The
potentially dazzling Comet ISON is currently visible to the unaided eye
— a milestone for the comet’s much-anticipated pass through the inner
solar system — but its future all depends in how it reacts to a close
Thanksgiving encounter with the sun, comet observers say. Comet ISON can
be seen low in the southeastern sky an hour before dawn, weather
permitting, but it is en route for an extremely close flyby of the sun
on Thanksgiving Day (Nov. 28). Will it break apart due to the sun’s
gravity and heat, or will the comet emerge victorious from its solar
rendezvous and shine bright in the night sky? No one knows for sure yet,
said Alan MacRobert, senior editor for Sky & Telescope magazine, in
a skywatching guide this week. ”We might witness a nice, long-tailed
comet visible to the naked eye that will leave millions of people with
fond memories for a lifetime,” MacRobert said. ”Or maybe it will be a
small comet for sky hunters using binoculars and a good map of its
position. Or it might yet break up and vanish.” [How to See Comet ISON:
An Observer's Guide] Comet ISON’s nucleus, or core, will have to survive
its closest encounter with the sun on Nov. 28 around 2 p.m. EST. (1900
GMT) Surface temperatures are expected to peak at 2,700 degrees
Fahrenheit (4,900 degrees Celsius). That’s hot enough to melt iron, let
alone the ices that make up the comet’s core. More
The
potentially dazzling Comet ISON is currently visible to the unaided eye
— a milestone for the comet’s much-anticipated pass through the inner
solar system — but its future all depends in how it reacts to a close
Thanksgiving encounter with the sun, comet observers say. Comet ISON can
be seen low in the southeastern sky an hour before dawn, weather
permitting, but it is en route for an extremely close flyby of the sun
on Thanksgiving Day (Nov. 28). Will it break apart due to the sun’s
gravity and heat, or will the comet emerge victorious from its solar
rendezvous and shine bright in the night sky? No one knows for sure yet,
said Alan MacRobert, senior editor for Sky & Telescope magazine, in
a skywatching guide this week. ”We might witness a nice, long-tailed
comet visible to the naked eye that will leave millions of people with
fond memories for a lifetime,” MacRobert said. ”Or maybe it will be a
small comet for sky hunters using binoculars and a good map of its
position. Or it might yet break up and vanish.” [How to See Comet ISON:
An Observer's Guide] Comet ISON’s nucleus, or core, will have to survive
its closest encounter with the sun on Nov. 28 around 2 p.m. EST. (1900
GMT) Surface temperatures are expected to peak at 2,700 degrees
Fahrenheit (4,900 degrees Celsius). That’s hot enough to melt iron, let
alone the ices that make up the comet’s core. More
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