Big Bang theory just does not make sense

[saac]

34 minutes ago, billhinge said:

Is there a Newtonian gravitational force on the bottle & water or is it weightless in free fall ? 

 

 

 

 

 

Yes there is, Newtonian at least. The water is a viscous liquid, a Newtonian liquid indeed. As the bottle falls (follows a straight path (geodesic) through the curvature of spacetime) the currents in the water will experience and exert viscous shear forces. Impart a spin on the bottle before you let go and these shear forces will present a delightful vortex in the water. Now how about we replace the water with supercooled liquid Helium! 
Jim 

Edited August 24, 2023 by saac

[saac]

50 minutes ago, Mr Spock said:

I have a BSc 

(bronze swimming certificate)

 

Too my undying shame I don't have one of those.  I can do a couple of lengths and that is it  

Jim 

[Xilman]

7 minutes ago, billhinge said:

Thats the issue with uni physics, they teach the maths but not "Foundations of QM' - I used to believe in Copenhagen but now switched to Many Worlds, you know it makes sense 😉 

I rather like the pilot wave interpretation.

[vlaiv]

13 minutes ago, billhinge said:

Thats the issue with uni physics, they teach the maths but not "Foundations of QM' - I used to believe in Copenhagen but now switched to Many Worlds, you know it makes sense 😉 

I just love many world interpretation and I think that most people don't understand the gist of it, but it simply has a problem that I can't find a way around that tells me it's not (in part or entirely) the explanation.

Here is condensed / simple version of the problem:

Take any event that has two outcomes (polarization of photon or spin of electron) and create setup with different probabilities than 50:50. That is very easy to do - just take electrons with spin that is at certain angle to electric field (not 90 degrees). Each time we perform one experiment world "splits" or shall we say global wavefunction turns into superposition of two new sets of states (history + new measurement up and history + new measurement down) - if you do enough of these - being in one "history chain" will determine probability - but that probability always splits as 50:50 and not by angle - so we can't justify experiment results by being on random branch as any random branch will have history consistent with 50%:50% split and not say 90%:10%

If many worlds interpretation is correct - we would always 50%:50% probability of spin up vs spin down - no matter the angle as there is no "assigned weight" of being one versus the other "copy". Two outcomes create two copies and being either of them is equally likely.

 

[vlaiv]

12 minutes ago, Xilman said:

I rather like the pilot wave interpretation.

Is there any particular interpretation with least or perhaps none objections?

No matter how "crazy" or "not elegant" it may be?

[andrew s]

3 minutes ago, vlaiv said:

Is there any particular interpretation with least or perhaps none objections?

No matter how "crazy" or "not elegant" it may be?

As far as I understand it all interpretations make the same predictions so there is no scientific way to choose.  It is a matter of philosophy not science. 

Regards Andrew 

[billhinge]

2 minutes ago, andrew s said:

As far as I understand it all interpretations make the same predictions so there is no scientific way to choose.  It is a matter of philosophy not science. 

Regards Andrew 

true, take your pick but the nice thing about many worlds is that there is a phone app for it 😉 

[billhinge]

30 minutes ago, saac said:

Yes there is, Newtonian at least. The water is a viscous liquid, a Newtonian liquid indeed. As the bottle falls (follows a straight path (geodesic) through the curvature of spacetime) the currents in the water will experience and exert viscous shear forces. Impart a spin on the bottle before you let go and these shear forces will present a delightful vortex in the water. Now how about we replace the water with supercooled liquid Helium! 

Jim 

Jim 

or you could just use an accelerometer or your mobile phone 😉 

[saac]

18 minutes ago, billhinge said:

or you could just use an accelerometer or your mobile phone 😉 

Mass hanging on a spring balance is easier, use the mobile phone for super slow mo vid.  Makes for a nice theatrical demonstration. 

Jim

[billhinge]

yes provided you drop it from a height and measure the spring extension via video  as it falls, doesn't work if its hanging

[saac]

2 minutes ago, billhinge said:

yes provided you drop it from a height and measure the spring extension via video  as it falls, doesn't work if its hanging

Nope, you hang the mass on the hook, hold it and it registers the weight. Let go, in free fall the pointer indicates 0 N.  You only need to drop it from few m as the slow mo vid of an iphone (120 fps) picks it all up quite nicely.  The iphone is great for these type of demos. 

