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Physics, Astronomy & Cosmology / Is there a connection between slow motion filming and time dilation?

« on: 29/03/2024 13:42:32 »

This seems like such an obvious question that I am surprised it is the first time it has occurred to me .

When we speed up the recording of a film and play it back at a slower speed we see everything slowed down.

Again , if an object is in relative motion to our frame of reference we "see" things slowed down  in it (as in the twin astronauts scenario and others)

If we speed up the recording of the film to the maximum the speed of the replay goes to zero.(with no loss of detail)

Is this just an analogy for time dilation or is this more or less how time dilation actually works?

(I realize ,I think that the doppler effect plays no part in slow motion filming but I am not concerned with it for this question.)

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Physics, Astronomy & Cosmology / What is the relationship between an object and its field?

« on: 13/03/2024 00:09:25 »

As an example an electron and its electric field?

In QFT the former is described as an excitation of the latter,I believe.

Are there other ways of looking at it?

Can we imagine the field as an extension of the object(the two being aspects of the greater whole)?

Or is it just  easier to imagine it the other way round with the object being  some kind of  an "appendage" of the field ?(that would be more  along the lines of the QFT model ,I think)

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Physics, Astronomy & Cosmology / Is time dilation caused just by relative motion(not acceleration)?

« on: 06/02/2024 23:11:15 »

I understand that the idea that time dilation is caused by acceleration  is a mistaken one(one that I laboured under for some time)and that it is actually relative  motion that is the cause.

I have also seen it stated that it is possible to produce  two scenarios with the same accelerations but with different resulting time dilations(because of  different relative motions ,presumably)

I did not see(I mean they were only mentioned in passing and not described specifically) any such actual examples .

Can anyone here produce such an example,just for my curiosity?

Ps I have changed the title of the thread so it now reads as a question ,as we are supposed to do.

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Physics, Astronomy & Cosmology / Are quantum systems dynamic?

« on: 28/12/2023 17:53:46 »

A classical system is clearly dynamic.

Can the same be said about a quantum system?

Can quantum system be said to evolve (I think so)?

Do they ,then evolve in discrete ways and not in a continuous fashion except when viewed as part of a classic system?



Hope the question makes some kind of sense as I don't have a very deep acquaintance with QM.

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Physics, Astronomy & Cosmology / How do or can we measure entropy in a system?

« on: 18/06/2023 13:57:28 »

If this is possible can we measure the entropy of an individual  mind or a system of  minds?

And what about the observable universe ,would there be any rough number associated with it?

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Physics, Astronomy & Cosmology / Are there any philosophical or other implications to the underlying randomness

« on: 06/06/2023 15:56:57 »

As I hope I have understood  Bell's theorem  has clarified the random nature of physical interactions (we do only have interactions rather than isolated events don't we?)

So if the random event is something of a ground zero in our understanding  of the physical world  what else can we say  about it aside from just accepting it and building on it?

Are we still allowed to believe that randomness  can still.be investigate to a deeper level of understanding or is this as far as things go?

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Physics, Astronomy & Cosmology / Are both electrons and photons modeled as excitations in a field?

« on: 10/04/2023 15:03:35 »

The photon is the force carrier of the em field (hope I got that right) and has no mass.


Is it considered as an excitation  in that field?

And what about the electron?Is it just an excitation  in the electric field?

So can both  massless and massive particles be modeled as excitations of their respective fields?

Hope I have not made too many basic errors in my question..

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Physics, Astronomy & Cosmology / Are fields and particles something of a chicken and egg story?

« on: 12/10/2022 15:18:13 »

So ,in QFT I hear that particles are excitations of their various  fields.

Would I be right to suspect that these fields arose in the earliest epoch of the known universe?

Could  the particles have "precitated" out of these fields as the fields expanded?(are they an integral if emergent  phenomenon attributed to those fields?)

Or could it be that the expansion of the fields, allied to an asymmetry  in them  led to "eddies" that came to manifest themselves as particles (excitations)?

Is this perhaps something that is not yet known?

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Physics, Astronomy & Cosmology / How big could the unknown universe be?

« on: 08/09/2022 15:41:41 »

We believe (with evidential proof?) that in addition to what we can observe by reason of its emitted light  there is a  (expanding?) region containing objects beyond.

If we take that as a given,are there any limits on the size of this area?

Suppose we give a  value of one to the volume of  the region we can observe  what  number could we assign to the region beyond?
2 ?  10? 10^100? Just infinitely larger?

Suppose  we assign the observable universe  the volume of a proton ,is it possible that the volume of the unobservable  universe  might be the same volume (or greater) than that of ,say the Solar System?

Is there perhaps  nothing, no estimation that we can make or do some models attempt to answer this question?

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Physics, Astronomy & Cosmology / If gravity is spacetime curvature ,is spacetime a field like gravity?

« on: 18/08/2022 23:03:18 »

Can we call spacetime a field or is it just a coordinate  system?

Do  all the local curvatures  of spacetime  constitute  a field?

If so ,is it possible to apply the description"an excitation  of the field" to this gravity/spacetime curvature  field and ,if so what would we be talking about?

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Physics, Astronomy & Cosmology / What would happen to the Solar System's gravitational connections if ....?

« on: 11/07/2022 14:19:13 »

What if the Sun became a black hole almost  instantaneously?

Suppose  we were living in a Solar System where the Sun was much smaller but equally  massive.

The planets were orbiting  this Sun in almost the same way  as in ours   and then ,one day the Sun tipped over into  a black hole for whatever reason ( not including the arrival of a foreign body but presumably  something that caused its radius to shrink )

In that scenario what would happen to    the orbits of the planets?

Would things continue as if nothing had  changed in that regard?

