How Physics works.

How does science work? And what's all this about quantum mechanics?

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uwot
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How Physics works.

Post by uwot »

Yeah, I've been tinkering. The final chapter is now called How Physics works. If you've ever wondered why people complain that physics makes no sense, this might help explain why it does, even if it isn't perfect.
http://willijbouwman.blogspot.co.uk

(Oops! Had to correct the address.)
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Greta
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Re: How Physics works.

Post by Greta »

I like the poetry of it, but do you mean that each event is retained as part of the fabric of a 4D spacetime manifold?
Dubious
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Re: How Physics works.

Post by Dubious »

I wasn't sure whether I should say anything being certain I misunderstood your meaning. But I still can't make sense of it which kind of bothers me.

In your final graphic you mention, in essence, that we, and obviously all life is a side-effect of everything the Big Bang created in its wake which all makes perfect sense. But you then continue with...
...every atom of your being, every arrangement of atoms that gave rise to every thought you ever had, has been generating Big Bang stuff that will be part of the Universe forever.
...don't you mean "has been generated by Big Bang stuff"? Also, isn't it a little bit of a stretch to conclude with, "...will be part of the universe forever", especially, as I understand it, all information itself is subject to entropy? Though not proven but only speculated upon at this time, the universe may itself only exist for an infinitesimal moment relative to the duration of a multiverse which may contain it.

I don't know anywhere near what you know on the subject so it's not a criticism but merely an inquiry.

Impressive work, BTW!
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Greta
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Re: How Physics works.

Post by Greta »

The banging is not over. It is said that the Big Bang continues to "bang", because it's an inflation of energy rather than explosion.
uwot
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Re: How Physics works.

Post by uwot »

Greta wrote: Thu Jul 27, 2017 2:25 pm I like the poetry of it, but do you mean that each event is retained as part of the fabric of a 4D spacetime manifold?
Depends what you mean by 4D spacetime manifold. In the context of general relativity, some physicists take it literally; meaning that spacetime is a 'fabric', made of width, depth, height and time, in which matter does its thing. It is this approach that admits the possibility of other dimensions, as in string-theory. Others take an instrumentalist approach and treat dimensions as conceptual/mathematical tools, so that any event can be located in space and time by x,y,z and t, relative to some given point. Personally, I don't think dimensions 'exist' in the former sense.
uwot
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Re: How Physics works.

Post by uwot »

Dubious wrote: Thu Jul 27, 2017 8:11 pmI wasn't sure whether I should say anything being certain I misunderstood your meaning. But I still can't make sense of it which kind of bothers me.
I'm very glad you did say. The whole exercise is an attempt to give a sense of what the current state of physics looks like.
Dubious wrote: Thu Jul 27, 2017 8:11 pmIn your final graphic you mention, in essence, that we, and obviously all life is a side-effect of everything the Big Bang created in its wake which all makes perfect sense. But you then continue with...
...every atom of your being, every arrangement of atoms that gave rise to every thought you ever had, has been generating Big Bang stuff that will be part of the Universe forever.
...don't you mean "has been generated by Big Bang stuff"?
Well, as Greta says, "The banging is not over". No one knows what happened at the Big Bang. We don't know what the conditions in which the Big Bang took place. One option is the The Friedmann–Lemaître–Robertson–Walker metric, which has been tweaked to account for the accelerating expansion, in the form of the lambda, cold dark matter model. Despite the fancy names, they are just the simplest models that account for what we can actually see, essentially: there's some stuff and it's getting bigger. All I have done is to point out that if the universe is made of this expanding stuff, so is everything in it.
Greta continues:
Greta wrote: Thu Jul 27, 2017 11:30 pmIt is said that the Big Bang continues to "bang", because it's an inflation of energy rather than explosion.
Which is pretty much what I have tried to illustrate.
Dubious wrote: Thu Jul 27, 2017 8:11 pmAlso, isn't it a little bit of a stretch to conclude with, "...will be part of the universe forever", especially, as I understand it, all information itself is subject to entropy?
Fair point. I usually visualise entropy as a very tightly wound spring, that has been released. For a while, it goes completely bonkers; the waves and ripples, being analogous to particles and forces, but eventually, the spring goes 'flat'. That is equivalent to heat death, and you are quite right, 'forever', is a bit misleading, but we're talking trillions of years, which is near enough.
Dubious wrote: Thu Jul 27, 2017 8:11 pmThough not proven but only speculated upon at this time, the universe may itself only exist for an infinitesimal moment relative to the duration of a multiverse which may contain it.
Could be.
Dubious wrote: Thu Jul 27, 2017 8:11 pmI don't know anywhere near what you know on the subject so it's not a criticism but merely an inquiry.
Please feel free to criticise. It really helps to know what I haven't explained clearly.
Dubious wrote: Thu Jul 27, 2017 8:11 pmImpressive work, BTW!
Thank you.
Belinda
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Re: How Physics works.

