Interstellar Object 3I/ATLAS Enters Solar System, Offering Astronomers Unique Insights
In a groundbreaking discovery, astronomers have confirmed that an object spotted traveling through our outer solar system originated from interstellar space. Named A11pl3Z, it has now officially been designated as 3I/ATLAS, with the “I” signifying its interstellar origins. Currently located between the asteroid belt and Jupiter, 3I/ATLAS is approximately 416 million miles away from the Sun, a distance that is about four and a half times greater than that between Earth and the Sun.
Speeding Through Space
This celestial visitor is not just a distant curiosity; it’s hurtling towards us at a staggering speed of approximately 130,000 miles per hour. Avi Loeb, a Harvard astronomer, humorously noted that this speed is “a thousand times over the speed limit on a highway.” Paul Chodas, director of NASA’s Center for Near Earth Object Studies, indicated that tracing back its orbit suggests it comes from the center of our galaxy, but the exact solar system it originated from remains unknown.
- This marks the third confirmed interstellar object to enter our solar system.
- The first was ‘Oumuamua in 2017, known for its elongated shape.
- The second was a comet named Borisov, which broke apart upon arrival.
A Comet in the Making?
Preliminary observations suggest that 3I/ATLAS is likely a comet, making it the second known “rogue” comet to pass through our solar neighborhood. Initially identified by a telescope in Chile as part of the Asteroid Terrestrial-impact Last Alert System (ATLAS), the object received quick verification from the International Astronomical Union’s Minor Planet Center and NASA’s Jet Propulsion Laboratory.
Following its discovery, over 100 observations from telescopes around the globe confirmed its unusual characteristics, including signs of cometary activity. Chodas emphasized, “There’s no uncertainty about its interstellar origins, as it’s moving too quickly to have originated from our solar system.”
The Mystery of its Size
The size of 3I/ATLAS remains open to debate. If it were a rocky asteroid, it would need to be about 12 miles wide to reflect the observed light. However, as a comet, determining its size is more complex due to its gaseous coma, which forms when sunlight heats the object and releases dust and gas. This coma can appear significantly larger than the solid core, complicating size estimates. For context, Borisov’s coma was nearly 100,000 miles long, which is about 14 times the size of Earth.
“You can’t infer the size of the solid object from the brightness of the coma,” Chodas remarked, indicating that further observations will be necessary for accurate measurements.
Future Observations
A silver lining in this discovery is the ample time available for astronomers to study 3I/ATLAS. Unlike ‘Oumuamua, which quickly disappeared from view, 3I/ATLAS is expected to remain observable for an extended period. According to Chodas, “It’ll be easily observable for astronomers around the world. It should be visible well into next year to large telescopes.”
NASA anticipates that 3I/ATLAS will reach its closest point to the Sun around October 30, passing at a distance of approximately 130 million miles, putting it within the orbit of Mars. This event promises to provide an unparalleled opportunity to learn more about the dynamics and characteristics of interstellar objects.