The Hubble Space Telescope
Astronomy Got a Shot in the Arm with the Exciting Images of Hubble
Aug 31, 2009
Perhaps no other telescope in history has reached the public imagination as The Hubble Space telescope. Launched in 1990, it immediately caught the public’s attention. At first it was not because its images were fantastic, indeed they weren’t, they were awful. There was a distortion in one of the mirrors and it made the light acquisition look, well “nearsighted.” It was a very tiny flaw, about 1/50th the thickness of a sheet of paper. But after it was fixed, its images lived up to and exceeded expectations. Everything that the Hubble scope peered at looked magnificent.
The Telescope is named after the famed astronomer of the early to mid 20th Century, Edwin Hubble. His scientific observations changed the way astronomers, physicists and other scientists and the public in general looked at the cosmos, in a way that had not been done since Galileo, Kepler, and Copernicus. In a series of spectacular images, Hubble was able to peer back almost 13 billion light years, close to the time of the big bang.
The Telescope as Time Machine
Unlike other scientific instruments, a telescope in general, one that peers into the heavens, is not looking at light as it is now, but rather as is was when the light was emitted from a star.
Consider the following. The Sun is located about 8 minutes from earth, if you travel at the speed of light. That is the distance from the Sun to the Earth, about 93 million miles, can be traversed in eight minutes if you are traveling at light speed. So imagine the following. Suppose the Sun went Supernova right now. What would happen on Earth, right now? Nothing.
Surprised? How can that be, wouldn’t the Sun’s explosion destroy the earth? Yes, but not for another 8 minutes. The Supernova explosion cannot travel faster than the speed of light. So on Earth everything would appear normal for eight minutes. Then boom!
But that is just an eight minute scenario. Telescopes peer at objects located hundreds, thousands, or even millions of light years away. That means that the light that they perceive is hundreds, or thousands, or millions of years old. So the telescope is looking at the past. It is a time machine.
The Hubble space telescope is one of four orbiting telescopes that NASA put into space in the Great Observatories Program. These four telescopes were designed to gather different forms of electro-magnetic energy. Hubble, visible light. Chandra X-ray. Compton Gamma-Ray. And Spitzer Infra-Red. NASA wanted to study the stars and galaxies using different wavelengths of the electro-magnetic spectrum. The same object would give off different features that could not be captured by light alone.
It takes Hubble 97 minutes to complete a rotation around the Earth. It has a small mirror, only about 94.5 inches (2.4 meters) in diameter. Small when compared to some ground based telescopes that have diameters approaching 400 inches. The main feature of Hubble is the location in space, so images cannot be distorted by the atmosphere.
The End of Hubble
Advances in telescopy have made Hubble’s space location unnecessary. Ground based telescopes, like the Large Binocular Telescopein Arizona, with their computer interferometers have made it possible to duplicate and even exceed the clarity of the Hubble images. Hubble was last serviced in May 2009, and it is currently slated to be decommissioned in 2013.
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