Where does the original singularity get its energy from?
Ohh very good questionPeroK said:You mean how does a universe emerge from nothing? Good question!
I think that some future theory, by improving a current theory, will provide the answerPeroK said:There are some speculative theories, but it may be a question too far for science to answer.
Do you think that the singularity is an "un-physical" object ?Ibix said:The point about a singularity is that it's a place and/or time we can't extend our models through. So we don't really know.
Where they came from ? ( the singularities e.g in the centre of a black hole and the Big Bang )Ibix said:Singularities are almost certainly problems with the theory, though, so if we ever work out a quantum theory of gravity we might be able to eliminate the singularities and get an answer. But at the moment we don't know.
I don't think you can define things like volume of a singularity in any particularly meaningful way. I think the expectation of more or less everyone is that they aren't anything at all, just the maths' way of saying there's something wrong with the model and a more advanced theory will eliminate them (we hope).Bosko said:Do you think that singularity is "un-physical" object ?
Meaning it have zero volume, so any mass will cause infinite density and so on.
There's something missing from the model. Most likely it's some quantum nature in spacetime (or whatever replaces spacetime in the correct theory) that becomes important when the curvature reaches some very small length scale. But who knows?Bosko said:Where they came from ?
Just in case you are not aware of it, the current model of cosmology, the Big Bang Theory, does not include a singularity. Rather, it describes the universe starting at the end of the inflation period (itself not a proven fact but almost certainly true).Arasvo said:Where does the original singularity get its energy from?
I would disagree with the "almost certainly true" part.phinds said:Just in case you are not aware of it, the current model of cosmology, the Big Bang Theory, does not include a singularity. Rather, it describes the universe starting at the end of the inflation period (itself not a proven fact but almost certainly true).
The likelihood that it is true are much lower than "almost certainly". See, e.g. (from here):phinds said:Do you have a citation that it is true or are you saying you think it is unlikely to BE true?
many physicists, mathematicians, and philosophers of science have voiced criticisms, claiming untestable predictions and a lack of serious empirical support. In 1999, John Earman and Jesús Mosterín published a thorough critical review of inflationary cosmology, concluding,
"we do not think that there are, as yet, good grounds for admitting any of the models of inflation into the standard core of cosmology."
As pointed out by Roger Penrose from 1986 on, in order to work, inflation requires extremely specific initial conditions of its own, so that the problem (or pseudo-problem) of initial conditions is not solved:
"There is something fundamentally misconceived about trying to explain the uniformity of the early universe as resulting from a thermalization process. ... For, if the thermalization is actually doing anything ... then it represents a definite increasing of the entropy. Thus, the universe would have been even more special before the thermalization than after."
The problem of specific or "fine-tuned" initial conditions would not have been solved; it would have gotten worse. At a conference in 2015, Penrose said that
"inflation isn't falsifiable, it's falsified. ... BICEP did a wonderful service by bringing all the Inflation-ists out of their shell, and giving them a black eye."
A recurrent criticism of inflation is that the invoked inflaton field does not correspond to any known physical field, and that its potential energy curve seems to be an ad hoc contrivance to accommodate almost any data obtainable. Paul Steinhardt, one of the founding fathers of inflationary cosmology, has recently become one of its sharpest critics. He calls 'bad inflation' a period of accelerated expansion whose outcome conflicts with observations, and 'good inflation' one compatible with them:
"Not only is bad inflation more likely than good inflation, but no inflation is more likely than either ... Roger Penrose considered all the possible configurations of the inflaton and gravitational fields. Some of these configurations lead to inflation ... Other configurations lead to a uniform, flat universe directly – without inflation. Obtaining a flat universe is unlikely overall. Penrose's shocking conclusion, though, was that obtaining a flat universe without inflation is much more likely than with inflation – by a factor of 10 to the googol[j] power!"
Together with Anna Ijjas and Abraham Loeb, he wrote articles claiming that the inflationary paradigm is in trouble in view of the data from the Planck satellite.