- #1
KurtLudwig
Gold Member
- 144
- 30
Dark energy density at this time is a constant and our universe is expanding (accelerating). This is expected to continue indefinitely. What would happen, if for some unknown reason, dark energy density started to decrease? If over time, in billion of years or longer, dark energy density decreased greatly, would the universe start to contract? There are Friedmann equations relating the Hubble constant H, first and second derivatives of a scale factor a, dark energy density and pressure and G. The scale factor a is a function of time. At what point would the universe neither expand or contract? At that time, gravity and dark energy are balanced. By how much would the dark energy density have to decrease for the universe to contract?