On a night in 1991, a single subatomic particle hit Earth's atmosphere carrying the kinetic energy of a fastball — an invisible speck moving at 99.99999999999999999999951% of light speed. It shouldn't be possible. Decades later, an even stranger one arrived from a patch of sky where there is nothing at all.
Astrophysicist Matt O'Dowd explains how a single atomic nucleus carried the punch of a thrown baseball, and why physics says it almost shouldn't exist.
The 1991 event over Utah's Fly's Eye observatory: 3.2×10^20 electronvolts, tens of millions of times more energetic than anything the LHC can produce.
Why the OMG particle collides with the GZK limit — a theoretical ceiling on cosmic-ray energy — and what that paradox means for where these things come from.
A friendly, vivid breakdown of the numbers that make your brain hurt: how one particle can outclass every machine humanity has ever built.
In 2021 the Telescope Array caught a 244 EeV monster — the most powerful cosmic ray since 1991 — and traced its arrival to the Local Void, where almost nothing exists.
The moment the Amaterasu detection went public — and researchers admitted they had no idea what could accelerate a particle to such an impossible speed.
The unsettling twist: trace Amaterasu's trajectory backward and it points to empty space. No galaxy, no black hole, no obvious engine — just void.
A clear visual explainer of the 2023 discovery and why 'it came from nowhere' is a genuinely open problem at the edge of known physics.