A "once-in-a-lifetime comet" that hasn't been seen in the solar system for 50,000 years is set to reach its brightest moment this week as stargazers will be able to spot it with just a telescope or binoculars.
According to Chicago's Adler Planetarium, the comet, informally known as the "green comet," "recently made its closest approach to the sun, after having traveled tens of thousands of years from the far fringes of the solar system." It is expected to be brightest around Feb. 1 as it reaches its closest point to Earth.
The comet will be "just slightly brighter than 6th magnitude," the planetarium notes, meaning the comet will be at the "faintest an object can be seen without optical aid in a very clear, very dark sky."
But it won't look like what many might imagine a comet to look like - even in photos.
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"It will be more like a faint, fuzzy glow or smear of light," the planetarium reported. "Under a city or suburban sky, you’ll need binoculars or a small telescope to actually see this comet. Even far from city lights, you’ll likely still need binoculars because when the comet is brightest, the bright Moon will be in the sky at the same time, making viewing more difficult."
Discovered less than a year ago, the harmless green comet already is visible in the northern night sky with binoculars and small telescopes, and possibly the naked eye in the darkest corners of the Northern Hemisphere.
On Wednesday, the comet will come within 26 million miles of Earth. It will hurtle between the orbits of Earth and Mars at a relative speed of 128,500 mph. Its nucleus is thought to be about a mile cross, with its tails extending millions of miles.
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"But don’t worry, as you are gazing at this cosmic fuzzball, there’s no threat of it crashing into Earth, as it will be 26 million miles away from us at its closest approach," the planetarium said.
As for those in the Chicago area, whether it will be visible on that day remains unclear, with partly to mostly cloudy skies in the forecast, according to the NBC 5 Storm Team.
By Feb. 10, the comet will be near Mars. It'll then speed away again, unlikely to return for millions of years.
The comet isn’t expected to be nearly as bright as Neowise in 2020, or Hale-Bopp and Hyakutake in the mid to late 1990s.
But “it will be bright by virtue of its close Earth passage ... which allows scientists to do more experiments and the public to be able to see a beautiful comet,” University of Hawaii astronomer Karen Meech said in an email.
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.
Every time the comet skirts the sun and planets, their gravitational tugs alter the iceball’s path ever so slightly, leading to major course changes over time. Another wild card: jets of dust and gas streaming off the comet as it heats up near the sun.
“We don’t really know exactly how much they are pushing this comet around,” Chodas said.
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.
