Only 4% Of The Universe Is Matter

Fact of the day: Only 4% of the universe is matter, 23% is dark matter, 73% is dark energy.

Dark matter in one of the mysteries of astrophysics and cosmology. It is very elusive stuff (I am calling it 'stuff'' because it is not technically matter) that very rarely interacts with matter, and does not emit any radiation. We only know it exists because of its gravitational effect on matter.
It was noticed when Lord Kelvin was measuring the mass of galaxies and suggested that the majority of stars may be dark bodies. The existence of dark matter being a totally different type of matter was proposed in 1932 by Jan Oort.
These scientists found that the visible mass of galaxies would not hold onto the stars on the outer edges of the galaxies as the stars velocities would be to fast, unless there was more 'undetectable' mass in the galaxies providing a gravitational pull.

Scientists are attempting to detect dark matter in underground research facilities, so the solar radiation would not interfere with experiments. The most probable theoretical particles that dark matter could consist of are WIMPs (Weakly Interacting Massive Particles) or axions.
Millions or even billions of these particles may pass through a cubic centimetre every second.


(above) Galaxies do not have enough visible mass to hold onto their outer stars.

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