The discussion centers on the nature of black holes, specifically addressing the misconception of a "core" within them. Participants clarify that, according to classical general relativity, a Schwarzschild black hole is a vacuum solution with no matter present, and the singularity is more a temporal event than a spatial location. The conversation also touches on the philosophical implications of space and time, as well as the origins of the universe, referencing inflationary models as a potential explanation for the conditions preceding the Big Bang.
PREREQUISITESAstronomers, physicists, cosmologists, and anyone interested in the theoretical foundations of black holes and the universe's origins.
There is no such thing in classical general relativity, but there could be in the quantum theory. Seempolo said:I am wondering if there is some type of matter in the core of the Black Hole. Is it possible to compute the distance from the surface of the Black Hole Core to the Event Horizon? Oh that would be fun to calculate.
While true, I did not see a real point in bringing it up in a B-level thread. I think that words such as "could be" are too easily dropped for "is" by laymen when passing on this type of information.Demystifier said:There is no such thing in classical general relativity, but there could be in the quantum theory. See
https://arxiv.org/abs/1505.04088
You are right, this is not appropriate for a B-level thread. But still, someone reading it may find it interesting.Orodruin said:While true, I did not see a real point in bringing it up in a B-level thread. I think that words such as "could be" are too easily dropped for "is" by laymen when passing on this type of information.
mpolo said:@Orodruin So what is inside of a Black Hole if there is no core matter? I was under the impression that know one really knows what is underneath the event horizon. If know one really knows what is in there then there is a possibility that it could be made up of some strange type of ultra dense matter. At any rate for discussion sake let's just say there is a sphere of some type of matter. I think it would be fun to take a guess at the density and mass of the sphere mathematically speaking and then calculate the distance from that sphere which is most likely rotating rapidly to the event horizon. That would really be fun to put into a computer program.
No. Regardless of what you might read in popular literature, the Big Bang was not an explosion in the usual sense of the word.mpolo said:When the Big Bang happened was that the result of a Black Hole that expanded or exploded?
No, it is not the radius, at least not in the sense that you would recognise it. If you look at the Schwarzschild solution inside the black hole, it is actually a time coordinate. Regardless of that, the definition of the r coordinate in the Schwarzschild solution is that the area of the corresponding sphere in the spherically symmetric solution should be ##4\pi r^2##. Note that this does not mean that this sphere has a "radius" ##r##, since it is a hypersurface in 4-dimensional curved space-time.mpolo said:What causes r which I assume is the radius to be zero?
This nomenclature is a bit toxic. Physics deals with observations and describing them. What is subjectively "real" is a matter of philosophy.mpolo said:If space can expand or bend does that not imply that space is a real thing?
The total energy of the universe is not very well defined in GR and if you manage to define it it will not be conserved in an expanding universe. One of the more popular theories about what happened before the hot big bang is inflationary models. Such models leave the universe completely empty, spatially flat, and cold apart from the presence of an inflaton field that by decaying to matter and radiation reheats the universe.mpolo said:So, okay then space expands then where did all the matter and energy come from in the Big Bang.