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Science briefs: August 17-18
Posted: Mon, Aug 19, 2002, 8:04 AM ET (1204 GMT)
- Astronomers have found evidence that Pluto's atmosphere is cooling as the planet recedes from the Sun. Scientists analyzing data from a July occultation, when Pluto passed in front of a star as seen from the Earth, found that the atmosphere has cooled by up to 30 degrees Celsius since a similar occultation in 1988. Astronomers plan to observe a similar occultation on August 20.
- Galaxy clusters may be the source of the majority of the gamma rays observed in the universe. Astronomers studied nearly 2,500 galaxy clusters using data from the now-defunct Compton Gamma Ray Observatory and found that the sky around more massive clusters have stronger gamma rays. The observations match one model of gamma-ray production, the Loeb-Waxman theory, and argue against another model that predicts that active galaxies dubbed "blazars" produce the most gamma rays.
- The recent solar maximum was less intense than the previous one, but did have some affects on spacecraft and electrical grids, according to UPI. The recent solar maximum had two peaks, in April 2000 and late 2001. Unlike the 1989 solar max, which damaged the electrical grid in Quebec, the recent solar max did cause similar failures, although scientists did say an April 2001 event caused a strain on electrical systems in New England. The recent solar max may also be responsible for satellite failures that led to $500 million in insurance claims in the last five years.
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