4 ms·
>Dark energy is known to make up 70% of the mass-energy of the universe, whereas black holes are a mere fraction of the ordinary matter, which constitutes less
by adam_d 4y ago
>Dark energy is known to make up 70% of the mass-energy of the universe, whereas black holes are a mere fraction of the ordinary matter, which constitutes less than 5% of the universe.
Is there some cosmological constraint that says dark energy compressed into a small volume would exhibit gravitational pull and therefore contribute to our measurements of black hole masses? If not then it feels like this is a weak counterargument that makes a pretty big assumption that dark energy must have the same mass-energy equivalence behaviour as regular energy from a general relativity perspective. If black holes somehow are the origin of dark energy, then surely this is driven by physics at energies far beyond our understanding from either particle physics or cosmology. In that case aren't basically all bets off in terms of what you'd expect to observe in terms of apparent black hole masses?
- deleted 4y ago[deleted]
- cowl 4y agoWell the whole idea is to "make it work" under the constrains of our current understanding (General Relativity). After all , all that Dark Energy is by definition is something that is Contrasting the Gravity as described by general Relativity. If we remove that fact than it doesn't need to be reconciled with anything really. Saying that it is a type of energy that doesn't behave according to general Relativity, you need to solve a much bigger problem, find the Substitute of General Relativity that would work for all cases and in that scenario maybe even Gravity is different and you don't even need Dark Energy.
- jdmichal 4y agoAre there MOND theories that attempt to account for dark energy too? Or only dark matter?
- mr_mitm 4y agoNot that I'm aware, but there are modified GR theories. In classical GR, the equations can be derived by applying the principle of least action with the Ricci scalar R being the Langrangian. People are studying what happens if you assume the Lagrangian is a function of R, like R^n or so. It doesn't have the same stigma as MoND, but it's also not that popular. It's also very hard to test for. https://en.wikipedia.org/wiki/F(R)_gravity https://en.wikipedia.org/wiki/F(R)_gravity
- josu 4y ago>Is there some cosmological constraint that says dark energy compressed into a small volume would exhibit gravitational pull and therefore contribute to our measurements of black hole masses? [chatGPT]> There is currently no evidence to suggest that dark energy can be compressed into a small volume and exhibit a gravitational pull in the same way that ordinary matter does. Dark energy is thought to be a property of the vacuum of space itself, and its effect on the universe is driven by its negative pressure, which causes the universe's expansion to accelerate. Black hole masses are measured by observing their gravitational effects on surrounding matter and other astronomical objects. The mass of a black hole can be estimated by measuring the velocity of nearby stars or gas clouds and using the laws of gravity to infer the mass of the object producing the gravitational field. These measurements are based on our current understanding of gravity and are not affected by the presence or absence of dark energy. However, it is worth noting that the properties of dark energy are still not fully understood, and there may be some new discoveries or developments in our understanding of gravity that could change our current understanding of these phenomena. Nonetheless, as of now, there is no evidence to suggest that dark energy can contribute to our measurements of black hole masses through its gravitational effects.