Newly released images of the interstellar comet 3I/ATLAS showcase a significant jet of gas and dust directed toward the sun. This phenomenon aligns with typical comet behavior, reinforcing the object’s classification as a comet rather than an artificial spacecraft, as some have speculated.
Discovered in late June and confirmed by NASA in early July, 3I/ATLAS originates from a distant star system far beyond our own. Measuring between 3 and 7 miles (5 to 11 kilometers) wide, it is the largest interstellar object recorded to date and potentially the oldest, with a history that may stretch back billions of years, predating the sun’s formation.
The latest images were captured on August 2, 2023, by the Two-meter Twin Telescope at the Teide Observatory in the Canary Islands. They combine 159 exposures, each lasting 50 seconds, to produce a composite image. This depiction reveals the icy nucleus of 3I/ATLAS as a dark spot, surrounded by a bright glow. A distinct fan-shaped break in the glow signifies a large, high-speed jet of material—marked in purple—streaming toward the sun.
According to Miquel Serra-Ricart, an astrophysicist and chief science officer at the Teide Observatory’s Light Bridges research institution, this jet is a common feature of comets. “Jets are pointing to the sunward direction and the comet’s tail in the anti-solar direction,” Serra-Ricart explained. This behavior results from the comet heating unevenly as it approaches the sun, causing gases at vulnerable spots on its surface to erupt like geysers.
Comets are renowned for their spectacular tails of ionized gas, which can extend for hundreds of millions of miles in the opposite direction from the sun. The jets, however, are normally smaller and can indeed point toward the sun. The presence of a jet directed at our star should not be misconstrued as suspicious; it is merely a characteristic of normal cometary activity.
The jet of 3I/ATLAS could extend approximately 6,200 miles (10,000 kilometers) from its surface, primarily composed of dust particles and carbon dioxide. This composition aligns with the findings from the James Webb Space Telescope, which detected a significant gaseous plume around the comet earlier in August.
On October 3, 2023, 3I/ATLAS made a close pass by Mars and is currently approaching its perihelion, the closest point to the sun, which it will reach on October 29, 2023. While the comet is on the far side of the sun and not visible from Earth, it will re-emerge in mid-November. Astronomers anticipate this will provide a unique opportunity to observe how the comet has changed following its solar encounter, particularly regarding the growth of its jet and tail.
The ongoing observations of 3I/ATLAS underscore the fascinating complexities of interstellar objects and the importance of continued research in understanding their origins and behaviors.
