Jupiter's Temporary Moons

Posted by John Farrier in Science & Tech on September 16, 2009 at 6:29 pm

Sarah Zielinski writes in The Smithsonian that Jupiter, as the largest planet in our solar system, occasionally pulls comets into its orbit. Sometimes, as with comet Shoemaker-Levy 9 in 1994 (pictured), Jupiter’s gravity will even pull a comet into a direct impact. Zielinsky writes:

Astronomers from Japan and Northern Ireland, presenting their findings today at the European Planetary Science Congress, used observations of Comet Kushida-Muramatsu—from when it was discovered in 1993 and when it returned in 2001—to calculate the comet’s path over the previous century. They determined that the comet became a temporary moon when it entered Jupiter’s neighborhood in 1949. It made two full, if irregular, orbits around the planet, and then continued its travels into the inner solar system in 1962.

The researchers also predict that Comet 111P/Helin-Roman-Crockett, which circled Jupiter between 1967 and 1985, will again become a temporary moon and complete six loops around the planet between 2068 and 2086.

“The results of our study suggests that impacts on Jupiter and temporary satellite capture events may happen more frequently than we previously expected,” David Asher of Northern Ireland’s Armagh Observatory told the AFP.

Link

Photo: NASA

 
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Neatorama Shop » Home & Garden » Ice Trays

Did A Comet Wipe Out The Mammoths?

Posted by Miss Cellania in Science & Tech on January 2, 2009 at 12:05 pm

Scientists have long pondered an event 12,900 years ago that caused the disappearance of the Clovis people of North America and the extinction of large mammals such as the mammoth, mastodon, saber-toothed cat, and the North American camel. One theory is that a comet broke into fragments and showered burning material over the continent. Now there’s some evidence -a layer of nanodiamonds have been found at a layer of sediment buried 12,900 years ago. The diamonds could have only been formed by a high-pressure high-temperature event.

These diamonds are measured in nanometers — mere billionths of meters — and one of them would not suffice for an engagement ring unless the recipient had an extremely small finger. Indeed, these diamonds are visible only with the aid of the most advanced microscopes.

The wide distribution of the nanodiamonds could be a sign that the comet broke into pieces in space and that the fragments burned up explosively over a broad area of North America. The heat and pressure from the event transformed carbon on the planet’s surface into the tiny diamonds, the scientists said.

“Imagine these fireballs exploding in the air. A Clovis hunter standing and looking at these things would have seen a canopy of fire as these things came in and exploded,” said Allen West, a geophysicist and one of the paper’s co-authors. “There would have been no sound. There would have been massive explosions. Brilliant light, brighter than the sun. There would have been radiant heat — it would have been capable, at the very least, of giving him serious burns and, at the maximum, of incinerating him.”

This theory would explain the climate change at the time, when the warming planet was plunged into another, shorter ice age. Skeptics cite lack of a crater or other surface evidence in refuting the theory. Link -via Digg

 
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