[aerohead]

In 1937,Fritz Zwicky,at Cal Tech,first published about 'dark matter',working with the Virial Theorem of Rudolf Clausius,from 1870.Kinetic energy to potential energy was too far off,requiring a missing mass/hidden mass to explain it.
In 1970,Vera Rubin,observing galactic rotation and steller orbital velocities found discrepancies which suggested the necessity of missing mass to explain it.
Visible searches yielded nothing.Radio astronomy yielded nothing.Infrared spectroscopy yielded nothing.The Hubble Space Telescope has allowed for Cosmic,gravitational lensing and has detected hundreds of regions of dark matter,of which maps have been generated.
Stars,dust,and gas can not account for this mass.
A theory of Modified Newtonian Dynamics (MOND) was proposed.However,the observation of 'Bullet Clusters' violated the MOND theory,a key piece of evidence that Newtonian Physics and Gravity is right on,as of 2013.
Electrons and protons couldn't explain the mass.Those can be detected.
Dark energy is known by it's gravitational effects and the expansion of the universe.It's density doesn't change.As the universe expands there's more of it.Electrons and protons can be detected,they don't explain dark energy.