A comet is heading for a close encounter with the sun later this month, and if it is not vaporized or torn apart, it should be visible to the naked eye in December.
Comet ISON is expected to pass just about 1 million kilometers from the sun’s surface on Nov. 28. Scientists are not sure how ISON will hold up. As it blasts around the sun, traveling at 377 km per second the comet will be heated to about 2,760 degrees C, hot enough to vaporize not just ice in the comet’s body, but also rock and metal. If the heat does not kill ISON, the sun’s gravity may rip it apart.The comet was discovered in September 2012 by two amateur astronomers using Russia’s International Scientific Optical Network, or ISON, for which the comet is named. It was extraordinarily bright at the time, considering its great distance beyond Jupiter’s orbit, raising the prospect of a truly cosmic spectacle as it approached the sun.That is because heat from the sun causes ice in a comet’s body to vaporize, creating bright, distinctive tail.