Very interesting how the new physics is explaining the cause of the Big Bang event now. After reading, it would be good to see a timeline here. Before the BB event, BB event, and moments just after the BB event. Is the dark energy that floods the early universe with exotic particles that evolve into atoms (exactly what atoms on the Periodic Table for example), when does this creation event take place? After inflation is indicated but we have the Planck time, Planck length, and evolution of the universe that followed and one second after the BB event, the matter vs. anti-matter destruction of everything too. It seems the new physics goes back before the Planck time and perhaps smaller than the Planck length now, at least it may. James Peebles had something to say about the new math explaining the BB event. ‘Top cosmologist's lonely battle against 'Big Bang' theory’ "One of these theories is known as the "inflation model," which holds that the early universe expanded exponentially fast for a tiny, tiny fraction of a second before the expansion phase. "It's a beautiful theory," said Peebles. Many people think it's so beautiful that it's surely right. But the evidence of it is very sparse."
It is basically very supernumerary since inflation makes the same predictions, and ad hoc to better suit the observations.
When you say "Big Bang event" you define it as the start of the Hot Big Bang era ["The Big Bang is Probably Not What You Think It Is"Very interesting how the new physics is explaining the cause of the Big Bang event now. After reading, it would be good to see a timeline here. Before the BB event, BB event, and moments just after the BB event. Is the dark energy that floods the early universe with exotic particles that evolve into atoms (exactly what atoms on the Periodic Table for example), when does this creation event take place? After inflation is indicated but we have the Planck time, Planck length, and evolution of the universe that followed and one second after the BB event, the matter vs. anti-matter destruction of everything too. It seems the new physics goes back before the Planck time and perhaps smaller than the Planck length now, at least it may. James Peebles had something to say about the new math explaining the BB event. ‘Top cosmologist's lonely battle against 'Big Bang' theory’ "One of these theories is known as the "inflation model," which holds that the early universe expanded exponentially fast for a tiny, tiny fraction of a second before the expansion phase. "It's a beautiful theory," said Peebles. Many people think it's so beautiful that it's surely right. But the evidence of it is very sparse."
When it comes to *sparse* evidence, I compare the new cosmology to the debate between geocentric teaching and heliocentric solar system and what type of science won the day and changed the paradigm. For example, I find the measurements for the solar parallax (that determined the astronomical unit) using transits of Venus and Mercury with telescopes more reliable and verifiable than the new cosmology doctrine that explains what was there before the BB event and how the BB event took place.
Expansion rate is measured in many ways. Planck 2018 cosmology parameter paper @ Planck Legacy Archive is an older synthesis:Perhaps I was not clear enough here concerning cosmology and comparing it to the science of the heliocentric solar system. The solar parallax can still be measured and determined today using telescopes, An Experiment in Solar Parallaxes, this is part of the heliocentric solar system science like predictions of Galilean moon eclipses and transits. Is there experimental measurement that shows the rate of 3D space expansion during inflation (>> c velocity) - is verified like modern measurements of the solar parallax?
I'm not sure what expansion rate you are discussing now, since you mention inflation. This is by the way a basic reason, I think, why astrophysicists separate between the inflation era with high expansion rate and the big bang era with low expansion rate, we are talking different expansion rates as well as measurements.Thanks for the references. I do not see where 3D space expanded >> c has been verified by experiments or even that 3D space is expanding here on Earth or in the solar system like direct measurements for the solar parallax in the history of astronomy. The history of conflict in measuring H0 is well documented, since the days of Edwin Hubble when H0 reported about 500 showing a universe < 2E+9 years old. When it comes to inflation, the ability to measure the velocity of 3D space expansion *during inflation* is not the same as the ability to verify the solar parallax value, this is my main point.
Others say inflation is not proven at this time. https://astronomy.com/magazine/2018/07/inflation-leaves-its-mark, “With inflation, the number of observational quantities we have is limited,” says Marc Kamionkowski, a professor and theoretical physicist at Johns Hopkins University. “Therefore, it limits the level of detail at which the model or theory can be specified...In the past four decades, inflation has become a central pillar around which cosmology is organized. But while it tidies up outstanding problems with the Big Bang theory, it remains unverified. And the lack of evidence leaves some scientists with reservations. “It’s had incredible success at describing what we see . . . and people talk about it as the only option, but many theorists think that we should be considering other options for what happened in the early universe,” Dunkley says. “I think it’s unlikely that it happened exactly the way we’ve been thinking about it. I don’t think we’ve got the whole story yet.” For now, inflation remains cosmologists’ best theory to explain the current structure and infancy of our universe. Perhaps it will be another half-century before scientists have a clearer understanding of what happened in the universe’s first breaths."
