The Decade of Discovery in Astronomy and Astrophysics (1991) / Chapter Skim
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Appendix A: Glossary
Appendix A: Glossary
Pages 137-149
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Adaptive optics A set of techniques to adjust the mirrors of telescopes on time scales of hundredths of a second to correct for distortions in astronomical images due to turbulence in the earth's atmosphere. Airshower detector Highly energetic gamma rays collide with atoms and molecules in the earth's upper atmosphere and produce bursts of light and particles, called airshowers, that can be detected from the ground, giving information about the most energetic processes in the universe.
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Brown dwarf A star-like object that contains less than about 0.08 the mass of the sun and is thus too small to ignite nuclear fuels and become a normal star. Brown dwarfs emit small amounts of infrared radiation due to the
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correspond to radio radiation, intermediate wavelengths to millimeter and infrared radiation, short wavelengths (high frequencies) to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
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. Infrared astronomy The study of astronomical objects using intermediate-wavelength radiation to which the atmosphere is mostly opaque and the human eye insensitive.
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Fainter stars have numerically larger magnitudes. The brightest stars, excluding the sun, are about magnitude 0; the faintest star visible to the unaided eye is about magnitude 6.
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Radio astronomy The study of astronomical objects using radio waves with wavelengths generally longer than 0.5 to 1 mm. See electromagnetic spectrum.
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Supernova A star that, due to accretion of matter from a companion star or exhaustion of its own fuel supply, can no longer support itself against its own weight and collapses, throwing off its outer layers in a burst of energy that outshines an entire galaxy. In 1987 a star in the Large Magellanic Cloud was observed as a dramatic supernova called Supernova 1987A.
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A NASA mission launched in 1989 to study the cosmic background radiation from the Big Bang.
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IRTF The Infrared Telescope Facility. A 3-m telescope located on Mauna Kea, Hawaii, and operated by NASA to study planets and other astronomical objects.
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SIRTF—The Space Infrared Telescope Facility. NASA's fourth Great Observatory will study infrared radiation.
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The main imaging instrument on the Hubble Space Telescope. A modified version will be installed in 1993 to correct for distortions in the HST mirror.
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