On 15th August 1991. A special camera on a mountain in Utah detected a particle so strong, that it became known as the Oh-My-God particle.
Smaller than an atomic nucleus. It had as much energy as a baseball travelling at 95 kmph.
It came from space. From outside the solar system. Outside the galaxy. A cosmic ray.
Probably a proton. Travelled so close to the speed of light, that in a race with a photon, it would take the photon 215,000 years to get 1 cm ahead of it.
And for those worried about particle accelerators, like Larger Hadron Collider, the OMG particle had over 40 million times more energy than the most what LHC can produce.
In fact, to produce a particle that powerful, you’d need a particle accelerator larger than the orbit of Mercury.
What could generate such a powerful cosmic ray?
It remains a mystery.
Tracking them down is difficult. Because they're charged, their paths are curved by the galactic magnetic field, so you can't look straight back from where they came.
Many of them even appear to come from a local halo,
But a new research has given some clues.
We have now found some cosmic ray hotspots across the sky. And intriguingly, some candidate objects are just in the right locations.
A major source can be stars in galactic centers. Those that get too close to the supermassive black hole, are ripped apart.
When a black hole eats a star, two jets of material shoot out in opposite directions, travelling close to the speed of light..