Imagine a foreign object, utterly unlike anything we have ever tracked, shooting through our solar system. It's moving backwards, it's surrounded by a strange sunward 'anti-tail', and it's speeding towards its closest approach to Earth just days before Christmas. To most of the world, this is interstellar object 3I/ATLAS—a confusing, yet natural, comet.
But to Harvard theoretical physicist Professor Avi Loeb, it represents something far more profound: a potential message from an advanced, extraterrestrial civilisation.
