A mystery interstellar object discovered last week is likely to be the oldest comet ever seen—possibly predating our solar system by more than 3 billion years, researchers say.

However, new research has shown this potentially "water ice-rich" visitor could be even more extraordinary than initially believed. 3I/ATLAS could be around 3 billion years older than our 4.5 billion-year-old solar system and thus any comet ever before observed.

Astronomers tracking an interstellar object flying through the solar system think it comes from a star at least 8 billion years old, almost twice the age of our sun