Sunday, October 17

Will comet ISON survive its near brush with the Sun?

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WASHINGTON: US astrophysicists are split over what will happen when the comet ISON passes near the sun today, but a majority think it will break apart.

Comets are frozen balls of space dust left over from the formation of stars and planets billions of years ago.

So when one of them zips close to a hot star, like the Sun, sometimes the icy core… melts.

“Many of us think it could break up into pieces, and some people think it won’t survive at all” after its brush near the Sun, said comet expert Carey Lisse of the Johns Hopkins Applied Physics Laboratory during a telephone press conference.

But he conceded, there are others who think the icy mass “will actually survive and come back out” on the other side of the sun, albeit somewhat shrunken down from its encounter with the Sun’s heat.

ISON will be just 1.17 million kilometers (727,000 miles) from the sun as it passes by where it will be hit by temperatures of around 2,700 degrees Celsius.

“I think it has a maybe 30 per cent chance to make it” past the sun intact, Lisse said.

The comet “is like a loose snow ball,” he explained, saying it is “maybe half or a third water and it’s rather weak.” It’s also smaller than most comets, currently measuring around 1.2 kilometers in diameter.

“The average size for a comet is about three kilometers diameter, so this comet is maybe about half the size of the average, typical comet,” he said. — AFP