A space rock that is possibly older than the Sun itself zipped past Earth in December 2025, and an Oxford PhD student who had just submitted his thesis a week earlier was the one who worked out how old it really is. The object, called 3I/ATLAS, is only the third interstellar visitor ever confirmed entering our solar system, and going by the numbers, it may be carrying material from a star system that formed roughly 7 billion years ago, well before our own Sun switched on.
