Surprising new photos of comet 3I/ATLAS taken during last week's total lunar eclipse hint that the "interstellar visitor" may be turning bright green as it approaches the halfway point on its journey through the solar system. This unexpected transformation, if confirmed, is likely the result of the comet's increasing proximity to the sun, experts say.
3I/ATLAS is a roughly 7-mile-wide (11 kilometers) comet that was first spotted in early July, zooming toward us at more than 130,000 mph (210,000 km/h) from beyond the orbit of Jupiter. Astronomers quickly realized that the superfast object did not originate within our cosmic neighborhood, and was instead passing through on a one-way trip. It was likely ejected from a distant star system within the Milky Way and is probably much older than the solar system.