Here is the key concerning inflation in cosmology "...it remains unverified". The solar parallax is verified and verifiable today, just like the measurement was in the 1700s using Venus or Mercury transits across the Sun or even later observations.
So I read the paper as I should in the first place, and it is not supernumerary in all senses. It is a suggestion of a possible energy exchange between vacuum and matter sectors in the very early universe, right after baryons have frozen out, so it does not add new fields as much as asks for constraining possible theory effects. And while it is the Hubble rate tension that motivates them, their fitted model predicts the lowest scales of the matter power spectrum (how much baryon matter at different scales, I think) better than LCDM. The lowest scales of the cosmic background spectra has some deviation, i.e. the largest background spatial spots of temperature variation differs from predictions, and if the largest matter "spots" becomes better predicted maybe that helps.It is basically very supernumerary since inflation makes the same predictions, and ad hoc to better suit the observations.
The only reason to raise it now is since there is a tension in observations of expansion rate, which roughly divide between methods looking at the local - or youngest - data and global - heavily weighted with oldest - data. And one early suggested, suitable and simple ad hoc for that is that dark energy had a temporary early extra component. But that, and/or the application here, is still very weak in nature.
Going down the wrong path is just that."Did dark energy cause the Big Bang?" No. If you want to see how the last 50 years or so have been completely wasted when it comes to astrophysics and cosmology start reading less click-bait garbage like this and start reading Peter Woit and his page "Not Even Wrong" along with Sabine Hossenfelder and her page "Backreaction."
Dark energy, dark matter, what the universal constants even are, Hubble constant, string theory, etc. A lot of it is garbage math and garbage theories based on flawed observation methods. Peter Woit and Sabine Hossenfelder do a lot to shed light on how bad the past 50 years has been. Whole generations of scientists are working on what will end up going absolutely nowhere because scientific leadership has chosen protect theories that need to be revisited. The large hadron collider should have made this clear with multiverse, supersymmetry and string theory largely shown to be garbage by the results there - but 90% of the field decided to take result and continue the insanity.
Its time to look at the sacred cows and stop doing this pop-science big-bang-theory-tv-show brian greene/neil tyson/bill nye garbage science and click-bait.
Thank you!Torbjorn, some interesting comments you present. Here is my bottom line upfront The redshift of light from galaxies, I do like the interpretion as evidence for an expanding universe based upon the *cosmological redshift* interpretation but do not consider the interpretation of the redshifts as secure in testing like the solar parallax measurements since the 1700s for the astronomical unit.
Inflation is very different than the cosmological redshift interpretation of light, it depends upon quantum gravity, inflatons, and inflation field(s) as well as 3D space expanding >> c.
The first claim breaks causality, an event cannot produce itself. That we live is evidence that a shortlived - very shortlived - fluctuation is not what we are.More likely that a big bang causes the big bang ... IMO quantum fluctuation is the universe and big bang just an event inside it.
That shows nothing of the sort since they are fringe, more like the usual 1 % fringe of all areas than the 10 % you claim. If anything it shows that science is not waste - it generates criticism, so can test itself - and that they are apriori less likely to be correct."Did dark energy cause the Big Bang?" No. If you want to see how the last 50 years or so have been completely wasted when it comes to astrophysics and cosmology start reading less click-bait garbage like this and start reading Peter Woit and his page "Not Even Wrong" along with Sabine Hossenfelder and her page "Backreaction."
Not our big bang, big bang from another universe causes our big bang. FTL expansion of an external big bang only real way to release a universe size black hole (ours).The first claim breaks causality, an event cannot produce itself. That we live is evidence that a shortlived - very shortlived - fluctuation is not what we are.
It is one possibility among many.No way round the idea that the universe is fluctuation
Fun! FWIW, I agree on the database, but no such will be complete/completely satisfying for every user, nor will a vocabulary be rigid and consistent since both language and science evolve. At the same time we are discussing some recent results that has barely settled. I am sure there are popular science resources that are easier to digest, but - with the caveats that peeer review is fallible and scholars can have narrow interests - Scholarpedia comes to mind [ http://www.scholarpedia.org/article/Main_Page ]. If you haven't heard of it, maybe that is a tip. I haven't had time to peruse it much, just when something fits. It has a very nice article on the long term stability of the solar system, by the way.FYI. As I dig deeper into quantum cosmology, I find many interesting terms like QFT, inflatons, inflaton field, magnetic monopole, etc. Here is an example.
