# Greisen–Zatsepin–Kuzmin limit

> theoretical upper limit on the energy of cosmic ray protons

**Wikidata**: [Q1487746](https://www.wikidata.org/wiki/Q1487746)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit)  
**Source**: https://4ort.xyz/entity/greisen-zatsepin-kuzmin-limit


## References

1. Freebase Data Dumps. 2013