In Particle Physics everything is represented by a subatomic particle.
There are two classes of particles. Matter and Energy officially called Fermions and Bosons

The Four Elemental Forces of the universe are thus Bosons too.

Electromagnetic Force: AKA Light : Officially called The Photon
The Strong Force: The energy that binds atoms (Where Fusion and Fission come in the game) officially called The Gluon.
The Weak Force: (The energy of radioactive decay that creates radioactive energy from elements like Uranium and Plutonium) Officially called the "W" Boson and the "Z" Boson
The Gravitational Force: Officially called The Graviton

For Example:
An Electron is a Fermion. When it lowers it's orbit around it's atom (like the shuttle losing speed to go into a lower orbit) it must bleed off energy. That energy leaving the Electron is called a Photon.

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