3I/ATLAS: A Cosmic Interstellar Visitor
The comet, first spotted on July 1 by the NASA-funded ATLAS survey telescope in Chile, is only the third known interstellar object ever observed passing through our neighborhood. It arrived from the direction of the star Sagittarius and is now cruising about 420 million miles away from Earth, the space agency reported earlier this month.
The comet poses no threat to Earth and will remain at a distance of at least 1.6 astronomical units (about 150 million miles or 240 million km). It is currently about 4.5 au (about 416 million miles or 670 million km) from the Sun. 3I/ATLAS will reach its closest approach to the Sun around Oct. 30, at a distance of 1.4 au (about 130 million miles or 210 million km) — just inside the orbit of Mars.
The interstellar comet’s size and physical properties are being investigated by astronomers around the world. 3I/ATLAS should remain visible to ground-based telescopes through September, after which it will pass too close to the Sun to observe. It is expected to reappear on the other side of the Sun by early December, allowing for renewed observations.
/ATLAS is the largest and brightest interstellar object yet, which means it could help scientists unlock clues about the formation of other star systems.
The “I” stands for “interstellar,” showing it came from beyond our solar system, and the “3” marks it as only the third type of this comet ever found.
