How Fast Is Gamma Ray Photon?

Gamma rays — the highest-energy photons in the electromagnetic spectrum — travel at exactly light speed. Each photon carries millions of times more energy than visible light. Gamma-ray bursts are the most energetic events in the universe, briefly outshining entire galaxies.

Gamma-ray bursts are the most energetic events in the universe — single bursts can briefly outshine entire galaxies.

• A single gamma photon can outshine a galaxy briefly
• Wavelengths shorter than an atomic nucleus