Telescopes were used to enhance
vision for better observations of our universe since the 16th and 17th
centuries. When the 18th century came around, the telescope was the
go-to instrument to explore the universe with just the naked eye. It allowed
people to observe such distant objects that would otherwise unseen by the naked
eye, this allowed for such huge advancements in this field of science. As the
20th century began, many astronomers believed that the universe only
consisted of one galaxy: the Milky Way. But, in 1924, an American astronomer,
Edwin Hubble, disputed this belief and believed that there were galaxies than
just our own. He used the Hooker telescope on Mount Wilson in California to
observe so many other galaxies that were all moving away from each other. This
observation triggered to raise a theory of how the universe was constantly
expanding. Many astronomers spent many nights in observatories using telescopes
to help prove this theory and possibly find out more unknown facts about the
universe, however, there was a major obstacle that prevented them from getting
a clear image of the universe: the Earth’s atmosphere.
The Earth’s atmosphere blurs visible
light, which causes brighter stars to twinkle, hence making it harder to
observe dimmer stars in comparison. In addition, the atmosphere absorbs or
totally blocks other wavelengths of light such as ultraviolent, infrared, gamma
rays, and X-rays (to actually protect us from the harmful effects of these
types of light rays). This is also why observatories have telescopes near the
tops of mountains to prevent any disruptions caused by city lights. In 1923,
Hermann Oberth (a German scientist), published a paper that proposed a
telescope being propelled into Earth’s orbit with the use of a rocket to bypass
the obstacle of the Earth’s atmosphere in observations. A Princeton
astrophysicist Lyman Spitzer then wrote about his support about the scientific
benefits of a telescope above the Earth’s atmosphere in 1946. Subsequently, as
the Soviets launched their satellite Sputnik in 1957, NASA followed suit and
launched two Orbital Astronomical Observatories (OAOs) into orbit. This allowed
for further research into more space observatories and allowed them to make
many ultraviolet observations.
As a result, in 1969 after Spitzer
gathered support of other astronomers, the National Academy of Sciences
approved a project for a Large Space Telescope (LST). Although, with the “race
to the moon” by the Soviets and the Americans, much of NASA space program
funding went into their expedition and landing on the moon in 1969, which put
the project for a LST in jeopardy. This caused numerous budget reductions into
the building of the LST but in 1974, the LST had specifications to have a
wavelength range from ultraviolet to infrared light and it had the ability to
resolve at least one-tenth of an arcsecond.
After finally building the LST, the
next issue was how NASA was going to launch it into space. NASA and its
partners began to think of something that could launch an object into orbit but
then return to Earth, in order to be reused over and over again, this resulted
in the concept of the space shuttle. NASA predicted that the lifetime of a
space telescope would be approximately fifteen years, which raised the issue of
having the ability to service the satellite while it is in orbit. They began to
develop tools and parts that were high quality but did not harm the satellite’s
orbit due to its size; too many instruments (especially large ones) decreased
any chances of financial support. NASA and the European Space Agency (ESA)
exchanged fifteen percent of telescope time for fifteen percent of the funding
for the LST. By 1977, Congress approved the funding and construction began.
NASA began to then assign tasks for
specific NASA field centres. First, the Marshall Space Flight Centre in
Huntsville, Alabama was chosen for the design, development, and construction
for the newly named Space Telescope (ST). Next, the Goddard Space Flight Centre
in Greenbelt, Maryland was chosen to be the lead in scientific instrument
design and ground control for the space observatory. Lastly, the Johnson Space
Centre in Houston, Texas and the Kennedy Space Centre in Florida provided Space
Shuttle support. Maintenance and any upgrades of the space telescope were
decided to be done while in orbit as opposed to on Earth to save funding and by
1985 the telescope was renamed the Hubble Space Telescope (HST) and was ready
for launch. Unfortunately, in 1986, an accident required NASA to ground the satellite
but the bright spot was the enhancements that were made to the equipment on the
satellite including the solar panels, computers, and communication systems.
Following many stress tests to improve durability, the HST was brought into
orbit on April 24, 1990 by the Space Shuttle Discovery.1
The Hubble Space Telescope has been
in orbit for more than twenty years now and with recent services done to the
telescope, it is predicted that the HST would last at least five more years.
The telescope has resulted in many discoveries that have greatly impacted the
field of science. Two discoveries it has made are dark matter and dark energy,
two new fields that have now many physicists exploring these new topics. Dark
matter makes up for about twenty-three percent of the universe and is only
known to exist based on gravity (it cannot be seen). Dark energy, on the other
hand, helped to observe that the rate of expansion by the universe is
accelerating as opposed to being constant or slowing down. In addition, the HST
has made many important advances in field of extrasolar planets by even having
the ability to determine the composition of their atmospheres.4 I
have chosen these three results because it is so fascinating that beyond our
world there many things that humans have not discovered and the way we perceive
our world and our universe can change at any second especially with the way
advancements in science seem to be trending upward at an astonishingly fast
rate.
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