Astronomers Uncover Secrets of 3I/ATLAS, Third Interstellar Object

On July 1, 2023, the Asteroid Terrestrial-impact Last Alert System (ATLAS) made a groundbreaking discovery by detecting what was initially thought to be an asteroid. As further calculations revealed its true nature, astronomers confirmed that it is an interstellar object, marking it as only the third such visitor detected from beyond our solar system. Dubbed 3I/ATLAS, this celestial body has sparked intense interest among scientists eager to gather insights and data despite challenges presented by its surrounding coma—a cloud of gas and dust obscuring its nucleus.

Characteristics of 3I/ATLAS

One of the first significant findings regarding 3I/ATLAS is its extraordinary speed. According to David Jewitt, an astronomer and professor at UCLA, this object is traveling at approximately 60 kilometers per second, faster than the escape velocity from the solar system. “It’s going so fast that the gravity of the sun cannot hold it back,” Jewitt explained, suggesting that this object could potentially be the oldest item ever to pass through our solar system.

Further analysis revealed that 3I/ATLAS is not an asteroid as initially believed, but rather a comet. Comets are primarily composed of frozen gases, rocks, and dust, and as they approach the sun, solar radiation heats these materials, creating a coma and tail that are characteristic of comets. While there was some speculation about the object’s origin, Jewitt and fellow astronomer James Wray from the Georgia Institute of Technology have dismissed the notion that it is alien technology. “It’s producing the types of gases that we see comets produce,” Wray noted, emphasizing its comet-like behavior.

Intriguing Observations and Future Prospects

One notable difference between 3I/ATLAS and other known comets lies in its light polarization. Wray explained that the light emitted from 3I/ATLAS behaves differently than that of other comets, appearing in a single direction rather than scattering. This anomaly may suggest unique characteristics regarding the particles that have detached from its nucleus.

The composition of 3I/ATLAS has also raised questions among researchers. Data from both the James Webb Space Telescope and SphereX indicate a high abundance of carbon dioxide compared to solar system comets. “We don’t actually know for sure if it’s unusual for interstellar objects, because this is the first one we’ve been able to measure it for,” Wray stated. The object contains other materials, including carbon monoxide and water ice. Initially estimated to be tens of kilometers wide, further observations have suggested that the nucleus measures only about 2.8 meters across, although its precise shape remains a mystery due to the obscuring coma.

The discovery of 3I/ATLAS follows two previous interstellar visitors: the first, 1I/Oumuamua, identified in 2017, and the second, 2I/Borisov, discovered in 2019. According to Jewitt, recent calculations indicate that numerous interstellar visitors may cross the solar system. “The best estimate of the density is one of those guys every 10 cubic astronomical units of space,” he explained, implying that thousands of such objects could be present at any given time.

The addition of the Vera C. Rubin telescope in Chile, which scans the sky every few days, is expected to enhance the detection of interstellar bodies. Jewitt noted that this innovation could lead to the discovery of many more interlopers and allow for extended observation periods.

As for 3I/ATLAS, it is anticipated to disappear from view as it moves into the sun’s glare in the coming weeks. However, it will reappear in December 2023, providing astronomers with approximately a year to study it as it exits the solar system. Jewitt expressed optimism about gathering more data during this time, especially since 3I/ATLAS will not pass too closely to the sun.

Wray highlighted an exciting aspect of the upcoming observations, noting that the object will come significantly closer to Mars than Earth. The Mars Reconnaissance Orbiter is expected to capture images of 3I/ATLAS with three times the resolution of the Hubble Space Telescope during its flyby on October 3, 2023. This opportunity could yield valuable insights into this remarkable interstellar visitor before it continues its journey beyond our solar system.