Comet ATLAS C/2024 G3 falls apart after rare encounter with the Sun
Studying comets that get destroyed by the Sun tells scientists more about the origins of the solar system. Comet C/2024 G3 ATLAS lost its head after a rare close approach to the Sun in January.
Watch: Comet C/2023 A3 streaks across California sky
FILE VIDEO: A once-in-80,000-year sight made its closest approach to Earth this weekend, and a stunning video recorded in California shows Comet C/2023 A3 streaking across the night sky.
Comet C/2024 G3 has mesmerized astronomers and amateur skygazers for months as the world tried to spot the bright comet in the sky nearing its fatal encounter with the Sun.
The comet discovered last year using the Asteroid Terrestial-Impact Last Alert System, or ATLAS, is relatively rare because of how close it got to the Sun in mid-January, passing about one-third the closest distance Mercury gets to the Sun.
"That’s very close," said Dr. Qicheng Zhang, a post-doctoral astronomer at Lowell Observatory in Arizona, who studies Sun-grazer comets like Comet C/2024 G3 ATLAS.
However, the dangerous encounter with our star changed Comet C/2024 G3 ATLAS, destroying its nucleus – the "head" of the comet.
Comet 2024-G3 (Atlas) seen from the International Space Station on Jan. 11, 2025.
(Don Petit/NASA)
Photos from the Southern Hemisphere and even the International Space Station show the bright tail of the comet, which is what these space objects are known for. However, Zhang explains it’s what you don’t see in the night sky that produces the tail.
"What you're seeing is not the nucleus itself, because that's actually a really small rock. What we're seeing is all the stuff that this water vapor wind is pushing out and that creates the tail in the sky that we can actually see," Zhang said.
After its closest approach to the Sun, known as perihelion, Comet C/2024 lost its nucleus and now looks more like a "fuzzy cloud" because it’s not putting out new dust.
Comets that get this close to the Sun don’t normally come away looking the same.
On approach to the Sun, the ice from the comet turns into water vapor, which acts like jets or thrusters. Comets are small rocks held together by gravity, and these destabilizing forces allow the comet to fall apart as it heats up, which is what Zhang believes happened to Comet C/2024 G3 ATLAS.
Considered a long-period comet, Comet C/2024 G3 ATLAS took about 160,000 years to orbit the Sun, but it won’t be returning.
"This comet is not coming back because it's basically destroyed. All that's left is a cloud of dust," Zhang said.
What can we learn from Sun-grazing comets?
Even though Comet ATLAS was only discovered over a year ago, its short life wasn’t in vain. Astronomers study Sun-grazing comets because they are essentially leftovers from the solar system's formation.
Zhang said watching comets get destroyed by the Sun tells astronomers about what these leftovers are made of.
NASA's SOHO spacecraft shows C/2024 S1 ATLAS (entering from bottom right) moving toward the Sun.
(NASA)
"We're using the Sun as like a cosmic oven, or maybe a Bunsen burner, where you can toss stuff in, and then the Sun breaks it down for you," he said. "You can look at the spectrum, and you can look at images and figure out essentially what actually makes up all of the dust that's in it."
Zhang said figuring out how a comet behaves close to the Sun can tell us how the solar system evolved.
Actual Sun-grazing comets are even rarer. One of the brightest comet displays happened in 1965 when Comet Ikeya-Seki reached less than 300,000 miles from the surface of the Sun.