| Subject: Missing moon baffles astronomers |
Author:
Betty
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Date Posted: 11:22:09 04/16/04 Fri
In reply to:
Betty
's message, "Hubbble telescope to die & be destoyed" on 12:26:05 02/15/04 Sun
A search with the Hubble Space Telescope has failed to spot the tiny moon astronomers were confident they'd find circling Sedna, the most remote body ever spotted circling our sun.
"I'm completely baffled," said Sedna's discoverer, California Institute of Technology astronomer Mike Brown. Sedna orbits the sun at a distance of 8 billion miles, more than twice as far out as Pluto.
When its discovery was announced last month, Brown said measurements of its reddish light showed changes that seemed to repeat about every 20 days. That was a hint Sedna was spinning once in 20 days and in a gravitational "lock" with a sizable orbiting moon.
Most solo objects the size of Sedna rotate once every few hours. Pluto, a third larger than Sedna, rotates once every six days, a pace that puzzled astronomers until 1978, when they discovered a moon circling the planet every six days.
But when Hubble was aimed at Sedna on March 16, there was no moon. There's a slight chance the little moon was directly behind or in front of Sedna, or the initial light measurements were flawed. More observations are planned.
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