# Changeover from deceleration to acceleration

## Main Question or Discussion Point

Did the universe changeover from deceleration to acceleration exactly after the moment when the increasing repulsive force became equal to the decreasing gravitational force?

[Would like to confirm if that would be consistent with the fact that acceleration starts when the mass density of the vacuum becomes bigger than half of mass density of matter.]

Ich
It's a constant repulsive "force", if you will, not an increasing one. Otherwise you're correct.

It's a constant repulsive "force", if you will, not an increasing one. Otherwise you're correct.
But doesn't the repulsive force of the cosmological constant increase in proportion to distance?

Ich
But doesn't the repulsive force of the cosmological constant increase in proportion to distance?
So does gravitation. I was referring to DE being constant over time, while matter gets diluted.

So does gravitation. I was referring to DE being constant over time, while matter gets diluted.
I know ;). So then I assume I can confirm my original query about the universe accelerating just after repulsive force overtakes gravitational force.

Ich
Yes. Expansion accelerates when $\Omega_{\Lambda}>\Omega_M/2$.

Chronos
Gold Member
SNAP suggests expansion began accelerating a few billion years ago. You can search for SNAP on Arxiv.

Wallace