3I/ATLAS: The Ancient Comet from Another Star That Arrived in 2025
About 6 min readOn 1 July 2025, a telescope in Chile spotted the third visitor ever known to arrive from another star system — a comet older than the Sun, carrying water far heavier than any in our Solar System. 3I/ATLAS swung past the Sun in October 2025, past Mars, and is now heading back to the stars, never to return.