There’s an exciting interstellar comet speeding through our solar system called 3I/ATLAS. Recent research suggests it might be about 3 billion years older than our solar neighborhood. If this is true, it could be the oldest comet we’ve ever spotted. As it heads closer to the sun, it might even develop a long, beautiful tail.
3I/ATLAS is moving toward the sun at a staggering speed of over 130,000 mph (210,000 km/h). When it reaches its closest point, or perihelion, in late October, it will start its journey back out of the solar system, likely never to return. Discovered on July 1, 2023, it was confirmed to be an interstellar object by NASA almost immediately. Since then, astronomers have been eager to learn everything they can about it.
A study released shortly after its discovery used advanced computer modeling to trace where 3I/ATLAS comes from. Researchers believe it likely originated from the Milky Way’s thick disk, a region of ancient stars above and below our galaxy’s main disk. Most stars in this area are billions of years old, making it plausible that 3I/ATLAS is too. According to Matthew Hopkins, the study’s lead author, “Our method suggests it’s very likely the oldest comet we’ve seen.” However, these findings aren’t yet peer-reviewed, so further observations are essential.
Hopkins developed a model to predict the origins of interstellar objects using data from the European Space Agency’s Gaia space observatory. He had recently completed his doctoral thesis when the discovery occurred—a perfect opportunity to test his theories.
This isn’t the first interstellar object we’ve found. Two others include ‘Oumuamua, an asteroid discovered in 2017, and Comet Borisov, spotted in 2019. Both traveled toward the sun directly, hinting they came from the main disk of the galaxy. 3I/ATLAS, however, is on a different path, coming in sideways, suggesting a unique origin. Chris Lintott, an astronomer at the University of Oxford, noted that there’s a two-thirds chance 3I/ATLAS is older than our solar system, having drifted through space for billions of years.
As we gather more data on 3I/ATLAS, researchers will refine their models to learn even more about its origins. However, pinpointing it to a specific star system might not be possible. Aster Taylor, a graduate student not involved in the study, pointed out that such precision may be out of reach.
Not only is the origin of 3I/ATLAS captivating, but understanding it could also predict how it will behave when it swings close to the sun. Experts believe this comet might contain a lot of water ice. If that’s the case, as it nears the sun, the heat could cause it to develop a stunning, long tail. The cloud of ice and gas surrounding it, called a coma, may also expand, making it shine even brighter against the night sky.
However, seeing 3I/ATLAS might not be straightforward. It won’t be visible to the naked eye; a good telescope or binoculars will be necessary. The best viewing times are expected to be in late 2025 and early 2026. As it approaches, we can anticipate a spectacular display in the sky.
The study on 3I/ATLAS adds a fascinating chapter to our understanding of the universe. As we unlock its secrets, we may learn more about the origins of comets and, perhaps, even our own solar system.
