Tuesday, November 07, 2006

A comet gets too close to the sun

In the Greek myth of Daedalus and Icarus, the father-son duo escape from the labyrinth by making wings out of feathers and wax and then fly out of the maze. Icarus ignores his father's warnings, flies too close to the sun, and the wings melt. Icarus falls and is killed.

Each year, many comets, real balls of ice and dust, meet the same fate. These "sungrazing" comets seem to be the remnants of one or more regular comets that orbited too close to the sun and were pulled apart into a string of thousands of miniature comets. The SOHO spacecraft, a sun-viewing spacecraft, is constantly watching the sun. It has spied over 1200 comets plunging into the sun, most of which never return -- the sun completely melts them!

Most of these sungrazing comets are very faint and unimpressive. However, this week a fairly bright one appeared. You can watch a movie at this website. The comet comes in from the lower right. The sun is hidden behind the blue disk in the middle of the picture (or else it would completely blind the camera). The white circle gives the approximate size of the sun. The bright "star" to the upper left of the sun is the planet Venus.

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