Gamma-ray bursts: upping the ante.Like cosmic flashbulbs, gamma-ray bursts gamma-ray burst n. A short-lived, localized, and intense burst of gamma radiation that originates outside the solar system from an unknown source. are intense flares that last just a few seconds and then vanish, usually forever. The origins and properties of these celestial bursts have remained a mystery since their discovery 20 years ago. Early results from NASA's Gamma Ray gamma ray Penetrating very short-wavelength electromagnetic radiation, similar to an X-ray but of higher energy, that is emitted spontaneously by some radioactive substances (see gamma decay; radioactivity). Observatory add a new twist to the puzzling phenomenon. Since the April 5 launch of this orbiting observatory, its detectors have recorded about one gamma-ray burst per day -- a rate higher than that detected by any other satellite, says Gerald J. Fishman of NASA's Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC), the original home of NASA, is a lead center for propulsion, Space Shuttle propulsion, Shuttle external fuel tank, crew training and payloads, International Space Station (ISS) design and construction, for computers, networks, and in Huntsville, Ala. Fishman explains that the eight detectors placed around the craft's perimeter, where they monitor bursts throughout the sky, form a larger collecting area and thus can detect fainter bursts than detectors on other satellites. The study, called the Burst and Transient Source Experiment (BATSE BATSE Burst and Transient Source Experiment ), indicates that gamma-ray bursts occur randomly and have a widespread distribution, Fishman says. He adds that the duration of gamma bursts detected by BATSE has varied from seconds to hundredths of seconds -- suggesting that the flashes may have several different types of sources. Other scientists have recently analyzed gamma-ray data recorded by three French-Soviet satellites. In the May 23 NATURE, researchers led by J.L. Atteia of the Center for the Study of Space Radiation in Toulouse, France, report that the distribution of gamma-ray bursts concentrates in the plane of our galaxy and falls off with distance -- a possible sign, they say, that the bursts originate in Verb 1. originate in - come from stem - grow out of, have roots in, originate in; "The increase in the national debt stems from the last war" the Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. . Over the next six months, says Fishman, BATSE may detect enough bursts to indicate their origin. |
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