Cape Canaveral, Fla. (AP) — A comet is headed our way again 50,000 years later.
Dirty Snowball was last visited during Neanderthal times, according to NASA. It will come within 26 million miles (42 million kilometers) of Earth on Wednesday before speeding up again, and is unlikely to return for millions of years.
So look up, as opposed to the Killer-Comet headline “Don’t Look Up”.
Discovered less than a year ago, this harmless green comet is already visible in the northern night sky with binoculars, small telescopes and perhaps with the naked eye in the darkest corners of the Northern Hemisphere.
It’s expected to clear as it approaches and rise higher above the horizon through late January, and is best seen in the early hours of the morning. On February 10, it will be near Mars, which is a nice landmark. Skywatchers in the Southern Hemisphere will have to wait until next month to catch a glimpse.
While many comets have graced the sky over the last year, “it seems like this one might look a little bigger and therefore a little brighter as it gets closer to Earth’s orbit,” said NASA asteroid and comet tracking expert Paul. Chodas.
The green long-period comet of all the carbon in the gas cloud, or coma, surrounding the nucleus, was detected last March by astronomers using the Zwicky Transit Facility, a wide-field camera at Caltech’s Palomar Observatory.
That explains its official damning name: Comet C/2022 E3 (ZTF).
On Wednesday, it will hurtle between Earth and Mars orbits at a relative speed of 128,500 mph (207,000 km). Their cores are believed to be about a mile (1.6 kilometers) in diameter, and their tails extend 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.
“It will be bright thanks to a near-Earth gap… allowing scientists to carry out more experiments and the public to see the beautiful comet,” said Karen Meek, an astronomer at the University of Hawaii, in an email.
The scientists are confident of their orbit calculations, which show the comet’s last swing through the solar system’s planetary neighborhood 50,000 years ago.
They didn’t know how close it was to Earth or whether it was visible even to Neanderthals, said Chodas, director of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in California.
However, when he returned, the verdict was even harsher.
Whenever a comet passes by the sun and planets, its gravitational pull slightly changes the trajectory of the ice ball, causing a significant change in trajectory over time. Another wild card: the jets of dust and gas that shoot up from comets as they heat up near the sun.
“We don’t know exactly how far they pushed this comet,” said Chodas.
Comets – time capsules from the nascent solar system 4.5 billion years ago – originate in what is known as the Oort Cloud beyond Pluto. The deep freezing heaven for this comet is thought to extend more than a quarter of the way to the next star.
Chodas says that even if Comet ZTF originates from our solar system, we can’t be sure that it will still be there. He added that if he was expelled from the solar system, he would never return.
Don’t worry if you miss it.
“In the comet field, you just have to wait for the next one because there are dozens of them,” said Chodas. “And the next one might be bigger, might be brighter, might be closer.”
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