Transcript The Hubble Space Telescope (HST)

The Hubble Space Telescope
(H.S.T.)
By Jason Hunyar
The Beginning
• In 1923. The idea of a telescope in space, or at least outside Earth’s
atmosphere was proposed officially by a man named Hermann Oberth.
• A man named Lyman Spitzer Jr. helped encourage NASA to approve the
Large Space Telescope project in 1969.
• In 1974, the group working on the project suggested that the telescope
should have interchangeable instruments. The Space Shuttle would be
used to get the telescope in orbit and possibly return it to Earth for
repairs and replacement instruments, or they would just service it in
space.
• In 1975, the European Space Agency began to work together with NASA
on a plan that would eventually become the Hubble Space Telescope.
• In 1977, Congress approved funding for the telescope.
Why?
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The Hubble Space Telescope is the direct solution to a problem that telescopes
have faced since the very earliest days of their invention: the atmosphere. There
are two problems. The first problem that ground telescopes face are shifting air
pockets in the Earth's atmosphere. They make the the view of telescopes on the
ground blurry and distorted, no matter how large or scientifically advanced those
telescopes are. The second problem ground telescopes encounter is that the
atmosphere also partially blocks or absorbs certain wavelengths of radiation, like
ultraviolet, gamma and X-rays, before they can reach Earth. This is not good for
astronomers because scientists can best examine an object like a star by studying
it in all the types of wavelengths that it emits. Newer ground-based telescopes are
using technological advances to try to correct atmospheric distortion, but there's
no way to see the wavelengths the atmosphere prevents from even reaching the
planet.
The most effective way to avoid the problems of the atmosphere is to place your
telescope beyond it. Or, in Hubble's case, 353 miles (569 km) above the surface of
Earth.
*Cool Fact: This "atmospheric distortion" is the reason that the stars seem to
twinkle when you look up at the sky.
The On-Board Tools
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The Wide Field Camera 3 (WFC3) sees three different kinds of light: nearultraviolet, visible and near-infrared, though not simultaneously. Its resolution
and field of view are much greater than that of Hubble's other instruments.
WFC3 is one of Hubble's two newest instruments, and will be used to study dark
energy and dark matter, the formation of individual stars and the discovery of
extremely remote galaxies previously beyond Hubble's vision.
The Cosmic Origins Spectrograph (COS), Hubble's other new instrument, is a
spectrograph that sees only in ultraviolet light. Spectrographs acts something
like prisms, separating light from the cosmos into its component colors. This
provides a wavelength "fingerprint" of the object being observed, which tells us
about its temperature, chemical composition, density, and motion. COS will
improve Hubble's ultraviolet sensitivity at least 10 times, and up to 70 times
when observing extremely faint objects.
The Advanced Camera for Surveys (ACS) sees visible light, and is designed to
study some of the earliest activity in the universe. ACS helps map the
distribution of dark matter, detects the most distant objects in the universe,
searches for massive planets, and studies the evolution of clusters of galaxies.
ACS partially stopped working in 2007 due to an electrical short, but was
repaired during Servicing Mission 4 in May 2009.
The On-Board Tools (2)
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The Space Telescope Imaging Spectrograph (STIS) is a spectrograph that sees
ultraviolet, visible and near-infrared light, and is known for its ability to hunt
black holes. While COS works best with small sources of light, such as stars or
quasars, STIS can map out larger objects like galaxies. STIS stopped working
due to a technical failure on August 3, 2004, but was also repaired during
Servicing Mission 4.
The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is
Hubble's heat sensor. Its sensitivity to infrared light — perceived by humans as
heat — lets it observe objects hidden by interstellar dust, like stellar birth sites,
and gaze into deepest space.
Finally, the Fine Guidance Sensors (FGS) are devices that lock onto "guide stars"
and keep Hubble pointed in the right direction. They can be used to precisely
measure the distance between stars, and their relative motions.
All of Hubble's functions are powered by sunlight. Hubble sports solar arrays
that convert sunlight directly into electricity. Some of that electricity is stored in
batteries that keep the telescope running when it's in Earth's shadow, blocked
from the Sun's rays.
Where
Most people think of where the actual
telescope is in space when they think
of the HST, but the real information is
on the ground. The Goddard Space
Flight Center in Greenbelt, MD, is the
true base of the Hubble Space
Telescope. This is where the images
from the telescope itself are relayed
down from multiple satellites to (as
shown in the diagram). As soon as the
Goddard Space Flight Center receives
data from the telescope, they send it
to Space Telescope Science Institute
(STScI) where the staff translate the
data into meaningful units. Then the
data goes into archives and is enabled
to be downloaded by astronomers
anywhere in the world. The HST
usually brings in about 18 DVDs
worth of information every week.
Non-Visible Light
(Why this is important to us)
• Using the advanced instrumentation of the Hubble Space Telescope,
astronomers have been able to see different types of light, such as ultra
violet, that come through space dust, to find out more about the
universe. After analyzing these images through the COS, we have been
able to find out the composition of stars, galaxies, etc.
• But while the Hubble Space Telescope looks out through space, it is
also looking through time. As the telescopes looks at light that was
created x number of light years away, it can see what happened at that
place x number of light years ago.
• For example, if the HST was looking at the light of a star 30,000 light
years away, it would be looking at the same light that was created at
that star 30,000 light years ago.
Why we should care
As students and citizens, everyone around the world should care about the
Hubble Space Telescope. This telescope can unlock answers about
science that today, is beyond our wildest imaginations. This telescope
and future telescopes, should be able to help us find out huge questions
in the minds of scientists today; what happened at the beginning of the
universe. With all of these new discoveries, we will definitely by able
to make huge advances in science technology and future advances in
the world of astronomy.
As Neil Armstrong once said,
“That one small step for man, one giant leap for mankind.”
Source Citations
• http://hubblesite.org/the_telescope/hubble_essentials/