This is a reminder that this comet is on the way
in. It has the potential to be spectacular. It is already charging up and outgassing
furiously and it will have a visible tail coming in. After that we will simply see. The potential is there.
We will keep an eye on it here as it passes
through. It is too good to miss.
It may even become a media event to remind us that
our violence is silly.
Potential 'comet of
the century' ISON to buzz Mars soon
Megan Gannon
Sep. 4, 2013 at 11:32 AM ET
Earthlings may be treated to a dazzling celestial display
this fall as Comet ISON makes a suicidal plunge toward the sun. But spacecraft
exploring Mars are poised to get close-up views of the icy wanderer first.
"Comet ISON is paying
a visit to the Red Planet," astronomer Carey Lisse of the Johns Hopkins
University Applied Physics Lab said in a statement. "On Oct 1st, the comet
will pass within 0.07 AU from Mars, about six times closer than it will ever
come to Earth."
One AU, or astronomical unit, is the distance between the
Earth and sun, about 93 million miles (150 million kilometers). Comet ISON's Mars flyby, at
0.07 AU, will be about 6.5 million miles (10.4 million km).
Comet ISON may brighten enough for NASA's Mars rover
Curiosity to see it from the surface of the Red Planet. However, Lisse said the
best chance for a Martian sighting lies with the space agency's Mars
Reconnaissance Orbiter. [Photos of Comet ISON: A Potentially Great Comet]
The MRO satellite is equipped with a powerful telescope
named HiRISE that is intended to take pictures the Red Planet's surface. But
researchers think the instrument will be capable of turning its gaze into space
to detect the comet's atmosphere and tail.
"The camera is designed for rapid imaging of
Mars," the HiRISE's telescope's principal investigator, Alfred McEwen of
the University of Arizona, said in a statement. "Our maximum exposure time
is limited compared to detectors on other space telescopes. This is a major
limitation for imaging comets. Nevertheless, I think we will detect Comet
ISON."
The satellite is set to take observations of the comet on
Sept. 29 and Oct. 1 and 2. The observations could help researchers prepare for
a comet that is set to fly even closer to Mars in October 2014.
"The science value of observing Comet ISON is hard
to predict. We've never tried such a thing before," McEwen said.
"However, this is good practice for Comet Siding Spring, which will pass
much closer to Mars in 2014."
A total of 16 NASA spacecraft and even more telescopes on Earth will be observing Comet ISON as it approaches.
"Our goal is to have every telescope on Earth
pointed at the comet when it emerges from the sun," says Lisse. "The
Mars flyby will give us a sneak preview, providing data we need to predict what
we might see."
On Nov. 28 — Thanksgiving Day in the United States — ISON
will make its closest approach to the sun, or perihelion, skimming just 730,000
miles (1.2 million km) or so above the surface.
If the icy dust ball doesn't get ripped apart by extreme
solar forces, some astronomers have said it could be the "comet of the century,"
possibly shining brightly enough to be seen during the daytime.
"If ISON's nucleus is much bigger than 0.5 km, it
will probably survive its Thanksgiving Day brush with the sun," Lisse
said. "It could turn into one of the most spectacular comets in many
years."
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