"Inflation is most often described using quantum field theory (QFT) on a fixed, curved spacetime background. Such a description is valid only if the spatial volume of the region considered is so large that its size and shape moduli behave classically. However, if we trace an inflating universe back to early times, the volume of any comoving region of interest—for example, the present Hubble volume—becomes exponentially small. Hence, quantum fluctuations in the trajectory of the background cannot be neglected at early times. In this paper, we develop a path integral description of a flat, inflating patch (approximated as de Sitter spacetime), treating both the background scale factor and the gravitational wave perturbations quantum mechanically. We find this description fails at small values of the initial scale factor, because two background saddle point solutions contribute to the path integral. This leads to a breakdown of QFT in curved spacetime, causing the fluctuations to be unstable and out of control...Our discussion emphasizes that, even if the inflationary scale is far below the Planck mass, new physics is required to explain the initial quantum state of the universe."", Quantum incompleteness of inflation
A complete database showing all these new physics with interesting fields, particles, and quantum cosmology components needs to be posted online, for all to read and see I feel, not all the math, just the vocabulary terms and concepts
Just a very simple way to go from nothing to everything.It is one possibility among many.
There are reasons why theoretical physicists wants initial conditions for processes, and especially here, but they are arguable, and especially here.
In general if we would look back we would ask for an added process that sets that condition - that is inherently less likely. And here an infinitely large turtle is in principle infinitely much likelier than an infinite series of turtles all the way down.
The observed slow roll inflation may stand up, and it makes many of the special hypotheses that says you will go to Planck scale - the scale of general relativity fluctuations* - wrong or problematic. It can roll indefinitely - it is in the name - and expands inflating space faster than exciting inflation will remove space. For example, the conditions that say general relativity will break do not apply.
On some points you raised:
- The universe is not a black hole [ https://www.discovermagazine.com/the-sciences/the-universe-is-not-a-black-hole ]. It is expanding, not collapsing. And it has no boundary such as the Schwarzschild radius. The basic thing these two systems have in common is that they share the condition that the distant universe is flat. See the link why that - when quantified - leads to confusion by many.
- A hot big bang cannot produce another hot big bang either. Instead some similar physics is possible, a big bang universe with a certain vacuum state - dark energy - can theoretically tunnel to a lower energy state [Hawking et al]. However, this is theoretic and the whole point with a big bang is that it goes ta the vacuum state so we are in a pretty low energy state already. In fact 10^-120 times lower than a naive estimate would say.
* Fluctuations that are not perturbative - basically, linear - that is. Large, uneven masses will generate gravitational waves by perturbation as they move, at much lower energies.
I think that hurt my brain LOLFun! FWIW, I agree on the database, but no such will be complete/completely satisfying for every user, nor will a vocabulary be rigid and consistent since both language and science evolve. At the same time we are discussing some recent results that has barely settled. I am sure there are popular science resources that are easier to digest, but - with the caveats that peeer review is fallible and scholars can have narrow interests - Scholarpedia comes to mind [ http://www.scholarpedia.org/article/Main_Page ]. If you haven't heard of it, maybe that is a tip. I haven't had time to peruse it much, just when something fits. It has a very nice article on the long term stability of the solar system, by the way.
"quantum cosmology", "QFT, inflatons, inflaton field, magnetic monopole".
Speaking of Scholarpedia, if you want a complete quantum cosmology you may want to look at how linearized gravity can be quantized [ http://www.scholarpedia.org/article/Quantum_gravity_as_a_low_energy_effective_field_theory ]. It may or may not break down in nature - the whole idea of "effective" quantum field theory is that it will under some conditions - but as I just said in another comment: An infinitely large turtle is in principle infinitely much likelier than an infinite series of turtles all the way down* (or up, in energy scale). Else people tend to think of either semiclassical cosmology - keeping general relativity classical - or something like string theory.
Not being a theoretical physicist it is hard to filter out the stuff one shouldn't worry about. My filter need not apply to you, but in case you wonder how I look at it:
- Magnetic monopoles have never been observed, and they arise in theories that are arguable less likely today. "Modern interest in the concept stems from particle theories, notably the grand unified and superstring theories, which predict their existence." [ https://en.wikipedia.org/wiki/Magnetic_monopole ] GUT implies in general that protons decays, but we do not see that. And string/superstring theory imply natural WIMPs that LHC and ACME did not see.
