Are SWAN R2 and 3I ATLAS About to Collide?

The story usually begins the same way. Someone somewhere spots a new object in the sky and within hours the internet has decided it is about to end civilisation. This time the gossip has taken a strangely cinematic turn. A comet named SWAN R2, fresh off the discovery block, is apparently hurtling straight towards another cosmic drifter, the interstellar visitor known as 3I ATLAS. Two celestial bodies on a crash course, colliding in spectacular fashion while humanity watches from below.

It is the kind of narrative that spreads with ease because it sounds dramatic enough to be true. You can almost picture the CGI already. Yet the reality is a little more mundane and a lot less explosive.

SWAN R2 is a comet from our own backyard. It came into focus in September thanks to the SWAN instrument riding on the SOHO spacecraft. Far from being an alien envoy it is a long period comet with a rather leisurely orbital cycle of about twenty two thousand years. It will drift past the Sun, swing close enough to Earth for us to catch a glimpse in October, and then vanish again into the outer dark until humanity has long forgotten what social media even was.

3I ATLAS on the other hand is the genuine outsider. It is on a hyperbolic trajectory which means it is not coming back. It entered our solar system like a passing stranger glancing at their watch and will soon be gone forever. It will never cross paths with SWAN R2 because their routes do not even come close. The idea of them colliding is as likely as you and a penguin accidentally knocking shoulders while you shop for milk.

So where does the talk of a collision come from. Mostly the usual cocktail of over enthusiastic headlines, speculative social media posts, and the human tendency to prefer the thrill of impending doom over the calmness of numbers and orbital charts. Mention the word interstellar and suddenly the imagination races to motherships and secret alien highways. Call a comet SWAN R2 and it sounds like it should have a cameo in Star Wars. The hype is almost inevitable.

The real story is quieter but no less interesting. Over the coming weeks SWAN R2 will brighten in the night sky and may even show itself to the naked eye if conditions are kind. 3I ATLAS will continue its one way journey, reminding us that now and then the galaxy does drop by to say hello. No collisions, no cosmic fireworks, just two very different kinds of travellers politely ignoring one another.

If you are tempted to believe otherwise, remember that the universe is already fascinating enough without inventing demolition derbies between passing rocks.