Astrophysics (Index)About

baryonic matter

(ordinary matter made up of protons and neutrons)

The phrase baryonic matter is used in astrophysics (especially, cosmology) for ordinary matter, in particular, not dark matter, and is often used in discussions of dark matter as well as statements of how much of such ordinary matter is in the observable universe or some portion of it (such as a particular galaxy cluster or galaxy). The phrase suggests it is matter made up of baryons (protons and neutrons), which would not include electrons, but by mass, the difference is small, on the order of a tenth of a percent. In addition to dark matter, matter that is definitely not baryonic matter (non-baryonic matter or nonbaryonic matter) includes neutrinos, and other things that are not baryonic matter include fundamental (non-composite) bosons, such as photons, and black holes (though whether a black hole qualifies as matter perhaps depends upon the issue you are discussing).

(physics,particles,dark matter)
Further reading:

Referenced by pages:
carbon (C)
dark matter
gas fraction
mass ratio (μ)
Tully-Fisher relation (TFR)