man was limited by his vision and
imagination about his understanding of the universe. The telescope
enhanced his vision and tempered his pride, as observations by Copernicus,
Galileo (see image on left), and Kepler
in the 16th and 17th centuries A.D. rebuffed the millennia-old conceit
that the Earth is the center of the universe, spearheading the Scientific
Revolution.
By the 18th century, the telescope would become the indispensable
instrument for investigations of the cosmos. Bigger and better telescopes
were built all over the world. Planets, stars, and nebulae which could
not be seen by the naked eye were now being routinely noted and logged.
Advances in spectroscopy, photography, and photometry increased telescope
versatility, sensitivity, and discovery power.
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Enter Edwin Hubble
By the turn of the 20th century, most astronomers believed that the
observable universe consisted of one galaxy, our Milky Way Galaxy,
an oasis of stars, dust, and gas in the vastness of space. However,
in 1924, American astronomer Edwin Hubble used the 100-inch Hooker
Telescope (see image on left) on Mount
Wilson near Los Angeles, California, to observe billions of other
galaxies besides our own Milky Way, almost all moving away from each
other. This suggested that the universe is expanding, unleashing a
Pandora's box of seminal inquiries—such as the Big Bang theory—about
the possible beginning and end of the universe—issues which
are still being debated to this day.
Astronomers like Edwin Hubble (before and after his time), toiled
long, frigid nights inside enormous dome-shaped "observatories"
pointing their telescopes skyward, yearning for the best possible
snapshot of the heavens. However they faced a major obstacle that
stood between them and a clear view of the universe: the Earth's atmosphere.
The Earth's atmosphere is a fluid, chaotic soup of gas and dust.
It blurs visible light, causing stars to twinkle and making it difficult
to see faint stars. It hinders or even totally absorbs other wavelengths
of light, making observations of such wavelength ranges as infrared,
ultraviolet, gamma rays and X-rays difficult or virtually impossible
(it is also these properties which protect us from the harmful effect
of these rays).
Observatories with the largest of telescopes in various continents
have been perched upon mountain tops and away from distracting city
lights, from Caucasus Mountains in Europe to the Australian outback,
with varying levels of success. Adaptive optics and other image processing
techniques have minimized—but not totally eliminated—the
effects of the atmosphere.
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