Jim 

[Ags]

2 hours ago, saac said:

The OP has a lot in common with the BIg Bang - came from nowhere, caused inflation, followed by expansion and nobody knows why!

Come on OP,  send out an echo from the big bang  

Jim 

What I want to know is: what came before the OP's post?

[vlaiv]

1 hour ago, andrew s said:

As far as I understand it all interpretations make the same predictions so there is no scientific way to choose.  It is a matter of philosophy not science. 

Regards Andrew 

Well, that is common wisdom, and according to that - they do make same predictions, but for example - I've outlined where many worlds fails to reproduce experimental results.

I must admit that I haven't read the original paper, so I might be assuming something wrong in the case I outlined - but I'm not the only one to spot the said problem

at least according to this:

[andrew s]

30 minutes ago, vlaiv said:

I've outlined where many worlds fails to reproduce experimental results.

If your correct I don't understand why serious physicists still consider it a valid interpretation.  Personally,  I find it unattractive but that's an ascetic perspective. 

Regards Andrew 

PS I found this

"A popular criticism of the MWI in the past, see Belinfante 1975, which was repeated by Putnam 2005, is based on the naive derivation of the probability of an outcome of a quantum experiment as being proportional to the number of worlds with this outcome. Such a derivation leads to the wrong predictions, but accepting the idea of probability being proportional to the measure of existence of a world resolves this problem. Although this involves adding a postulate, we do not complicate the mathematical part (i) of the theory since we do not change the ontology, namely, the wave function. It is a postulate belonging to part (ii), the connection to our experience, and it is a very natural postulate: differences in the mathematical descriptions of worlds are manifest in our experience, see Saunders 1998."

from here which may be of interest .

Edited August 24, 2023 by andrew s

[billhinge]

1 hour ago, saac said:

Nope, you hang the mass on the hook, hold it and it registers the weight. Let go, in free fall the pointer indicates 0 N.  You only need to drop it from few m as the slow mo vid of an iphone (120 fps) picks it all up quite nicely.  The iphone is great for these type of demos. 

Jim 

isn't that what I just said?  = "Let go, in free fall the pointer indicates 0 N." I didn't specify a specific height

[Paul M]

The late and arguably great, Sir Fred Hoyle, coined the phrase "Big Bang" dismissively^* 

But could "it" have been named any better?

Entries on a postcard... 🤣

 

^* I really liked the Steady State theory as a boy, and at the rate that science was disseminated to the masses by books back then, it was still seriously considered. No scientific evidence on my part, it just upset me less than the idea of a "beginning".

[saac]

12 minutes ago, billhinge said:

isn't that what I just said?  = "Let go, in free fall the pointer indicates 0 N." I didn't specify a specific height

Yea, but I had previously posted . 

"Mass hanging on a spring balance is easier, use the mobile phone for super slow mo vid.  Makes for a nice theatrical demonstration. "

Maybe cross posted  

Jim

[saac]

23 minutes ago, Paul M said:

The late and arguably great, Sir Fred Hoyle, coined the phrase "Big Bang" dismissively^* 

But could "it" have been named any better?

Entries on a postcard... 🤣

 

^* I really liked the Steady State theory as a boy, and at the rate that science was disseminated to the masses by books back then, it was still seriously considered. No scientific evidence on my part, it just upset me less than the idea of a "beginning".

Well the author of the theory called it the Primordial Atom.  Yes Hoyle's term was pejorative, perhaps tinged with a bit of professional jealousy. Lemaitre prevailed  

Unfortunately the term Big Bang stuck even though it was/is wholly misleading and seeds so many misconceptions. 

Jim 

Edited August 24, 2023 by saac

[vlaiv]

1 hour ago, andrew s said:

but accepting the idea of probability being proportional to the measure of existence of a world resolves this problem.

Ok, now that is an "explanation"

Now we have a measure of existence of a world

Ok, let me put it this way. I'm going to exaggerate a lot here - but just to get my idea across.

We prepare electron with a spin in a such way that probability of it being a spin up 0.999999999999... (and now imagine one hundred nines behind the first zero - or in another words - "ridiculously" high probability).

