Hubble is one of the most important tools in discovering other galaxies.
The Hubble Telescope is one of the most important innovations in space technology. It allows us to see stars and galaxies across the universe that normally would not be accessible. Hubble has uncovered important information that has helped settle debates about the history of the universe.
History
The National Academy of Sciences had originally recommended a large space telescope in 1962. As far back as 1946, Lyman Spitzer had been exploring the idea and in 1965 was appointed to head a committee with the intent to define the scientific objectives of the telescope. Congress agreed to fund the project in 1977 and construction was completed in 1985, but the space shuttle Challenger explosion the following year set back its launch. The telescope was finally launched on April 25, 1990.
Name
In 1983 the telescope was officially named after Edwin Hubble, an American astronomer who profoundly changed the world's understanding of the universe by demonstrating the existence of other galaxies beyond the Milky Way. In 1929 he formulated Hubble's laws, which describe physical characteristics of the universe and the velocity at which galaxies move in an expanding universe. This supported the Big Bang model and Einstein's theory of general relativity.
Flaws
When the telescope was initially launched in 1990, NASA soon discovered that Hubble had a flawed mirror. The telescope took pictures that were clearer than they would have been from the Earth, since the atmosphere distorts the clarity of images, but it had not achieved the sharpness of its peak focus. NASA soon discovered that the edges of its mirror were too flat by 2.2 micrometers (a millionth of a meter). In 1993, astronauts placed corrective optical components in the telescope to counteract the problem.
Upgrades
Since its original launch, most of the optical components in the Hubble Telescope have been upgraded or replaced. There have been five separate space shuttle missions to do so, including the first that corrected the original optical flaw.
Importance
Hubble has helped resolve some important problems such as the rate of universal expansion---namely the fact that it is accelerating---the age of the universe, extrasolar planets and the existence of super massive black holes in the center of galaxies. It also captured images of a comet impacting Jupiter and small areas of the sky that contain billions of galaxies.
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