BIG COMET PLUNGES TOWARD THE SUN: Comet Lovejoy (C/2011 W3) is diving into the sun and furiously vaporizing as it approaches the stellar surface. The Solar and Heliospheric Observatory (SOHO) is recording the kamikaze plunge:
"This is, without any doubt, the brightest sungrazing comet that SOHO has ever seen," says comet researcher Karl Battams of the Naval Research Lab in Washington DC.
The comet's nucleus, thought to be twice as wide as a football field, will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16. At such close range, solar heating will almost certainly destroy the comet's icy core, creating a cloud of vapor and comet dust that will reflect lots of sunlight.
"If Comet Lovejoy gets as bright as magnitude -4 or -5, there is a tiny but non-zero chance that it could become visible in the sky next to the sun," says Battams.
Indeed, something similar happened to Comet McNaught in January 2007 when it was visible in broad daylight:
gallery. Standing in the shadow of a tall building to block the sun allowed the comet to be seen in blue sky nearby.
Caution: Do not point unfiltered optics at or near the sun; focused sunlight can cause instant blindness.
"Comet Lovejoy will be reaching perihelion (closest approach to the sun) right around sunset on Dec. 15th for people in the US East, Central, Mountain, and Pacific time zones," continues Battams. "Be alert for the comet to the left of the sun at that time."