A visitor is hurtling through the void, a silent, ancient vagabond from an alien star system, and by the end of the week, it will make its closest ever approach to Earth. This is no ordinary comet; it is 3I/ATLAS, only the third interstellar object ever confirmed, and its fleeting presence is granting astronomers an unparalleled peek at the birth of a world beyond our own. Forget everything you know about comets — this mysterious traveller is behaving in ways that defy our textbooks, from its seemingly controlled path to an unusual tail pointing in the wrong direction.
Discovered on July 1, 2025 by the NASA-funded ATLAS telescopes in Chile, this cosmic stranger has been traversing the Milky Way galaxy for billions of years. Its path through our solar system is hyperbolic, meaning it is here now, but it will soon be ejected back into the interstellar medium, never to return. This 'untainted data' — material formed in the swirling protoplanetary disc of gas and dust around a star far, far away — is the astronomical gold standard.
