Once the sun sets on a clear night, the newly discovered comet NEOWISE is visible just below the bowl of the Big Dipper.
The comet was discovered March 27 by a team of astronomers working on a NASA project to detect asteroids near earth. The comet’s name is an acronym for the project — Near Earth Object Wide-field Infrared Survey Explorer.
“As comets go, this one is pretty spectacular,” said Meredith Hughes, associate professor of astronomy at Wesleyan University in Middletown. “Naked-eye comets tend to come around only about once a decade or so. I’ve only seen three in my lifetime. Comet NEOWISE will be back, but not for the next 6,800 years. It’s worth staying up past your bedtime some night.”
Comets are called “dirty snowballs” by astronomers, according to Hughes, since they are chunks of ice, rock and other space junk left over from the early days of our solar system. Since they orbit the sun, they are considered a part of our solar system.
“But their orbits are so far that you can’t see them because they are really small,” said William Herbst, professor of astronomy at Wesleyan. “... We only see them when they come close to the sun and their orbits take thousands of years. This one may have passed the sun before, but no one saw it. (Or) people might’ve seen it but they really didn’t write it down.”
NEOWISE is approximately the size of Manhattan. Its tail is about the same size as 12 full moons placed side to side.
“It passed close to the sun a few months ago and now it’s on its way out and when it went close to the sun, the ice melts and it becomes like vapor, fog,” Herbst said.
“That fog creates the tail of the comet. You can see the tail really nicely with binoculars. The tail stretches actually millions of miles through space. The comet is small, but the tail is huge, millions of miles across. That’s why we can see it even though it is so far away.”
NEOWISE was closest to Earth on Tuesday, July 21 and will be getting fainter every night.
“It’s receding from the sun and receding from the Earth, which means we don’t have too much longer to see it,” said Jim Mazur, newsletter editor for the Astronomical Society of New Haven. “I mean it’ll be up there but if you want a good view of it, the best time to look would be the next clear night that we have because it’ll be getting dimmer over the next few weeks.”
To spot NEOWISE, look toward the northwest underneath the Big Dipper. It is also important to be away from a lot of artificial light.
“If you were looking from downtown New Haven, you probably would not see it with the naked eye,” Mazur said.
If you put your fist out at arm’s length and point it toward the horizon, the comet should be just above your fist, according to Herbst.
Also pay attention to any fuzziness you see in the corner of your eye.
“With faint objects like comet NEOWISE, you can actually see them better out of your peripheral vision,” said Hughes.
“It might even seem to disappear when you try to look directly at it, but just be patient. Wait for your eyes to adjust fully to the dark, and keep sweeping your eyes slowly across the sky, waiting to catch it at the edges of your vision.”
Even though it looks as if it is close to the earth, NEOWISE is not dangerous.
“It’s about 60 million miles away and it’s heading out from where it came from so it’s no a danger to us,” Herbst said.