Tag Info

New answers tagged

4

The cosmological constant of classical General Relativity and the vacuum (or zero-point) energy are closely related. The cosmological constant is simply a constant term $\Lambda$ in the Lagrangian density for the Einstein-Hilbert action and may be interpreted as an energy density permeating all space. In quantum field theory, one finds that the vacuum can, ...


1

Nobody knows. There are multiple explanations for dark energy that haven't been eliminated. One of the explanations that hasn't been eliminated is zero point energy: http://arxiv.org/abs/1205.3365. Another possible explanation is that the alleged expansion is actually a result of neglecting the effects of inhomogeneities on averaging: ...


3

I would say the sign of the cosmological constant would certainly play a factor in determining singularity behaviour of the universe. This can be seen from Raychaudhuri’s equation, which is precisely obtained from Einstein’s field equations, and is given by: $$\dot{\theta} + \frac{1}{3} \theta^2 + \sigma_{uv}\sigma^{uv} - \omega_{uv} \omega^{uv} + ...


-2

Singularities are very likely impossible to create in the real universe. In other words, as a singularity gets close to forming, the incoming random GR waves and other energy will rip the formation apart, keeping it in a state of almost singularity. As an example, all Black Holes spin in the real world. The size of the singularity in a spinning Kerr ...


1

A singularity involves an infinite amount of negative potential energy in a localized volume. A nonzero cosmological constant would only yield a finite amount of positive energy in a localized volume. So the cosmological constant might slow down the rate of singularity production, but it won't stop it.



Top 50 recent answers are included