A comet that likely has never been viewed by modern humans, and was last visible from Earth at the time of the Neanderthals, will come in its closest path by our planet on Saturday, and you may be able to see it with your naked eye for several weeks in a row.
It's been named C/2023 A3 Tsuchinshan-ATLAS, and it was simultaneously discovered for the first time last year by China's Tsuchinshan Observatory and an Asteroid Terrestrial-impact Last Alert System, or ATLAS, telescope in South Africa (hence its name). As CNN reports, the comet reached perihelion, or its closest orbit point to the sun, on September 27 while it was visible only in the Southern Hemisphere. And now, it's expected to be visible from the Northern Hemisphere just after sunset from mid-October to early November.
On Saturday, C/2023 A3 Tsuchinshan-ATLAS will come within 44 million miles of Earth, and it should be readily visble with a long tail at twilight.
"It’s not going to zing across the sky like a meteor. It will just appear to hang there, and it will slowly change position from night to night," says Bill Cooke, lead of NASA’s Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama, speaking to CNN. "If you can see (the comet) with your unaided eye, (using) the binoculars will knock your socks off."
The comet comes from the Oort Cloud, a collection of comets that is only barely bound by gravity to our sun — and astronomers were unsure whether the comet would survive this trip past the sun, or perhaps break apart this time. But its ice, rocks, and frozen gases appear to be staying intact.
In San Francisco, it may be too cloudy Saturday evening to see the comet — which you should look for in the western sky. A live feed is being broadcast on YouTube by the Virtual Telescope Project, which looks like it will start Saturday morning Pacific Time.
By Sunday, though, we may be able to get a glimpse if skies clear — and those in other parts of the Bay Area and elsewhere in the US will likely start posting photos if they spot it Saturday.
And you should try to see it! As astronomer Dr. Teddy Kareta, a postdoctoral associate at Lowell Observatory in Flagstaff, Arizona, tells CNN, comets this bright and visible without a telescope don't come along often.
"For many people, and especially children, seeing a bright comet in the night sky is a beautiful and life-changing experience,” Kareta tells CNN. "Even if every couple of years a comet might be barely bright enough to be seen with your naked eye, comets that have a potential to be easily visible to many are rare. If you can try to see it, you should — and you should take whoever you can with you so they can experience it too."
The Bay Area did get to see Comet NEOWISE in the pandemic summer of 2020, and in December 2021, we had a flyby from Comet Leonard, which also had never been seen humans before, and likely won't be again.
Photo by cafuego/Wikimedia