Rare green comet to streak past Earth this week

CAPE CANAVERAL, Florida — A comet is blasting our way after 50,000 years.

According to NASA, the muddy snowball was last visited during the time of the Neanderthals. It will pass within 26 million miles of Earth on Wednesday and then drift away again, unlikely to return in millions of years.

So look up, contrary to the name of 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 become brighter as it approaches and rises above the horizon towards the end of January, best seen in the wee hours. By February 10, he will be near Mars, a good guide. Southern hemisphere skywatchers will have to wait until next month to get a glimpse of it.

While a lot of comets have graced the skies over the past year, “this one seems to be probably a little bigger and therefore a little brighter, and it’s getting closer to Earth’s orbit,” said the NASA comet and asteroid tracking guru. Paul Hodas.

PREVIOUSLY: Bright green comet will make the only flight past the Earth

Green due to all the carbon in the gas cloud or coma surrounding the nucleus, this long-period comet was discovered by astronomers last March with the Zwicky Transient Facility, a wide-field camera at Caltech’s Palomar Observatory. This explains its official cumbersome name: Comet C/2022 E3 (ZTF).

On Wednesday, it will fly between the orbits of Earth and Mars at a relative speed of 128,500 miles per hour. Its core is believed to be about a mile in diameter, while its tails extend for millions of miles.

The comet is not expected to be as bright as Neowise in 2020 or Comet Hale-Bopp and Hyakutake in the mid to late 1990s.

MORE: The best viewing platforms of 2023 not to be missed

But “it will be bright due to the close passage of the Earth … allowing scientists to do more experiments and the public to see the beautiful comet,” University of Hawaii astronomer Karen Meech said in an email.

Scientists are confident in their orbital calculations that the comet’s last pass through the solar system’s planetary neighborhood is 50,000 years ago. But they don’t know how close it came to Earth or if it was even visible to Neanderthals, said Chodas, director of the Near-Earth Object Center at NASA’s Jet Propulsion Laboratory in California.

However, when he returns, it is more difficult to judge.

Each time the comet circles around the sun and planets, their gravitational pull slightly changes the trajectory of the ice ball, resulting in major course changes over time. Another wild card: jets of dust and gas emanating from a comet as it heats up near the Sun.

“We don’t actually know exactly how hard they push this comet,” Chodas said.

The comet — a time capsule from the forming solar system 4.5 billion years ago — came from what is known as the Oort Cloud far beyond Pluto. This freezer haven for comets is thought to extend more than a 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. He added that if he was kicked out of the solar system, he would never return.

Don’t worry if you miss it.

“In the case of comets, you just wait for the next one because there are dozens of them,” Chodas said. “And the next one might be bigger, might be brighter, might be closer.”