- Quantum field theory, obviously as it is "simply" the relativistic version of quantum mechanics, and the inflation field has both been observed on the other hand. For example. Planck especially sees inflation and the imprint of the field fluctuations that eventually resulted in cosmic background areal spots, spot orientation polarization and cosmic filaments. (The latter which other sky surveys also see.)
- The inflatons were diluted during inflation, and would have decayed right after the field did anyway, and I don't think we can reach those energies in accelerators in near term (or ever). If inflation is eternal, the inflationary field was effectively emptied out of inflatons - its temperature was effectively cooled to 0 K. (Which will take infinite dilution/adiabatic cooling time, but here we may have infinities and eat them too.) And since we don't see inflatons in any case I think the original idea became that these particles were unstable and decayed. The field potential Planck sees looks Higgs like, so presumably any particles during inflation would not have their vacuum state mass like Higgs eventually got - which is why any of them would decay, AFAIU, precisely compliant with the original idea. Maybe it isn't important, there are lots of field excitations that physicists likes to kick around (say, "virtual particles" that have imaginary mass if you treat them like particles and try to derive mass - they are non-resonant excitations, not resonant excitations like bona fide particles).
"Quantum incompleteness of inflation".
Turok is the last author, so his interest would be to do away with inflation so he can make his bouncing universes more appetizing. This is not my specialty, but from the abstract I would deem that they approximate a flat, inflating patch as a de Sitter spacetime and then say something about de Sitter spacetime. Not really convincing.
Here is the fun in this (but maybe it is me just being sophistic): The topology of a de Sitter space time has a bottleneck as in a conic section if you glue two copies together in the narrow end at the Planck scale, to get a smooth topology to study. So of course you run into problems if you go to such scale sizes in a universe that started out that way (at the bottleneck). But we know that the topology of spacetime can be flat if we want to consider a non-bouncing universe. So we can approximate Turok's de Sitter universe with a flat space and that leads to a breakdown of bouncing universe physics in as much as it relies on de Sitter space and that bottleneck and its problems. In such a case, to quote the paper, "new physics is required", preferably something that works in flat space. LCDM cosmology comes to mind.
That said, it is nice to discuss new stuff. But since I did not read Turok et al I was a bit lazy on my part. I hope you have non-lazy fun in your further digging!
* If you take the analogy to biology, it breaks. It works out as equally easy on cell level, exponential growth of population is exponential growth in mass, so it doesn't matter if you build a single turtle or a chain of equal massed ones. Analogies are still analogies, I guess.
Well, as long as we agree it is not the only alternative.Just a very simple way to go from nothing to everything.
That also means that before the first big bang anywhere it was all fluctuation so expansion of a big bang is an illusion of everything or an event inside it.
Just expansion of the big bang event in a foggy bubble of fluctuation.
I have a feeling that is the way it since creating nothing is very difficult with fluctuation trying to fill nothing ASAP.
Could be just a property of nothing spawns fluctuation, a potential energy of nothing.
I think the common thought of gravity is wrong.
Gravity IMO is just compression or has no interaction with fluctuation or travels in the nothing between fluctuation.
Instant travel or just compression passing through nothing makes gravity a simple beast.
SPAD with gravity entanglement very simple solution.
SPAD as particle entanglement very difficult.
Black hole infinite mass/gravity+ singularities
Or simple compression of an area self regulated size by lack of activity (no fluctuation/time).
I love simple solutions
Oh i agree no guarantee my idea will be right.Well, as long as we agree it is not the only alternative.
But as I implied earlier, the idea of "nothing" - which originates in simplistic thinking of disappeared objects perhaps,the memory of the discovery of peekaboo in children, and in any case is a religious meme - makes little sense. Since all we know when we look back is "something", it is an extraordinary claim that would need extraordinary evidence. Not exactly "simple", as you suggest, but very, very hard. Get back to me when you have the extraordinary evidence that suggests it.
This applies also to your opinion that "common thought of gravity is wrong". Here you would need to show the peer reviewed quantification that show you have a superior theory that describes all that general relativity describes, but better. Mind that the general relativistic LCDM cosmology is the best decscription we have seen so far. And also mind that competing theories are the ones that have failed miserably, nearly all of them, due to our observations of the neutron star binary merger:
"New observations of extreme astrophysical systems have “brutally and pitilessly murdered” attempts to replace Einstein’s general theory of relativity. " [ https://www.quantamagazine.org/troubled-times-for-alternatives-to-einsteins-theory-of-gravity-20180430/ . ]