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This imbalance has to be exceptionally small, on the order of 1 in every 1 630 000 000 (≈ 2 × 10 9) particles a small fraction of a second after the Big Bang. [4] After most of the matter and antimatter was annihilated, what remained was all the baryonic matter in the current universe, along with a much greater number of bosons.
Neither the standard model of particle physics nor the theory of general relativity provides a known explanation for why this should be so, and it is a natural assumption that the universe is neutral with all conserved charges. [3] The Big Bang should have produced equal amounts of matter and antimatter. Since this does not seem to have been ...
The local geometry of the universe is determined by whether the relative density Ω is less than, equal to or greater than 1. From top to bottom: a spherical universe with greater than critical density (Ω>1, k>0); a hyperbolic, underdense universe (Ω<1, k<0); and a flat universe with exactly the critical density (Ω=1, k=0).
All the particles that make up the matter around us, such electrons and protons, have antimatter versions which are nearly identical, but with mirrored properties such as the opposite electric charge.
This maximal radiation density corresponds to about 1.2 × 10 17 eV/m 3 = 2.1 × 10 −19 kg/m 3, which is much greater than the observed value of 4.7 × 10 −31 kg/m 3. [4] So the sky is about five hundred billion times darker than it would be if the universe was neither expanding nor too young to have reached equilibrium yet.
In the widely accepted ΛCDM cosmological model, dark matter accounts for about 25.8% ± 1.1% of the mass and energy in the universe while about 69.2% ± 1.2% is dark energy, a mysterious form of energy responsible for the acceleration of the expansion of the universe. [17] Ordinary ('baryonic') matter therefore composes only 4.84% ± 0.1% of ...
Under current theory, the Big Bang explosion that initiated the universe should have produced equal amounts of matter and antimatter. This, however, does not seem to be the case.
[1] The lepton and baryon asymmetries affect the much better understood Big Bang nucleosynthesis at later times, during which light atomic nuclei began to form. Successful synthesis of the light elements requires that there be an imbalance in the number of baryons and antibaryons to one part in a billion when the universe is a few minutes old. [2]