The ‘comet of the year’ is coming soon. Here’s how to see it.
The comet, which will be visible to the naked eye, orbits the sun roughly once every 80,000 years—the last time it passed Earth humans were just migrating out of Africa.
On Saturday, turn your eyes to the sky for a glimpse of the comet C/2023 A3 (Tsuchinshan-ATLAS), a rare celestial passerby that many astronomers are hailing as the comet of the century.
The comet’s closest pass to the Earth will occur on October 12, after which it will likely grace the southwestern sky just after sunset in the northern hemisphere. It will show up a little bit earlier each night until fainting entirely over the next few weeks.
While Earth does see its fair share of comets come and go, what makes this instance incredibly unique is how apparent C/2023 A3 will be in the sky.
“Most comets don't normally get bright enough for someone to see with the naked eye,” says Erika Gibb, a professor of physics and astronomy at the University of Missouri - St. Louis. It’s why NEOWISE and Hale-Bopp are so famous—their intense brightness allowed them to become some of the most viewed celestial events ever.
Will comet A3 meet high expectations?
Astronomers theorize C/2023 A3 orbits the sun about once every 80,000 years, making the last time this comet appeared around the same period when humans were expanding to North Africa and Asia. It would be another 40,000 years after this comet last appeared that neanderthals went extinct.
For curious observers, getting a heads-up on the comet’s path is easy enough with online resources to help track a celestial object’s movement, but viewing the event may be a different story. There isn’t any guarantee that C/2023 A3 will be bright enough to meet such impressive expectations.
How bright a comet is depends on a collection of uncontrollable factors, such as how close the object gets to the sun, how close it gets to the Earth, its size, and how much gas and dust it produces, says Gibb. Because the universe is a chaotic place, and no two comets are alike, these conditions are not always set in stone.
Although C/2023 A3 will certainly be visible to the naked eye, it remains to be seen if its brightness overtakes the record of any previous naked-eye comet.These cautions aside, avid space enthusiasts shouldn’t blow away their chance to send off this unearthly visitor.
How to see comet A3
Depending on your location and the amount of light pollution nearby, it may be worth heading somewhere dark enough to view C/2023 A3 unfettered by the glow of a bustling city. Don’t know where to go to find a good spot? Using online light pollution maps can give you a better clue.
While not strictly necessary, watching the skies with binoculars or a small telescope may also enhance the experience, says Gibb, especially if viewers want to see the comet’s very dusty 15 degree tail. By the end of October, It will eventually become too faint to see with the naked eye.
A3’s arrival is a great opportunity for science, too. One of the biggest challenges facing current comet research is that many of the ideal observatories or scientific instruments scientists might use to study these objects oftentimes aren't already in a location a comet will be passing through.
“We've got these beautiful comets that come through and we can't always observe and study all of them, just because of where they are in the sky,” says Gibb.
Partly because this comet’s arrival has been so prominent, some researchers have already used its flyby to make new observations.
Once out of Earth’s reach, comet C/2023 A3 will probably head back to the outer part of the solar system, leaving our quaint little cosmic neighborhood behind.
It won’t be back in our lifetimes, but as it restarts it’s 80,000-year crusade, hopefully we’re still here to wave hello again.
