I shall simply have to plead ignorance on this one, but I was surprised nevertheless that I hadn't seen a competing explanation of the universe quite like this before. "How can it be that I've not heard a peep about something so ostensibly groundbreaking?" I wondered. Well, I haven't yet busied myself with reading any sort of refutation of this theory, and it's even harder yet to find follow up on the massive potential of such a description of the universe as this. As it stands, however, I can't help but predict that it was unable catch a lot of traction with cosmologists, but I'm wondering if anyone out there is/was familiar with this and can provide further information?
As an aside, what do we think about this idea, metaphorical plot holes and all? Clearly it doesn't address some of the protracted and lingering complexities that the BBT does, and yet it explains other core issues that the BBT does not. My interest has been piqued, but as much as I'd love to see big bang cosmology fall to the superfluous wayside - thus silencing men like William Lane Craig momentarily - I don't think I'll get too excited just yet.
The idea that both space and time originated with the BB is still another.
Whether or not the Big Bang Theory turns out to be the correct cosmology or not, it's important to understand it correctly. It's roots lie in a theorem of Roger Penrose on collapsing stars which Hawking reversed, and here I will quote from Hawking's book of 25 years ago. Hawking was the one who realized that Penrose's theorem could be reversed in time:
Penrose's theorem had shown that any collapsing star must end in a singularity; the time-reversed argument showed that any Friedman-like expanding universe must have begun with a singularity.…
The final result was a joint paper by Penrose and myself in 1970, which at last proved that there must have been a big bang singularity provided only that general relativity is correct and the universe contains as much matter as we observe.…
So in the end our work became generally accepted and nowadays nearly everyone assumes that the universe started with a big bang singularity. It is perhaps ironic that, having changed my mind, I am now trying to convince other physicists that there was in fact no singularity at the beginning of the universe—as we shall see later, it can disappear once quantum effects are taken into account.
Stephen Hawking, A Brief History of Time, (1988), p.51
That was Hawking writing 25 years ago.
There are a number of things the big bang explains well—cosmic background radiation and the abundance of lighter elements— and also some very well recognized problems, but in no sense can the origins of the idea be traced back to religious dogma about creation. Neither Hawking nor Penrose hold religious beliefs and a mathematical singularity is not a creation event.
...a mathematical singularity is not a creation event.
That's reasonable, but can a mathematical singularity be a physical singularity?
I bolded the above words to distinguish that question from one I can answer affirmatively: Can a mathematical singularity approximate a physical singularity?
On second thought, a major dictionary I checked defined cosmology as a blend of metaphysics and astronomy. That leads me to say a creation event in a cosmologist's mind might result in a mathematical singularity.
can a mathematical singularity be a physical singularity?
The question seems not to be well formed. What is a physical singularity as distinguished from a mathematical singularity?
The space-time singularity in Penrose's theorem is a point at which the curvature of space-time becomes infinite. The extraordinary physical events and processes occurring in the vicinity of such a point would be completely hidden from an external observer by a surrounding black hole with an event horizon from which no information could escape.
That leads me to say a creation event in a cosmologist's mind might result in a mathematical singularity.
I can't make sense out of this assertion at all.
Dr. Clark, in my one year of graduate school in physics, the other students were all intending to study nuclear physics. I was the loner, intending to study low temperature physics.
I will not let go of my skepticism easily. I do however accept that we don't use the same hardware to determine the location and momentum of electrons and baseballs.
1) Since we won't see a collapsing star in any laboratory, did Penrose have only mathematical support for his theorem?
2) With his theorem in doubt, is not Hawking's reversal also in doubt?
3) Was it a jest among Hawking and his peers about 20 years ago that said Hawking gave the first few nano-nano-etc-seconds of his explanation to the Pope? My skepticism began here.
4) Is it true that the CBR "echo of the BB" is the same in all directions and has no red shift?
5) I might be stating this question wrongly. Given that the singularity became the universe we know now, how large was it when quantum mathematics lost its explanatory usefulness and Newtonian mathematics gained its explanatory usefulness?
Will I someday have to cope with a hypothesis that the conservation of energy functions only in classical physics?
1) Since we won't see a collapsing star in any laboratory, did Penrose have only mathematical support for his theorem?
Penrose's theorem was a deduction from general relativity, which had been tested in several ways. Since he published his results there has been a lot of research directed at detecting black holes through their gravitational effects with the result that the motion of stars orbiting about the center of the Milky Way is fully consistent with the presence of a gigantic black hole there.
2) With his theorem in doubt, is not Hawking's reversal also in doubt?
What makes you think that Penrose's theorem is in doubt? One might ask whether the conditions of its hypothesis are met and hence whether or not it applies, but the theorem itself is not in question to my knowledge. It dates from 1965 and if there were a deductive error, it would likely have been discovered.
3) Was it a jest among Hawking and his peers about 20 years ago that said Hawking gave the first few nano-nano-etc-seconds of his explanation to the Pope? My skepticism began here.