Post by Belinda »

Are you the author, Uwot? It's marvellous!
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Greta
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Re: How Physics works.

Post by Greta »

I'll reiterate Belinda's sentiment. That is a large and ambitious project. There's tons on info out there but which to emphasise? Just teasing that out is enough of a task let alone getting the wording, graphics and design worked out!
uwot wrote: Fri Jul 28, 2017 10:13 am
Greta wrote: Thu Jul 27, 2017 2:25 pm I like the poetry of it, but do you mean that each event is retained as part of the fabric of a 4D spacetime manifold?
Depends what you mean by 4D spacetime manifold. In the context of general relativity, some physicists take it literally; meaning that spacetime is a 'fabric', made of width, depth, height and time, in which matter does its thing. It is this approach that admits the possibility of other dimensions, as in string-theory. Others take an instrumentalist approach and treat dimensions as conceptual/mathematical tools, so that any event can be located in space and time by x,y,z and t, relative to some given point. Personally, I don't think dimensions 'exist' in the former sense.
So if we say that the spacetime block universe is a model rather than physical reality, then if everything is retained, then I take it you are referring to events as historical facts whose knock-on effects will probably always in some imperceptible way will be reflected by current reality? Otherwise, according to the standard model, the order of information in events is utterly lost even if the information itself remains, eg. 1. death 2. if you fall into a black hole then the order that makes you "you" will be completely lost, but the information will be smooshed around the event horizon, adding infinitesimally to the horizon's total information content.

Then again, wouldn't entanglement's spooky action at a distance and so-called singularities suggest other dimensions? (and not necessarily Minkowski space as such).
Impenitent
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Re: How Physics works.

Post by Impenitent »

just an aside...

before the "big bang" there was nothing yes?

all the matter in the universe collected at one point and "bang" then it spread to the corners of the universe...

if it "banged," who heard it?

-Imp
uwot
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Re: How Physics works.

Post by uwot »

Belinda wrote: Fri Jul 28, 2017 6:30 pm Are you the author, Uwot? It's marvellous!
Thank you, Belinda. Yes it's all my own work.
uwot
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Re: How Physics works.

Post by uwot »

Greta wrote: Fri Jul 28, 2017 10:50 pmI'll reiterate Belinda's sentiment. That is a large and ambitious project. There's tons on info out there but which to emphasise? Just teasing that out is enough of a task let alone getting the wording, graphics and design worked out!
Thank you too, Greta. Yes; it's been a bit of a mission. Still is.
Greta wrote:So if we say that the spacetime block universe is a model rather than physical reality, then if everything is retained, then I take it you are referring to events as historical facts whose knock-on effects will probably always in some imperceptible way will be reflected by current reality?
I don't know if the block universe is the case. I can't think how you could test it, so it comes under "Nothing is too wonderful to be true, if it be consistent with the laws of nature”. As for our current reality, the cosmic microwave background radiation is part of it, and while there's not much going on in my head on the scale of the Big Bang; assuming a physicalist interpretation of consciousness, it's still creating waves.
Greta wrote:Otherwise, according to the standard model, the order of information in events is utterly lost even if the information itself remains, eg. 1. death 2. if you fall into a black hole then the order that makes you "you" will be completely lost, but the information will be smooshed around the event horizon, adding infinitesimally to the horizon's total information content.
It's not really something I would defend with any vigour; the energy is absolutely piffling, but you never know.
Greta wrote:Then again, wouldn't entanglement's spooky action at a distance and so-called singularities suggest other dimensions? (and not necessarily Minkowski space as such).
Well, entanglement is real enough, whether it's spooky action at a distance, I don't know, but if Big Bang stuff is a fair reflection of reality, then there is the means for entangled pairs to be connected mechanically; 'locally' as it is often referred to.
I take it you mean gravitational singularities, in which the density of matter, and hence gravity is infinite. Well, they pop up in mathematics; whether they exist in the 'real world' is a different matter. I'm a bit of an instrumentalist, when it comes to dimensions. Cartesian co-ordinates are useful for discovering where you left your keys, but I don't think it follows that they refer to anything material.
uwot
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Re: How Physics works.

