Universe  ID: 10567

How Cosmic-ray Protons Make Gamma rays

In the simplest and most common interaction, a cosmic-ray proton strikes another proton. The protons survive the collision, but their interaction creates an unstable particle — a pion — with only 14 percent the mass of a proton. In 10 millionths of a billionth of a second, the pion decays into a pair of gamma-ray photons. More complex scenarios occur when cosmic-ray protons strike nuclei containing greater numbers of particles.


Scott Wiessinger (UMBC): Lead Animator
Scott Wiessinger (UMBC): Producer
Francis Reddy (SPSYS): Writer
Please give credit for this item to:
NASA/Goddard Space Flight Center

Short URL to share this page:

Fermi Gamma-ray Space Telescope

This item is part of this series:
Astrophysics Animations

SVS >> Gamma Ray
SVS >> Astrophysics
SVS >> Universe
SVS >> Fermi
SVS >> Supernova
NASA Science >> Universe