The Oh-My-God particle was the highest-energy cosmic ray detected so far. Its energy was estimated as (3.2±0.9)×1020 eV, or 51 J. This is 20 million times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object.
Equivalent to a 142-gram baseball travelling at about 58 mph.
Would I feel this if it hit my body?