Space has intrinsic negative energy {dark energy}|. Dark energy is 70% of universe mass-energy (ordinary matter and dark matter are 30%). Perhaps, dark energy is virtual particles that have negative energy {vacuum energy} and repulse masses. Perhaps, dark energy involves new forces and interactions, such as quintessence. Perhaps, dark energy uses hidden space dimensions.
As they travel, electron, muon, and tau neutrinos, which have different masses, interconvert. Perhaps, neutrino-mass changes make dark energy, as they oscillate matter quark flavors. Dark-energy density is similar to neutrino density.
Perhaps, supernova changes or distant-particle effects cause space expansion, so there is no dark energy. Perhaps, rippling long-wavelength waves still travel after cosmic inflation and increase in intensity, expanding universe indefinitely, so there is no dark energy. Perhaps, non-linear mass interactions (backreaction) contribute to space expansion.
density
Dark energy density is 10^-26 kg/m^3. Dark-energy density variation over space is zero, because dark-energy particles do not attract each other, so space has constant dark-energy density over time and space.
When energy is negative, force is repulsive, so positive space expansion amount equals added negative energy amount, keeping dark-energy density same when universe is small or large.
space expansion
After cosmic inflation ended, 1 second after universe origin, dark energy causes universe space expansion.
internal pressure
Rubber membranes resist stretching (expansion) and compressing (contraction). Stretched rubber membranes try to contract (like gravity) and have positive (attractive) restoring force, potential energy, and internal pressure. Compressed rubber membranes try to expand (like antigravity) and have negative (repulsive) restoring force, potential energy, and internal pressure. Quantum vacuum has negative (repulsive) force that expands space, increasing negative potential energy (dark energy) by subtracting universe positive kinetic energy, and so cooling the universe. Quantum vacuum has negative internal pressure between one-third and one of mass-energy density, so repulsive antigravity is between zero and negative two times mass-energy density: M + 3 * -(M/3) = 0 and M + 3 * -M = -2*M.
universe
In early universe, dark-energy repulsion and gravitational attraction clustered matter into protogalaxy filaments. Filaments formed galaxy clusters. Galaxy clusters stopped forming six billion years ago, as space expansion made mass-energy density lower and gravity less, while dark-energy density stayed constant. Clusters allow galaxy collisions, so older galaxies have irregular shapes (while younger galaxies are spirals). Colliding galaxies increase star formation. Star formation became low six billion years ago.
Before five billion years ago, mass-energy density was higher than dark-energy density, so universe initial expansion slowed. Five billion years ago, mass-energy density became equal to dark-energy density. After five billion years ago, mass-energy density became less than dark-energy density, and universe expansion accelerated. In the future, dark energy will cause faster separation of galaxy clusters, then galaxies, then stars and planets, then molecules, and finally atoms.
heavy elements
If dark energy was stronger, filaments are fewer, clustering is less, and star formation is less, so fewer supernovas make fewer heavy elements. If dark energy was weaker, filaments are more numerous, and clustering is more, but star formation makes smaller stars, which do not supernova to make heavy elements. Universe dark-energy density maximizes heavy-element formation.
Physical Sciences>Astronomy>Universe>Cosmology>Energy
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Date Modified: 2022.0224