The search for dark matter

Context

 Many physicists strongly believe that the entire visible part of the universe forms only 5% of all matter in it. They believe the rest is made up of dark matter and dark energy.

What is dark matter and why is it so elusive?

• Four fundamental forces -All interactions in the universe are a result of four fundamental forces acting on particles — strong nuclear force, weak nuclear force, electromagnetic force and gravitation.
• Particles that do not have a charge -Dark matter is made up of particles that do not have a charge — which means they do not interact through electromagnetic interactions.
• Why Dark?-These are particles that are “dark”, namely because they do not emit light, which is an electromagnetic phenomenon, and “matter” because they possess mass like normal matter and hence interact through gravity.