Post by uwot »

Impenitent wrote: Fri Jul 28, 2017 11:15 pm just an aside...

before the "big bang" there was nothing yes?
No idea. We simply don't know what conditions the Big Bang took place in. Candidates include a proper vacuum, a quantum vacuum, some corner of a multiverse, god's hankie; who knows?
Impenitent wrote: Fri Jul 28, 2017 11:15 pmall the matter in the universe collected at one point and "bang" then it spread to the corners of the universe...

if it "banged," who heard it?

-Imp
Well as I say: "...the Big Bang wasn’t caused by a quick burning explosive.
What appears to have happened, is that Big Bang stuff didn’t really explode so much as it grew."
And as Greta alludes to above: "As far as we can tell, there is no good reason to think it has ever stopped. Whatever Big Bang stuff is, it just keeps on growing."
Belinda
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Re: How Physics works.

Post by Belinda »

Uwot wrote:
Well as I say: "...the Big Bang wasn’t caused by a quick burning explosive.
What appears to have happened, is that Big Bang stuff didn’t really explode so much as it grew."
And as Greta alludes to above: "As far as we can tell, there is no good reason to think it has ever stopped. Whatever Big Bang stuff is, it just keeps on growing."
It's easier to picture (and 'picturing' is all that I not-a-physicist am capable of)the process of creation continuing than ending. What sort of friction or something could end creation? I am thinking in particular of uwot's drawing of exponential proliferation. I cannot give a reference to the drawing I have in mind but it is something like light blue circles . Does 'How Physics Works?' have an index?
uwot
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Re: How Physics works.

Post by uwot »

Belinda wrote: Sat Jul 29, 2017 9:41 am It's easier to picture (and 'picturing' is all that I not-a-physicist am capable of)...
You're in good company. Despite the (thoroughly deserved) godlike reverence Einstein commands, he wasn't that great a mathematician. He once said, off the top of my head, 'Coming up with relativity was easy. Proving it was almost impossible.'
Belinda wrote: Sat Jul 29, 2017 9:41 am...the process of creation continuing than ending. What sort of friction or something could end creation?
Well, it used to be thought that gravity would slow down, and eventually undo the expansion of the universe, resulting in a Big Crunch. That was before it was discovered that the expansion is actually accelerating; so that's not going to do it. The end of creation is probably going to happen because of heat death. This just means that the universe is so stretched out that everything is like very long waves; but for anything to be 'matter', you need whirlpools and eddies in the fabric of the universe. It's a bit like filling your sink and giving it a stir. At first, the energy you put in will create the sort of turbulence you need to make 'atoms', but eventually, everything calms down and all that's left are gentle ripples. The last estimate I saw for this happening to the universe was 17 trillion years.
Belinda wrote: Sat Jul 29, 2017 9:41 amI am thinking in particular of uwot's drawing of exponential proliferation. I cannot give a reference to the drawing I have in mind but it is something like light blue circles . Does 'How Physics Works?' have an index?
Not yet. I'm working on it.
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HexHammer
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Re: How Physics works.

Post by HexHammer »

uwot wrote: Thu Jul 27, 2017 11:58 am Yeah, I've been tinkering. The final chapter is now called How Physics works. If you've ever wondered why people complain that physics makes no sense, this might help explain why it does, even if it isn't perfect.
http://willijbouwman.blogspot.co.uk
Please stop promoting your utterly bad physics site, it's more misleading that tutoring!
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