Now we perform an experiment with such electron and we get world wave function to be in superposition of <electron up and we measured it up> and <electron down and we measured it down>

Now one copy of us is already raising their brow - now what a coincidence - we just achieved experiment result with spectacularly small probability - but that is ok because we "don't exist" that much

Now we repeat the experiment - both copies.

We now have 4 copies in superposition. One copy is on the floor laughing since they measured such an unbelievable odds twice in row - and they just feel fading out of existence

2 of remaining 4 copies - have now their eyebrow raised, again not believing their luck and feeling like they are starting to "vanish out of existence" or something

Only remaining copy is happy as they are - having strong measure of existence.

See where I'm going with this - and how ridiculous that explanation is - measure of existence of a world. It is component of super position of wave function and as such, if we accept global wave function to be item of reality (and many worlds strongly does so) - one part of it can't be more existing than others - they all exist.

[andrew s]

@vlaiv I am certainly not trying to defend it. If I had to choose I would reject interpretation and side with "shut up and calculate ".

After all that's what models are for, however unsatisfied that leaves our need for explanation. 

Regards Andrew 

[Xilman]

15 hours ago, saac said:

Yes they do but you don't build and operate a particle collider without Newtonian mechanics  - stress, strain, acceleration, momentum, compression, expansion, cooling, fabrication of steel , concrete, generation of electricity etc.  That is the point I was making - we live and function in a Newtonian realm and we have discovered the quantum through that. 

Jim 

 

You don't operate one without special relativity. Things get heavier as they move faster, so they are harder to bend round corners with magnets, the strength of which have to be altered accordingly as the particles are accelerated. The particles travel at essentially the speed of light when they are at high enough energy so to know where they are, the timing of the accelerating pulses of energy requires SR once again.

These are only two examples. Designing and operating the detectors provide more.

[vlaiv]

3 hours ago, andrew s said:

@vlaiv I am certainly not trying to defend it. If I had to choose I would reject interpretation and side with "shut up and calculate ".

After all that's what models are for, however unsatisfied that leaves our need for explanation. 

Regards Andrew 

I just think that many worlds is interesting because:

a) I really like it, it is elegant

b) it fails to explain frequency of outcomes

We can learn something from all of this, I believe. One obvious thing would be to assert that one of axioms of this interpretation is simply wrong. Other would be to reconsider our understanding of probability and what it means.

 

[AstroMuni]

2 minutes ago, ollypenrice said:

Also, the idea that there is a past, a moving present and a future is what kind of idea?  It is, dear friends, a theory and it is a theory which has taken some heavy knocks from theoretical physicists... I'm convinced we need a more generalized theory of time.

Thats deep. And here I was thinking that I knew that we had a past, a present & a possible future (in this world) 🙂

[vlaiv]

In case anyone cares, I have a new favorite interpretation of QM (and I wonder how I did not come across that earlier):

https://en.wikipedia.org/wiki/Transactional_interpretation

 

[saac]

1 hour ago, Xilman said:

You don't operate one without special relativity. Things get heavier as they move faster, so they are harder to bend round corners with magnets, the strength of which have to be altered accordingly as the particles are accelerated. The particles travel at essentially the speed of light when they are at high enough energy so to know where they are, the timing of the accelerating pulses of energy requires SR once again.

These are only two examples. Designing and operating the detectors provide more.

True but I was being more general in intention.  For example you build and operate in accordance with Newtonian mechanics because that is the regime in which we function and operate. The electric fields and cryogenic cooling used by our particle accelerator rely on machines constructed and operated under governance of Newtonian mechanics.  Yes, in the final analysis we can reduce every interaction to  a quantum origin but that is not the point I was making. Decoherence removes us from that direct interaction and awareness.  So yes, once we use  quantum theory or SR to calculate the desired speed of our particle and hence energy level of our accelerator - we turn a handle, flick a switch to generate more electricity, greater cooling, higher magnetic flux etc - all produced via Newtonian processes.  But I would argue that the greater part of our operation of the machine is Newtonian by necessity.  I'm not dismissing QM/SR or GR, far from it - I'm just not relegating Newtonian physics.  

Jim 

 

 

 

 

 

 

Edited August 25, 2023 by saac