Dark matter composition research - Nonbaryon matter

The Big-bang model makes it possible to calculate the number of baryons in the Universe, i.e. the number of helium 4 and hydrogen atoms, formed at the time of the primary nucleosynthesis. The astronomers calculated that baryon matter amount for approximately 4% of the critical density. However, to explain the flat geometry of the Universe, the Universe's total matter must be of 30% of the critical density (the remaining 70% being dark energy). 26% of the critical density is then missing. Those 26% would be constituted of other particles that baryons.

Website navigation:
Introduction First observational evidences The galactic rotation problem
Dark matter within galaxies Dark matter between galaxies Dark matter Composition
Baryonic Nonbaryonic Neutrino WIMP String theory