CAPE CANAVERAL, Fla. (AP) – A comet is heading back our way after 50,000 years.
According to NASA, the dirty snowball was last seen during the Neanderthal period. It will come within 26 million miles (42 million kilometers) of Earth’s Mercury before speeding away again, unlikely to return for millions of years.
So look up, as opposed to the killer comet movie, “Don’t Look Up.”
Discovered less than a year ago, this harmless green comet is already visible in the northern night sky with binoculars and small telescopes, and perhaps with the naked eye in the darkest corners of the Northern Hemisphere.
It is expected to brighten as it approaches the end of January and rises higher on the horizon, best seen in the early morning hours. By February 10, he will be near Mars, which is a good sign. Sky watchers in the Southern Hemisphere will have to wait until next month for a glimpse.
Despite the large number of comets that have graced the sky over the past year, “this one probably looks a little bit bigger and therefore a little bit brighter and a little bit closer to Earth’s orbit,” said NASA’s comet and asteroid tracking guru. Paul Chodas.
This long-period comet, green from all the carbon in the gas cloud or coma surrounding the nucleus, was discovered last March by astronomers using the Zwicky Transient Facility, a wide-field camera at Caltech Palomar Observatory.
This explains its official, difficult name: Comet C/2022 E3 (ZTF).
On Wednesday, it will pass between the orbits of Earth and Mars at a relative speed of 128,500 mph (207,000 kilometers). Its core is thought to be about a mile (1.6 kilometers) across, and its tails are thought to stretch for millions of miles (kilometers).
The comet is not expected to be as bright as Neowise in 2020 or Hale-Bopp and Hyakutake in the mid-to-late 1990s.
University of Hawaii astronomer Karen Meech said in an email that “it will be bright because of the close pass of Earth … allowing scientists to do more experiments and the public to see a beautiful comet.”
Scientists are confident in their orbital calculations that the comet’s last swing in the planetary neighborhood of the solar system was 50,000 years ago.
But they don’t know how close it came to Earth or whether it was even visible to Neanderthals, said Chodas, director of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in California.
And when you come back, it’s harder to judge.
Each time a comet orbits the sun and planets, their gravitational tug slightly alters the ice ball’s path, causing major course changes over time. Another wild card: streams of dust and gas from a heated comet near the sun.
“We don’t know exactly how much they pushed this comet,” Chodas said.
The comet—a time capsule from the Solar System that formed 4.5 billion years ago—came from what is known as the Oort Cloud, far beyond Pluto. This deep-frozen haven for comets is thought to extend more than a quarter of the way to the next star.
Chodas, even if comet ZTF originated in our solar system, we cannot be sure that it will stay there. He added that if it is removed from the solar system, it will never return.
Don’t worry if you miss it.
“In the comet business, you’re just waiting for the next one, because there are dozens of them,” Chodas said. “And the next one might be bigger, brighter, closer.”
The Associated Press Department of Health and Science receives support from the Science and Education Media Group of the Howard Hughes Medical Institute. AP is responsible for all content.
