Comet 3I/ATLAS is the third known object from outside our solar system to be discovered passing through our celestial neighborhood. Found in July 2025 by NASA’s ATLAS survey telescope, this comet originates from another star system and was ejected into interstellar space.
Astronomers have categorized it as an interstellar comet due to its hyperbolic shape of orbital path. The comet will not pose a threat to Earth and will remain far away, with the closest approach being about 170 million miles (270 million kilometers) away from our planet.
Comet 3I/ATLAS is currently on course to pass behind Mars in late October and venture past Jupiter by March 2026. NASA’s James Webb Space Telescope has observed it, providing insights into its size and physical properties. The comet’s diameter was estimated to be between 1,444 feet (440 meters) and 3.5 miles (5.6 kilometers).
Astronomers have been studying the comet using various space telescopes, including Hubble, Webb, and SPHEREx. These observations will allow them to track its journey through our solar system.
The discovery of Comet 3I/ATLAS has shed light on interstellar objects and their origins in other star systems. It is expected to be visible to ground-based telescopes until September 2025, after which it will pass too close to the Sun to observe.
Source: https://science.nasa.gov/solar-system/comets/3i-atlas