It was a joke recognizing that the laws of general relativity do not apply in the very earliest moments and that a quantum theory of gravity is needed.
4) Is it true that the CBR "echo of the BB" is the same in all directions and has no red shift?
It is very nearly uniform at 2.725K with fluctuations of less than 0.002K. Measurements in different directions show both redshift and blueshift due to the motion of our galaxy.
5) I might be stating this question wrongly. Given that the singularity became the universe we know now, how large was it when quantum mathematics lost its explanatory usefulness and Newtonian mathematics gained its explanatory usefulness?
This question is not well framed. The singularity did not 'become' the universe, it merely marks a point in the space-time continuum where nothing can be said with the physics of the present—neither quantum mechanics nor general relativity is adequate to the task. Thus there is no transition point from quantum mechanics to Newtonian mechanics, which does not really apply at all here.
Will I someday have to cope with a hypothesis that the conservation of energy functions only in classical physics?
As long as you operate in a small segment of the space-time continuum and avoid perpetual motion machines you ought to be OK.
Thank you, Dr. Clark, for your patient explanations. I will continue operating in a small segment of the space-time continuum and avoiding perpetual motion machines.
Mathematical vs. physical?
I worked for a time in NASA's Apollo Program and knew of the mid-course corrections required to get to the moon. Those corrections were necessary because the mathematics treated earth as a sphere with uniform density, not as a slightly flattened sphere with non-uniform density.
It's in that sense that I say a mathematical singularity is not a physical singularity; the mathematics used by cosmologists approximate what exists.
Further, is "space-time continuum" not a metaphor? Metaphor has limits; it is not to be accepted literally.
The diagrams used to illustrate gravity (a "stretchy sheet" with a mass "coasting" around a depression in the sheet) are certainly metaphor.
I find the BBT too compatible with Christian thought and similarly unsupported. It's a rush to closure.
Further, is "space-time continuum" not a metaphor? Metaphor has limits; it is not to be accepted literally.
I find the BBT too compatible with Christian thought and similarly unsupported. It's a rush to closure.
There is no time before the big bang or at precisely at t = 0.
Nor any space at t = 0, as I understand the story.
How very much like Genesis: t = 0 and "In the beginning...."
A college roommate who was studying literature told me (a math/science major) why some fiction becomes famous. I had told him I disliked "reading between the lines", and he replied that's exactly the reason for the fame: people whose lives differ greatly can read the same words and draw different conclusions, and each reader's conclusions relate importantly to his or her own life.
I enjoyed Mark Twain's account of Genesis in his Letters from the Earth.
It's not "move over, Big Bang", yet!
While a beautiful idea, this is very preliminary. For example they do need to explain the cosmic microwave background radiation (which the Big Bang does).
But it's intriguing enough that I'd like to understand the actual paper.
Roger Penrose has another beautiful theory about "Before the Big Bang", also not fully developed. It's called "conformal cyclic cosmology".
Penrose's theorem was a deduction from general relativity
Even though Penrose's theorem doesn't incorporate quantum mechanics, I think it DOES show that in the region of spacetime where GR is relevant without incorporating quantum effects, the curvature tensor does have to diverge towards the realm where quantum effects become important.
So Penrose's theorem is not predicting a singularity when a star collapses into a black hole, but it does predict a region of spacetime in the black hole, where GR fails because the curvature tensor becomes too large.
So Penrose's theorem is not predicting a singularity when a star collapses into a black hole,
Strictly speaking that is exactly what the theorem does say and that is why the theorems are called the Penrose-Hawking Singularity Theorems, but they are speaking of the purely mathematical results from general relativity. Hawking in his joint lectures with Penrose puts the point this way:
The prediction of singularities means that classical general relativity is not a complete theory. Because the singular points have to be cut out of the spacetime manifold one cannot define the field equations there and can not predict what will come out of a singularity. With the singularity in the past the only way to deal with this problem seems to be to appeal to quantum gravity. I shall return to this in my third lecture. But the singularities that are predicted in the future seem to have a property that Penrose has called, Cosmic Censorship. That is they conveniently occur in places like black holes that are hidden from external observers. So any break down of predictability that may occur at these singularities won’t affect what happens in the outside world, at least not according to classical theory.
But it is all still changing and being redone.
Strictly speaking that is exactly what the theorem does say and that is why the theorems are called the Penrose-Hawking Singularity Theorems, but they are speaking of the purely mathematical results from general relativity.
What I was saying is that when you include quantum mechanics (as a complete physics theory has to) the singularity theorem isn't predicting a singularity - but rather that the curvature tensor has to be large enough so one is in the quantum gravity regime, at some spacetime point.
So when you include quantum effects, the singularity is replaced by an area of spacetime where quantum gravity effects are important.
© 2016 Atheist Nexus. All rights reserved. Admin: Richard Haynes. Powered by