COLORADO (KXRM) — Earthlings! It’s time to look up to the sky over the next week as a rare comet last seen over 5,000 decades ago is set to pass near the planet.
The harmless comet known as C/2022 E3 (ZTF), or “green comet,” was last seen during the Stone Age more than 50,000 years ago, a time when Earth experienced an Ice Age and when Mastodons and saber-toothed cats roamed the planet.
On Thursday, Feb. 2, it will pass its closest to Earth again, hurtling between the orbits of Earth and Mars at a relative speed of 128,500 mph. Its nucleus is thought to be about a mile (1.6 kilometers) across, with its tails extending millions of miles.
Green from all the carbon in the gas cloud, or coma, surrounding the nucleus, this long-period comet was discovered last March by astronomers using the Zwicky Transient Facility, a wide field camera at Caltech’s Palomar Observatory. That explains its official, cumbersome name: comet C/2022 E3 (ZTF).
NASA said the comet was discovered inside Jupiter’s orbit.
Although it will be the closest to Earth in early February, astronomers said anyone in the Northern Hemisphere could start viewing the green glow now.
The comet is visible to the naked eye in the hemisphere’s darkest corners, but at 26 million miles away, the best way to see it is through a telescope or binoculars and in the predawn hours.
“Comets are notoriously unpredictable, but if this one continues its current trend in brightness, it’ll be easy to spot with binoculars, and it’s just possible it could become visible to the unaided eye under dark skies,” NASA said.
The comet is expected to brighten as it draws closer and rises higher over the horizon through the end of January. By Feb. 10, it will be near Mars, a good landmark.
“This comet isn’t expected to be quite the spectacle that Comet NEOWISE was back in 2020. But it’s still an awesome opportunity to make a personal connection with an icy visitor from the distant outer solar system,” NASA said.
Skygazers in the Southern Hemisphere will have to wait until next month for a glimpse.
“Green Comet” viewing tips:
- Stay away from city lights.
- View on a cloudless day.
- Around dusk is the best time to look up, while the moon is still dim.
- Use a telescope or binoculars for the best view.
- Try looking to the northwest for the green glow.
Scientists are confident in their orbital calculations putting the comet’s last swing through the solar system’s planetary neighborhood at 50,000 years ago. But they don’t know how close it came to Earth or whether it was even visible to the Neanderthals, said Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory in California.
When it returns, though, is tougher to judge.
The comet — a time capsule from the emerging solar system 4.5 billion years ago — came from what’s known as the Oort Cloud well beyond Pluto. This deep-freeze haven for comets is believed to stretch more than one-quarter of the way to the next star.
While comet ZTF originated in our solar system, we can’t be sure it will stay there, Chodas said. If it gets booted out of the solar system, it will never return, he added.
The Associated Press contributed to this report.