A mysterious visitor from the stars is currently challenging everything we thought we knew about interstellar wanderers. The latest data from the Hubble Space Telescope has just added a sharp and unexpected wrinkle to the unfolding story of 3I/ATLAS, an object that refuses to behave like a standard comet.
Discovered on July 1, 2025 by the Asteroid Terrestrial-impact Last Alert System in Chile, 3I/ATLAS is only the third interstellar object ever detected, following in the footsteps of 1I/'Oumuamua and 2I/Borisov. However, with a staggering velocity of 130,000 miles per hour and a nucleus estimated to be between 440 metres and 5.6 kilometres wide, it is proving to be the most complex visitor yet.
