CAPE CANAVERAL, Fla. (AP) — A comet is streaking back our way after 50,000 years.
The dirty snowball last visited during Neanderthal times, based on NASA. It is going to come inside 26 million miles (42 million kilometers) of Earth Wednesday before speeding away again, unlikely to return for tens of millions of years.
So do look up, contrary to the title of the killer-comet movie “Don’t Look Up.”
Discovered lower than a 12 months ago, this harmless green comet already is visible within the northern night sky with binoculars and small telescopes, and possibly the naked eye within the darkest corners of the Northern Hemisphere. It’s expected to brighten because it draws closer and rises higher over the horizon through the top of January, best seen within the predawn hours. By Feb. 10, it should be near Mars, an excellent landmark.
Skygazers within the Southern Hemisphere may have to attend until next month for a glimpse.
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While loads of comets have graced the sky over the past 12 months, “this one seems probably a little bit bit larger and subsequently a little bit bit brighter and it’s coming a little bit bit closer to the Earth’s orbit,” said NASA’s comet and asteroid-tracking guru, Paul Chodas.
Green from all of the carbon within the gas cloud, or coma, surrounding the nucleus, this long-period comet was discovered last March by astronomers using the Zwicky Transient Facility, a large field camera at Caltech’s Palomar Observatory. That explains its official, cumbersome name: comet C/2022 E3 (ZTF).
On Wednesday, it should hurtle between the orbits of Earth and Mars at a relative speed of 128,500 mph (207,000 kilometers). Its nucleus is considered a few mile (1.6 kilometers) across, with its tails extending tens of millions of miles (kilometers).
The comet isn’t expected to be nearly as vivid as Neowise in 2020, or Hale-Bopp and Hyakutake within the mid to late Nineteen Nineties.
But “it should be vivid by virtue of its close Earth passage … which allows scientists to do more experiments and the general public to give you the chance to see a fantastic comet,” University of Hawaii astronomer Karen Meech said in an email.
Scientists are confident of their orbital calculations putting the comet’s last swing through the solar system’s planetary neighborhood at 50,000 years ago. But they do not understand how close it got here 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 evaluate.
Each time the comet skirts the sun and planets, their gravitational tugs alter the iceball’s path ever so barely, resulting in major course changes over time. One other wild card: jets of dust and gas streaming off the comet because it heats up near the sun.
“We don’t really know exactly how much they’re pushing this comet around,” Chodas said.
The comet — a time capsule from the emerging solar system 4.5 billion years ago — got here from what’s referred to as the Oort Cloud well beyond Pluto. This deep-freeze haven for comets is believed to stretch greater than one-quarter of the technique to the subsequent star.
While comet ZTF originated in our solar system, we won’t be certain it should stay there, Chodas said. If it gets booted out of the solar system, it should never return, he added.
Don’t fret for those who miss it.
“Within the comet business, you simply wait for the subsequent one because there are dozens of those,” Chodas said. “And the subsequent one could be larger, could be brighter, could be closer.”
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