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Global warming on Pluto
Forgive me, but I couldn't pass this up.
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"Astronomers who observed a rare cosmic event in July have announced that
Pluto's atmosphere has undergone drastic changes in the past 14 years.
Pluto, the farthest planet from the sun, has never been seen clearly from
Earth, or even from space telescopes. However, in an "occultation" on July
19, the planet passed directly in front of the star P126A, blocking the
star's light. Marc Buie of Lowell Observatory in Flagstaff, Ariz., and Oscar
Saa of Cerro Tololo Inter-American Observatory in Chile used a 14-inch
portable telescope in northern Chile to observe the event. By recording the
dimming of the starlight, Buie's team was able to calculate the density,
pressure and temperature of Pluto's atmosphere.
During observations of the last occultation in 1988, the light from the star
winked out completely, suggesting a "smog" layer over Pluto or a sharp
decline in its atmospheric temperature. However, during the recent viewing,
the star's light gradually dimmed as the planet passed in front. Comparing
the two results, James Elliot of the Massachusetts Institute of Technology
said one possible explanation is that the "smog" layer, or the temperature
drop, that extinguished the starlight the first time has now dropped to a
lower altitude or disappeared. Another possibility, according to Elliot, is
that Pluto is undergoing global warming.
The scientists hope to obtain more information during an occultation
predicted for August 20, 2002, when Pluto will pass in front of the star
P131.1. These events are becoming more common because Pluto is moving into
line with the Milky Way, where stars are more abundant, Elliott said.
The National Science Foundation (NSF) partially supports this research, and
scientists used NSF's Cerro Tololo observatory to help predict when and
where the event could be observed. [Amber Jones]"
--
NSF Custom News Service
http://www.nsf.gov/home/cns/start.htm
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
E-mail: jenday1@email.msn.com (H)
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