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Green Comet 2022 E3 ZTF is close to Earth. The astronomer who found it offers tips to find it.

Bryce Bolin and Caltech Senior Staff Scientist Frank Masci discovered it while looking for asteroids in March. The best chance to see it with binoculars is from Jan. 12 to Feb. 1 over the northern hemisphere.

By Carlos R. Muñoz Globe Staff,Updated January 10, 2023, 6:00 a.m.
Comet C/2022 E3 (ZTF) was discovered by astronomers using the wide-field survey camera at the Zwicky Transient Facility this year in early March. Since then the new long-period comet has brightened substantially and is now sweeping across the northern constellation Corona Borealis in predawn skies. It's still too dim to see without a telescope though. This fine telescopic image from Dec. 19 shows the comet's brighter greenish coma, short broad dust tail, and long faint ion tail stretching across a 2.5 degree wide field-of-view. On a voyage through the inner Solar System comet 2022 E3 will be at perihelion, its closest to the Sun, in the new year on January 12 and at perigee, its closest to our fair planet, on Feb. 1.Dan Bartlett

Bryce Bolin said he’s always been more of an educator than a scientist. Nine months ago, the doctor in astrophysics was hunting asteroids at California Institute of Technology’s Palomar Observatory when assisted artificial intelligence flagged an unknown comet.

Bolin, now a NASA Postdoctoral Program Fellow at Goddard Space Flight Center in Maryland, and Caltech Senior Staff Scientist Frank Masci confirmed the object the computer tipped them off to was indeed a long-period comet on a voyage through the inner solar system, which will soon be visible over New England.

The Comet 2022 E3 Zwicky Transient Facility, named for the asteroid survey, has become known as the “green” comet because the coma of the comet (a ball of decomposing carbon molecules common in all comets) appears green on film. It makes its closest approach (perigee) to Earth on Feb. 1, when it will be approximately 28 million miles from our planet.

C/2022 E3 should begin showing up in the night sky on Jan. 12, when it is closest to the sun (perihelion). It will be the brightest on Feb. 1, Bolin said.

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Bolin, who spoke to the Globe on the phone Friday, said if we’re lucky the comet will be visible to the naked eye. It will look like a white smudge in the sky north of the Little Dipper, he said.

Bolin was at the Las Vegas Airport waiting for his flight surrounded by the sound of slot machines and commuters. He didn’t gamble during Friday’s layover, instead flipping through a bonanza of Twitter posts from people around the world who photographed the comet he helped discover.

Bolin said he wants to inspire people to take part in science and his comet has sparked global interest.

“This is an opportunity for people to explore the universe firsthand,” he said.

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In Rhode Island, the best place to see the comet will be on the state’s dark southern coast. Scott MacNeill, director at Frosty Drew Observatory, said the park surrounding the space telescope is a good spot for space viewing. Those who can’t make it to Charlestown could look to the sky from the beach in coastal spots like Newport and Point Judith.

In Massachusetts, Maine, and New Hampshire, the coastline, ski resorts, or mountaintops could be your best bets.

MacNeill and Bolin said to temper expectations. Comets can be finicky.

“Comets are the cats of the solar system; they do whatever they want,” Bolin said. “Like cats they have fluffiness. Comets have been observed to have peculiar behaviors, like fragmenting or disintegrating. But there is not really a strong correlation between the distance to the sun and the kind of disintegration events that occur. It could break apart on its way in before it ever comes close to the sun, or even after.

They are confident that the C/2022 E3 will be visible with a basic pair of binoculars or long-exposure photography just about anywhere in the US.

MacNeill said if the comet is bright, Frosty Drew will announce a public event.

While there have been reports that the comet last visited Earth 50,000 years ago, a timeframe that puts it around the Paleolithic Age or the time of Neanderthals, Bolin said it is unknown if it has ever swung past earth. We may be the first to lay eyes on C/2022 E3.

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“If you take literally the orbital parameter of this object and compute a time period, then that’s what gives you a provisional estimate that it passed earth 50,000 years ago,” Bolin said. ”But you have to put an asterisk on that.”

The last comet visible to the naked eye was Comet NEOWISE, which gave people dealing with the peak of the COVID-19 pandemic a stunning show.

But NEOWISE was tough to see, MacNeill said.

As C/2022 E3 approaches the sun it will be exposed to increased radiation and solar winds that will change it from a solid to a gaseous state. The volatile materials within the icy comet could fracture causing it to illuminate tenfold, or even disintegrate, Bolin said. The demise of the ice ball is unlikely but would provide scientists with an incredibly rare opportunity to observe the death of a comet.

“We secretly hope it will disintegrate,” Bolin said. “That’s where the most interesting science is.”

Carlos Muñoz can be reached at carlos.munoz@globe.com. Follow him on Twitter @ReadCarlos and on Instagram @Carlosbrknews.

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