This October, Earth will witness a visitor from the deep past: Comet C/2023 A3 Tsuchinshan-Atlas, a cosmic traveler last seen when Neanderthals and mammoths roamed the Earth. The comet, discovered just last year, will make its closest approach to our planet on October 13, and it may become one of the brightest comets visible to the naked eye in decades.

“Naked-eye-visible comets are rare enough as it is,” Gregory Brown, an astronomer at the Royal Observatory Greenwich, told The Guardian. “And this one has the potential to be amongst the brightest that we’ve seen in the last few decades.”

The comet is passing just 44 million miles from Earth — close enough to be visible but still far away so it’s safe. Stargazers have the rare opportunity to witness this icy object, one that won’t be seen again for another 80,000 years. The world, and humanity itself, may be unrecognizable by then.

From the Depths of the Oort Cloud

Comet C/2023 A3 Tsuchinshan-Atlas hails from a distant and mysterious region of our Solar System known as the Oort Cloud. This spherical shell of icy debris surrounds the Sun far beyond the orbit of Neptune, harboring remnants from the system’s formation billions of years ago. Every so often, one of these ancient objects is jostled out of place, and sent tumbling toward the inner Solar System.

Astronomers first spotted Tsuchinshan-Atlas early last year. Its orbit, calculated to stretch over 80,000 years, suggests that the last time this comet passed by Earth, the world was gripped by the Ice Age. Neanderthals, Denisovans, and early Homo sapiens lived in a landscape of towering glaciers and vast tundras. Mammoths and other megafauna roamed across northern Europe and Asia, unaware that this frozen celestial body was silently passing by.

After 80,000 years of gliding through the outer dark, Tsuchinshan-Atlas is returning, looping back toward the Sun that promises to be a fine spectacle. It’s a once-in-a-civilization sight. We honestly don’t know what Earth might look like the next time it comes around, or if humans will even be here to see it.

How to Spot the Comet

Although the comet’s closest approach is October 13, stargazers will need to time their viewings carefully. In the days leading up to and following this date, Tsuchinshan-Atlas may be too close to the Sun’s glare to spot easily. However, starting around October 9, as the comet moves out from the Sun’s blinding rays, it could become visible in the western sky just after sunset.

If you’re hoping to see it, aim your gaze westward, toward the constellation Boötes. At first, the comet may appear as a fuzzy, faint smudge to the naked eye, but even a simple pair of binoculars will bring out its glowing tail in more detail.

However, comet brightness is famously unpredictable. It’s visible already, but just how bright it will get, astronomers can’t say for sure.

For seasoned comet hunters or curious observers, Tsuchinshan-Atlas offers a chance to witness an event that connects us across time.

So, in the coming days, step outside, find a dark spot, and let your eyes adjust to the night. You might just catch a glimpse of something that links our present to an ancient, unfathomable past.