NASA finds third interstellar comet crossing solar system

On July 3, 2025, NASA announced the discovery of an interstellar comet known as 3I/ATLAS, detected using the ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope in Rio Hurtado, Chile. The comet is located approximately 416 million miles from the sun, moving on a trajectory that suggests it originated from interstellar space. Astronomers confirmed that this comet is the third known interstellar object to pass through our solar system, following the earlier discoveries of 'Oumuamua in 2017 and comet 2I/Borisov in 2019. As the comet approaches, it is expected to make its closest approach to the sun around October 30, 2025, with predictions indicating it will be at a safe distance of at least 150 million miles away, crossing just inside the orbit of Mars. While the comet poses no threat to Earth, it will remain visible to ground-based telescopes through September 2025, allowing astronomers to investigate its physical properties. Observations from various telescopes indicated signs of cometary activity, particularly with a short tail and a faint coma, confirming its classification as a comet. The initial observations of 3I/ATLAS date back to June 14, 2025, revealing a swift-moving object that intrigued astronomers. With the ability to gain insights from interstellar bodies, astronomers hope to learn about the origins and compositions of celestial matter from other star systems. The unique characteristics of 3I/ATLAS could inform our understanding of the galaxy and potentially lead to more discoveries as sky surveys improve. In light of these discoveries, excitement surrounds further explorations into interstellar objects, especially with advancements in observational capabilities provided by new facilities such as the Vera C. Rubin Observatory. The continued monitoring of 3I/ATLAS and subsequent interstellar comets is pivotal for expanding our knowledge of celestial phenomena beyond our own solar system.