A rare cosmic event unfolded recently as a coronal mass ejection from the Sun intersected with the interstellar object known as 3I/ATLAS. This object, first identified on July 1, 2025, by the ATLAS survey in Chile, is only the third known interstellar object to pass through our solar system. The collision occurred following 3I/ATLAS‘s closest approach to the Sun, known as perihelion, on October 29, 2025. Scientists are now eager to analyze the resulting data to understand the implications of this unprecedented encounter.
The significance of this event extends beyond a mere celestial spectacle. As the Sun’s explosive plasma cloud struck 3I/ATLAS, researchers anticipated critical insights into the object’s composition, density, and origin. The interaction may produce observable changes, such as a transformation in the shape of its coma, a tail of gas and dust that typically surrounds comets. The scientific community views this as a unique opportunity to gather valuable data about a body that originates from a distant star system.
In comparison, the last notable interaction between solar material and a small celestial body occurred in April 2007, when an asteroid from within our solar system experienced a similar event. Observations from NASA’s STEREO A spacecraft revealed that solar material temporarily disrupted the asteroid’s tail, but it quickly reformed. In contrast, 3I/ATLAS presents a more complex case. This object is significantly larger and heavier, weighing approximately 33 billion tons and featuring a nucleus that spans between 440 meters and 5.6 kilometers in width.
Recent observations from the James Webb Space Telescope and the Hubble Space Telescope have confirmed that 3I/ATLAS is an active comet, albeit one with an unusual composition, particularly rich in nickel. This raises intriguing questions about how it will respond to the solar forces at play. Will it withstand the blast, or will it lose part of its outer layers in a dramatic display?
As the object continues its trajectory, it is expected to approach Mars shortly. This proximity will allow for enhanced observational opportunities from more powerful telescopes. On November 16, the Virtual Telescope Project will stream live views of 3I/ATLAS, providing astronomers with critical data that could help confirm its identity.
The scientific community is also grappling with an alternative theory regarding the nature of 3I/ATLAS. Prominent astronomer Avi Loeb has proposed that the object could potentially be an alien craft, based on its extraordinary speed of 137,000 MPH and its peculiar shape, which includes jets, referred to as “anti-tails,” pointing towards the Sun. While this theory has generated intrigue, NASA is cautious, emphasizing natural explanations.
Recent findings from the MeerKAT radio telescope in South Africa have added weight to the conventional view. Observations detected faint radio signals that suggest the presence of hydroxyl radicals (OH), a chemical signature indicative of water vapour. This outgassing process occurs as the icy components of the comet evaporate under solar heat.
As the dust settles from the solar blast, the astronomical community is poised for critical revelations. Will the data emerging from this cosmic encounter confirm the natural composition of 3I/ATLAS, as suggested by the hydroxyl detection, or will it unveil anomalies that sustain the debate about its extraterrestrial origins? The next phase of analysis is set to provide answers, igniting further curiosity about this extraordinary celestial visitor.
