- #1
Rasalhague
- 1,387
- 2
The Wikipedia article on dark energy says "dark energy would need to have a strong negative pressure". In what sense can energy "have" pressure?
Is it that the value of the metric tensor field at an event, when multiplied by the cosmological constant, is a tensor in some way analogous to the stress-energy tensor, with components corresponding to energy-density, momentum density and stress? Is this effectively the stress-energy tensor of some, as yet, unidentified matter? If so, why does it play a different role in the equation to the stress-energy tensor of dark matter, which I'm guessing (rightly or wrongly) is subsumed into the regular stress-energy tensor. When Wikipedia: Dark energy says, "In the standard model of cosmology, dark energy currently accounts for 73% of the total mass-energy of the universe", what is the relationship of pressure to this figure of 73%?
Is it that the value of the metric tensor field at an event, when multiplied by the cosmological constant, is a tensor in some way analogous to the stress-energy tensor, with components corresponding to energy-density, momentum density and stress? Is this effectively the stress-energy tensor of some, as yet, unidentified matter? If so, why does it play a different role in the equation to the stress-energy tensor of dark matter, which I'm guessing (rightly or wrongly) is subsumed into the regular stress-energy tensor. When Wikipedia: Dark energy says, "In the standard model of cosmology, dark energy currently accounts for 73% of the total mass-energy of the universe", what is the relationship of pressure to this figure of 73%?