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Physics, Astronomy & Cosmology / How would we know whether space,time or spacetime were continuous or discrete?

« on: 11/06/2022 11:30:59 »

I understand that we have no answer as yet and my intimation  is that we may never know (although "we" may build a satisfactory model based on either supposition.)

In the meantime, what indications are there that one of these two paths might eventually bear fruit?

Is it all going to boil down    to some clever person devising an experiment that more or less rules out one of the options or  can some possibilities already be ruled out on the basis of existing understandings?

Suppose ,say one was investigating a possible discreteness, at what level might that be conjectured to occur -and would some mechanism be required to cause this or would  we reach the end of the chain of causality at that point?

(as an aside  ,does the thinking process have to follow the same laws and are our minds forbidden to imagine possibilities  at some deep physical level no matter how unrestrained our imagination can appear to us? Even imagination would be tethered?)

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Just Chat! / Is life built into the fabric of the Universe?

« on: 02/02/2022 15:11:01 »

Is/was life an accident  or an accident waiting  to happen?

Can we conceive of any universe (one with different "initial" conditions)  that would not ,at some stage evolve into a stage for life ,no matter how primitive?

Are there any theories that convincingly posit a universe of finite extent(both time and space) where it might be possible for life never to have evolved?

Or is this finite extent precondition  unconvincing?

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Physics, Astronomy & Cosmology / Anyone listen to Brian Cox's Universe on BBC4 ?

« on: 29/10/2021 13:16:57 »

Specifically where he seems to claim that the first stars were formed at the intersections of the filaments of Dark Matter.

Is this accepted and established science?

Apart from that I was quite impressed by his description of DM.Quite matter of fact  and no theatrics,in fact as if it was pretty well understood apart from not being observed with em radiation

Of course Dark Energy ,which hasn't  come up yet in his new series is a different kettle  of fish  and rather more startling imo.

Out of secondary interest I was going to post this on one of the other forums I post in ,scienceforums.net but one of the mods there  from San Diego,I think had a public run in with Brian Cox some years ago and it might have been a red flag to a bull
https://www.scienceforums.net/topic/64562-a-quick-glance-at-brian-cox-is-full-of-it/page/2/#comments

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Physics, Astronomy & Cosmology / What if the universe really is infinite?

« on: 18/10/2021 13:02:08 »

Watching a Horizon programme last night on BBC 4 (Sean Caroll was one of the contributers)

Apparently the Cosmic Microwave Background Map is like an expanding bubble around anywhere in our "neighbourhood" and its features have now been mapped in enough detail to "draw" a huge triangle from here to there.

The triangle ,according to the programme is evidence that  space (spacetime?) is probably flat and as a result the universe outside the observable part is  of infinite extent.

What might be the implications if this,startlingly  is true and can we now posit this provisional result as a stone to build our edifice of how "everything" works.

Can we ditch the "universe may be finite" for good unless we get  some new unexpected observations in the coming years or centuries?

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Physics, Astronomy & Cosmology / Is everything fundamentally quantum?

« on: 16/10/2021 13:58:15 »

Are there any classical behaviours that cannot be said  to be quantum to some degree?

Are there any theoretically possible tweaks to quantum behaviour  that would change the way the macroscopic  world would behave?

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Physics, Astronomy & Cosmology / Could mass be considered as an excitation of the gravitational field?

« on: 09/10/2021 15:54:40 »

Perhaps I am just regurgitating scientific jargon ,but might it be another way of looking at the relationship between mass and the gravitational field(which I think I may have told is not to be viewed as a physical object and rather a set a of measurements)

Anyway ,does my question have any merit?

Also,however defined , can we imagine the gravitational field to have been established in its initial form  after the BB and to be metamorphosing (changing shape) ever since

I think Einstein  may have used the "mollusk" description about it.

https://www.physicsforums.com/threads/what-einstein-meant-when-he-termed-something-a-mollusc.391139/

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Physics, Astronomy & Cosmology / Is the sequence of physical events continuous or discrete?

« on: 04/10/2021 00:14:03 »

Suppose I am washing my face some time tomorrow.

Within my body there will be many events occurring during that time.

I am no chemist but one might be that there is a reaction  between an atom of carbon and an atom of iron in my hand.

Whatever the particular reaction (and I assume there will also be reactions within that reaction) there will be a previous event that can be said to have "immediately" preceded or caused that iron/carbon event.

Will that earlier event be distinct from the (iron/carbon) event that followed or are these two events  connected in a continuous way?

I understand that particles are now modeled as being properties of an underlying field.Are these fields  believed to be continuous or discrete in nature?(in the model,I suppose I should say)

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Physics, Astronomy & Cosmology / How does the electron field get excited so as to produce an electron?

« on: 13/09/2021 15:47:30 »

I have been scratching my head as to how an electron creates an electron field.

Then I recall that it  the electron is considered as an excitation of the electron  field.

Then I recall that the field is just a  number of measurements (made with electrons?)

So what is is that  produces the excitation in the field?

Do these excitations  produce their own fields  ?Do these fields  add together  constructively and can they cancel out like waves?

And are these fields all in relative motion?

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Physics, Astronomy & Cosmology / What's the relationship between the speed of information and the speed of light?

« on: 29/08/2021 10:33:23 »

(for slow learners    )

I see  there have been  recent/ongoing interesting threads already and I doubt this is breaking any new ground ,even semanticly but here I go.

I have heard that the nature of speed of light in a vacuum   may be better understood as reflecting the maximum speed of transfer of information in the universe.

So is there any sense in which  light and information are joined at the hip?

Can information be transferred
without the mediation of a light signal? ( in either a practical or a theoretical sense)