Atlas comet: When's your best chance to spot comet that may never return

PHILADELPHIA - An icy comet that will take 80,000 years to return – if it survives the trip – is streaking across the sky this October. 

Comet Tsuchinshan-Atlas, which was discovered last year and is named for the observatories in China and South Africa that spied it, made its closest pass to earth of 44 million miles over the weekend.  Astronomers say it will stay visible throughout most of the month as it slings towards Earth in the outer reaches of the solar system.

One possible complication from an otherwise perfect Wednesday night forecast is an almost equally rare Super Moon, which could make a clear night too bright to spot the comet. It's the third of four Super Moons this year, and will seem bigger and brighter than the previous two.

"Most astronomers hate the full moon because its bright light messes up observing other objects. So it’s a bit hard for us to wax poetic about it even if it’s the biggest supermoon of 2024," NASA’s Bill Cooke told the Associated Press.

Where did the comet come from?

The comet, also designated C/2023 A3, was discovered last year and is named for the observatories in China and South Africa that spied it.

It came from what’s known as the Oort Cloud well beyond Pluto. After making its closest approach about 44 million miles (71 million kilometers) of Earth, it won’t return for another 80,000 years — assuming it survives the trip.

Several comets are discovered every year, but many burn up near the sun or linger too far away to be visible without special equipment, according to Larry Denneau, a lead researcher with the Atlas telescope that helped discover the comet.

How to view the comet

Those hoping to spot the comet should venture outside about an hour after sunset on a clear night and look to the west.

The comet should be visible from both the northern and southern hemispheres.

When will the comet return? 

Astronomers say the comet could return in 80,000 years, but it's increasingly likely that due to the space rock's composition, it won't return at all. 

"Most comets have these incredibly long periods and maybe don't even come back," Drexel University Physics Professor Christina Love said.

Halley's Comet, for comparison, is considered a once in a lifetime celestial event that returns every 75 years or so.

What is a comet?

Comets are frozen leftovers from the solar system’s formation billions of years ago. They heat up as they swing toward the sun, releasing their characteristic streaming tails.

In 2023, a green comet that last visited Earth 50,000 years ago zoomed by the planet again. Other notable flybys included Neowise in 2020, and Hale-Bopp and Hyakutake in the mid to late 1990s.

The Associated Press contributed to this report