Atlas Comet: When is the best chance to spot a comet that may never return?

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

Comet Tsuchinshan-Atlas, discovered last year and named after the observatories in China and South Africa that discovered it, made its closest pass to Earth over the weekend at a distance of 44 million miles. Astronomers say it will remain visible for most of the month as it passes toward Earth in the outer reaches of the solar system.

A possible complication to an otherwise perfect forecast for Wednesday night is an almost equally rare supermoon that could make a clear night too bright to see the comet. It is the third of four supermoons this year and will appear larger and brighter than the previous two.

“Most astronomers hate the full moon because its bright light makes it difficult to observe other objects. So it's a little hard for us to wax poetic about it, even if it is the largest supermoon of 2024,” NASA's Bill Cooke told the Associated Press.

Where did the comet come from?

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

It came from the so-called Oort cloud far behind Pluto. After its closest approach to Earth is about 71 million kilometers, it will not return for another 80,000 years – assuming it survives the journey.

According to Larry Denneau, a senior researcher at the Atlas telescope that helped discover the comet, several comets are discovered each year, but many burn up near the sun or remain too far away to be visible without special equipment.

This is how you see the comet

If you want to spot the comet, you should go outside about an hour after sunset on a clear night and look west.

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

When will the comet return?

Astronomers believe the comet could return in 80,000 years, but it is becoming increasingly likely that it will not return at all due to the composition of space rocks.

“Most comets have these incredibly long periods and may not even come back,” said Christina Love, a physics professor at Drexel University.

For comparison: Halley's Comet is considered a one-time celestial event that returns approximately every 75 years.

What is a comet?

are comets frozen remnants of the formation of the solar system billions of years ago. They heat up as they swing towards the sun and let go of their characteristic tails.

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