Zooites at the Higgs Hunters project flagged this particular image as interesting, because, despite virtually no particle tracks appearing, loads of activity is visible in the muon detector (the outermost ring of the image).

Scientist Andy Haas explains exactly what’s going on here, and is it ever cool:

“This is a fun event. What has happened is that a very energetic cosmic ray (muon) has showered in the atmosphere or rock above ATLAS creating hundreds of lower-energy muons traveling in the same direction at the same time. You’ve found a particle from outer-space (probably a supernova!), whose energy is greater than we can create at the LHC!”

Andy also gave us a little bonus:

“I’ve attached a zoomed-out slice view, where I’ve also drawn the short muon “segments” found. (They usually don’t make full tracks since they don’t line up with the proton collision point.)”

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