,

eV (calculated)

Force Fields

Observed Cosmic Ray

Main Source

3.7 × 103

photon

(electromagnetism)

7 × 107

(strong)

solar

9.1 × 1010 (given)

(weak)

galactic SNR

1.7 × 1015

the first knee

galactic SNR

2.4 × 1017

the second knee

galactic SNR

3.2 × 1019

the toe

extragalactic UHECR

4.4 × 1021

beyond the GZK limit

not observed

6.0 × 1023

8.3 × 1025

1.1 × 1028

Planck mass (gravity)