Scientists are speculating whether ISON, a comet that has spent 4.5 billion years at the edge of the solar system, will implode from the heat of strafing the sun on Thursday.
Astronomers call ISON a relic from when our solar system was
formed, adding that it has been travelling to meet the Sun for
over a million years, and will only ever be seen once in history.
This “comet of the century” is expected to provide clues on the
formation of the planets.
"The reason we study comet ISON to begin with is it's a
relic," Carey Lisse, a senior research scientist with Johns
Hopkins Applied Physics Laboratory, said during a NASA news
conference on Tuesday.
"It's a dinosaur bone of solar system formation. You need
comets in order to build the planets. This comet has been in a
deep freeze half way to the next star for the last 4.5 billion
years. It's just been coming in over the last few millions years
and possibly even started around the dawn of man."
This is the comet’s first trip into the inner solar system, NASA
scientists said, adding that it means the comet is still made of
pristine matter from the earliest days -- its top layers never
having been lost, and so dubbing the celestial body “a
time capsule from the solar system's birth.”
ISON originated in the Oort cloud, which lies a light year from
the sun, and will give the star that has pulled it steadily
forward for so long a close of shave on Thursday, November 28 at
18:38 GMT. The comet will then come to within 1.1 million
kilometers of the solar surface, NASA officials said.
Here the comet’s inward journey through our planetary system will
end. Scientists are speculating whether it will break up due to
the intense heat and gravity forces of the sun, or if it will
remain intact and speed back away.
“There are a lot of things that could happen to this comet.
Will it fall apart? Will it not fall apart? Will it fade away? We
need to see what it does and when it does it and why it behaved
the way it did," said Karl Battams, an astrophysicist with
the Naval Research Laboratory.
Comets are balls of primordial ice, rock and dust left over from the formation of our solar system. They are relatively small, at times active, objects whose ices can vaporize in sunlight forming a visible atmosphere around it called a ‘coma’ or a ‘tail.’
ISON mostly consists of ice and cosmic dust and according to NASA
estimates there is a 70 percent chance it won't survive traveling
so close to the sun's hot surface. The intense sunlight will heat
the comet to about 2,700C when it comes closest to our G type
star.
"It's going from a deep freeze to the furnace of the sun and
we're going to watch it bake and boil," said Lisse.
NASA scientists also added that some astronomers believe that the
comet already is breaking apart.
“We just don’t know if it’s in one piece or not,” said
Battams.
Currently the comet is not clearly visible because it is too
close to the sun. If the comet does not break up under the star’s
blazing heat, it could produce a bright, once in a lifetime
celestial show during the first and second weeks of December as
it passes near Earth on its way back out.
Comet ISON, catalogued as C/2012 S1, was first spotted in
September 2012 by Russian researchers Vitaly Nevsky and Artyom
Novichonk using the International Scientific Optical Network’s
(ISON) 0.4-meter (16-inch) telescope. It was named in honor of
the institution and dubbed the "comet of the century."
Some scientists at first thought ISON was several kilometers in
diameter and would rival the brightness of a full moon. However,
as the comet passed Mars, the NASA orbiter took photos of it
showing that it is smaller than most comets.