Hubble Space Telescope
Hubble Space Telescope
The forty-three and a half foot long, twelve ton, one and a half billion dollar Hubble Space Telescope was launched into orbit on April 24,1990 (Macchetto, p. 125). The Hubble Space Telescope or HST has been the best way to look far into the universe ever since then. Ground-based telescopes will never be able to see clearly into the universe, because the atmospheric turbulence scatters light (NASA, p. 6).
When the Hubble Space Telescope was launched it was poised to open a new era in astronomy. Within a few months, however, a flaw was discovered in Hubble's main mirror that significantly reduced the telescope's ability to focus. Program and project officials developed a plan to take advantage of the Telescope's instruments that were not affected by the flaw, such as, ultraviolet and spectrographic observations. Eventually it was found that the problem could be resolved by using the effect of computer processing to remove spherical aberrations (NASA, p. 5).
By using computer processing, the HST was still able to perform two of its three capabilities, including high angular resolution and ultraviolet performance. It did not have the capability of high sensitivity to detect very faint objects, because too much light is scattered and computer processing did not improve image quality (NASA. p. 10). Images of objects such as stars, planets and galaxies were blurred. On relatively bright objects, Hubble's cameras were still able to provide images far superior to any telescope on the ground. However, the high sensitivity problem was fixed by the first shuttle mission to the telescope in 1993.
Even during its first three years of operation, Hubble provided significant new information and discoveries about the universe, including astonishing images of Supernova 1987A and a disk of cold gas fueling a black hole (Smith, pp. 28-34). The images of space have had an important impact on the world, because it has spurred interest in science and solved many mysteries of the universe. The HST has already inspected more than 25,000 astronomical targets (http://hubble.nasa.gov/overview/). Many of these targets have either proved theories or shaped brand new discoveries about space.
One view tested by the HST was the distance between objects in space. Whether they are between stars or planets, distances in space can be deceptive and have only been estimates before (Macchetto, p. 129). In 1929, Edwin Hubble discovered that galaxies get redder, because they are moving away from or Milky Way Galaxy. Hubbles Constant is the term used to describe the distance scale of the universe (Smith, pp. 28-34). In May 1999 a Hubble project team finally decided on the correct Hubbles Constant after measuring distances between different galaxies. They arrived at a figure of seventy kilometer per second per megaparsec (http://hubble.stsci.edu/discoveries/10th/our_universe/in-depth/science.shtml/). This is much less than Hubbles original determined constant (Smith, pp. 28-34). The final determination of this constant would been impossible without the HSTs resolution and depth. This project will have a great deal of importance if the space program was to send space crafts deeper into unexplored space.
An unexpected and extraordinary use of the HST was to photograph pictures of the Shoemaker-Levy 9 Comet as it smashed into Jupiter in July 1994 (Ibid.). The twenty-one collisions with Jupiter produced large plumes of dust and debris, which could be seen perfectly with the Telescope. It also tracked the subsequent dust clouds from the impact areas (http://hubble.stsci.edu/discoveries/10th/our_universe/in-depth/science.shtml). The largest of these impacts created a crater as big as the Earth (http://hubble.stsci.edu/discoveries/10th/our_universe/in-depth/planet.shtml)! The images of the Comet hitting Jupiter were probably the most beneficial HST produced images as far as public support goes. The success of Hubble to capture these images brought back some public enthusiasm for the space program and also spawned movies, such as, Deep Impact. It helped to erase the memory of the mirror problem from many people.
The HST has also been used to confirm the existence of black holes, which form the centers of galaxies. Black holes cannot be seen directly though, because they eat up light as well as all other space elements. They can be seen indirectly by observing the space around the hole, because planets and stars will move faster as they begin to be pulled toward the black hole (http://hubble.stsci.edu/discoveries/10th/our_universe/overview3.shtml). The first confirmation of a black hole was from the HST. It first found a spiral disk of gas swirling around the giant elliptical galaxy M87. By using Hubble's spectrographs, astronomers could tell the speed that the disk of gas was swirling, and astronomers could then tell how much mass the black hole had (http://hubble.stsci.edu/discoveries/10th/our_universe/in-depth/blackholes.shtml). They calculated that more than 2 billion solar masses in a region no more than 120 light-years across were present in the supermassive black hole (Smith, pp. 28-34).
In early conferences concerning the usage of the HST, scientists agreed that it should be used to inspect star formations (Smith, pp. 28-34). HST has been looking at Supernova 1987A for quite some time, since it is the closest exploding star we have been able to witness (http://hubble.stsci.edu/discoveries/10th/our_universe/overview3.shtml). The star actually exploded first in 1987, but Hubble is able to see the explosion much better than the ground telescopes could. The HST has found that while the star explodes from within, many gases escape to create fantastic rings. The HST has been able to prove that the demise of stars is a more complicated process than originally thought (http://hubble.stsci.edu/discoveries/10th/our_universe/in-depth/stars.shtml). The telescope can continue to watch the supernova produce more light for years to come. Scientists hope that these images will help them to better predict a stars behavior.
The Hubble Space Telescope is a very important tool for research. The HST has continually surprised us all with its observations of comets, planets, black holes, and stars. We also now know the distances between objects in space. The fantastic images it has brought to the world has done a lot for the space program and educational community. The research of our universe is very important, and will help us to advance our knowledge of our world and make future discoveries.
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