The comet will be visible from November to December and should pass closest to the sun on Thanksgiving Day, said Matthew Knight, a postdoctoral research scientist at the Lowell Observatory in Flagstaff, Ariz. The best time to view it from this state will be in late December right after sunset and just before sunrise, he said.
Astronomers said they expect ISON — named after the Russian observatory where it was first discovered in September 2012 by two amateur stargazers — to fly closer to the sun than most comets, within 2.7 solar radii or about 1.8 million kilometers from the sun’s center. This proximity will heat up the comet, making it abnormally bright, Knight said.
“We think this comet will be as bright as the full moon, which will be amazing,” said Dennis Bodewits, assistant research scientist in the university’s astronomy department.
The comet could make for more than just a beautiful display — it could be a rare opportunity for scientists to learn more about the composition of comets and their role in outer space.
Assuming the comet survives its path near the sun, Knight said, the extreme heat would cause ice and other heavy metals to evaporate off its surface.
If this happens, astronomers could potentially detect the various elements using solar telescopes and other instruments, Bodewits said.
“We want to compare the composition of this comet to the composition of the sun and other planets,” Knight said.
Since ISON’s discovery, astronomers from this university and the Lowell Observatory have been working together as they track the comet’s path using NASA’s Swift satellite. They will observe it with the Hubble Space Telescope on May 2, Bodewits said.
If it stays on track, the comet would rank among the brightest in history, he said.
But comets are unpredictable and don’t always behave the way astronomers expect, Knight said, which is why some stargazers are waiting to plan viewing sessions until closer to ISON’s approach.
“There’s no way to really know how they’re going to turn out,” said Elizabeth Warner, observatory coordinator at this university. “It may fall about, completely shatter and not be visible at all.”
Steffi Yen, president of AstroTerps, said she plans to watch the comet wherever she is when it passes Earth.
“Looking at the night sky is something really beautiful,” said Yen, a senior astronomy and physics major. “It’s crazy that there are things going on so far away from us that we don’t know too much about. There’s a lot to learn. [Astronomy] is very different from other sciences.”
A few weeks ago, Yen waited on the top of Regents Parking Garage with a pair of binoculars in hand, hoping to catch a glimpse of the comet Pan-STARRS.
It was one of the coolest space phenomena she’s ever seen, Yen said.
The last significant comet was Ikeya-Seki, discovered by two Japanese amateur astronomers in 1965, Knight said. Because it traveled so close to the sun, scientists were able to detect heavy metals leaping off a comet for the first time, he said.
ISON does not pose any threat to Earth, even though its path is nearby, Bodewits said. Asteroids that travel toward the Earth from behind the sun — such as the one that hit Russia in February — are dangerous because scientists can’t see them coming, he added.
“We can’t observe toward the sun,” he said. “It’s like looking into a car’s headlights.”
As ISON approaches the sun in the coming months, astronomers plan to keep their eyes on the comet and its path.
“We’re trying to raise awareness of the comet to make sure that observatories all over the world are aware of it,” Knight said. “It’s such a unique opportunity to study comets … We call it a dynamically new comet. We don’t get a chance to study many of those.”