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The Hubble Space Telescope Is Back - Better Than Ever! Final Servicing Mission.
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The Hubble Space Telescope (HST) is a space telescope that was carried into orbit by the space shuttle in April 1990. It is named after the American astronomer Edwin Hubble. Although not the first space telescope, the Hubble is one of the largest and most versatile, and is well-known as both a vital research tool and a public relations boon for astronomy.
The HST is a collaboration between NASA and the European Space Agency, and is one of NASA's Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope.
Space telescopes were proposed as early as 1923. The Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, scientists found that the main mirror had been ground incorrectly, severely compromising the telescope's capabilities.
However, after a servicing mission in 1993, the telescope was restored to its intended quality. Hubble's orbit outside the distortion of Earth's atmosphere allows it to take extremely sharp images with almost no background light. Hubble's Ultra Deep Field image, for instance, is the most detailed visible-light image ever made of the universe's most distant objects. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.
The Hubble is the only telescope ever designed to be serviced in space by astronauts. There have been five servicing missions, the last occurring in May 2009. Servicing Mission 1 took place in December 1993 when Hubble's imaging flaw was corrected. Servicing missions 2, 3A, and 3B repaired various sub-systems and replaced many of the observing instruments with more modern and capable versions.
However, following the 2003 Space Shuttle Columbia accident, the fifth servicing mission was canceled on safety grounds. After spirited public discussion, NASA reconsidered this decision, and administrator Mike Griffin approved one final Hubble servicing mission. STS-125 was launched in May 2009, and installed two new instruments and made numerous repairs.
The latest servicing should allow the telescope to function until at least 2014, when its successor, the James Webb Space Telescope (JWST), is due to be launched. The JWST will be far superior to Hubble for many astronomical research programs, but will only observe in infrared, so it will complement (not replace) Hubble's ability to observe in the visible and ultraviolet parts of the spectrum.
About the Lecture
Perhaps the universe is not so much strange as brimming with lovely paradox. The search for such beauty seems to lie at the heart of Frank Wilczek’s work. Twentieth century physics, from Einstein through Wilczek’s own Nobel Prize-winning efforts, involves demonstrating the existence of a topsy-turvy reality: for instance, that such sub-atomic particles as quarks and gluons, which have little or no mass, “orchestrate themselves into not just protons and neutrons but you and me,” according to Wilczek. “How is it possible to construct heavy objects out of objects that weigh nothing?,” he asks. Only by “creating mass out of pure energy.” These particles are essentially “excitations in otherwise empty space.” Says Wilczek: “That suggests something …beautiful and poetic: the masses of particles are not like, or similar to or metaphorically suggested by—they are the tones or frequencies of vibration patterns in dynamical voids.” The theory of quarks and gluons and the strong interaction accounts quantitatively for “the mass of protons, neutrons and ultimately you and me and everything around us.” But physics has not yet squared away all aspects of the universe. Wilzcek says that “in cosmology, we meet our match, and don’t know what’s going on.” This is because scientists can’t account for much of the mass in the cosmos. 70% of this mass is in “dark energy,” which is pushing the universe apart. Wilczek hopes that explanations for the dark stuff will emerge through improving equations, unifying theories of different interactions and extending their symmetries. “Beautifying equations leads not to ugly consequences but beautiful surprises,” he concludes.