Comet now bigger than the Sun

Space Weather News for Nov. 15, 2007

GIANT COMET: University of Hawaii astronomers have measured the diameter of Comet 17P/Holmes: 1.4 million kilometers. This makes the exploding comet bigger than the sun and now the largest object in the solar system. Not surprisingly, the comet is visible to the naked eye; with only a backyard telescope you can watch its gigantic debris cloud expand from night to night. Nov. 19th is an especially good night to look: Comet Holmes will glide by *Mirfak, the brightest star in the constellation Perseus, and appear to swallow it.

Visit SpaceWeather.com for a sky map and images.

(Note: The sun remains by far the most massive object in the solar system. Comet 17P/Holmes' diaphanous atmosphere of dust and gas, which is what the astronomers measured, contains less mass than a typical asteroid. In spite of its great size, Comet Holmes is a lightweight that won't be deflecting the orbits of planets or causing any other such catastrophes.)

ROSETTA FLYBY: On Nov. 13th, the European Space Agency's comet-chasing Rosetta spacecraft buzzed Earth, passing only 5300 km above the southern hemisphere. During the high-speed gravity assist maneuver, Rosetta snapped some fantastic pictures including close-up shots of Antarctic icescapes and glittering views of city lights at night.

See Rosetta's amazing photos at SpaceWeather.com.

*Mirfak (Alpha Perseus): young male energy; a young warrior proud of his strength.