1

Physics, Astronomy & Cosmology / Re: What is the exact cause of the time dilation of the twin?

« on: 28/11/2024 13:47:51 »

. Having never used supposed "AI"(no intention of doing so-you can't teach an old dog new tricks!), I am in a weak position to criticise. I have seen some atrocious rubbish in replies to questions posed by others and a high degree of suggestibility. In response to a question that requires a blunt "NO", answers will often digress into unsubstantiated speculation with the seeming aim of perpetuating the discourse rather than delivering a straightforward answer.

2

General Science / somethingRe: What Is Synchronicity?

« on: 23/05/2024 13:20:38 »

When something "appears meaningful" one is dealing with subjective effects as opposed to objective effects. As such no possibility of research into the alleged phenomenon exists. You more or less answered your own question with the reference to Jung's predilection for "magical thinking". In a word , no.

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Physics, Astronomy & Cosmology / Re: If Andromeda is red shifted how can we collide with it?

« on: 09/02/2024 19:16:01 »

Have I found an error here, Halc?(shock, horror). You state an object approaching an observer will be red shifted relative to a stationary case- surely you mean blue shifted?

4

New Theories / Re: How does Hamdani explain the twins paradox?

« on: 08/01/2024 22:19:07 »

... Because Craft is moving Forward ...

According to whom is the craft moving forward? You, at rest in it?

5

New Theories / Re: A Disproof of the Principle and Theory of Relativity

« on: 30/10/2023 23:19:45 »

Cross reference: https://www.scienceforums.net/topic/132749-a-disproof-of-the-principle-and-theory-of-relativity/

Thanks. In accordance with this rule:

It is not acceptable simply to post material onto this forum that you have posted elsewhere, except where the post is specifically pertinent to an ongoing thread.  If you start a thread with a post that is for all practical purposes the same as you have posted elsewhere, we will generally assume that you are evangelising, and will act accordingly.

This thread will now be closed.

6

Physics, Astronomy & Cosmology / Re: Which bit of the Shell theorem is not working?

« on: 19/10/2023 21:46:06 »

Hi.

   Yes I can see what you're saying @Halc .
I'm deeply sympathetic.   I don't suppose that will help.

Let's try and be a bit more useful.    You seem to be trying to do the impossible, so don't.
You discuss time dilation and gravitational potential.   Most of the results we have for that would tend to come from using the Schwarzschild metric in GR.    Around a massive spherical body, the Schwarzschild metric is a fair approximation of what you have and how spacetime behaves.    For that solution of the EFE (Einstein Field equations), the co-ordinate time is exactly as you have stated.   It is the rate at which clocks progress when you are infinitely far from the mass.
    After that you are generalising the result and imagining that time would always run more slowly in a region of lower potential than some other region you are comparing against.   It might, it does seem reasonable but we do not have the Schwarzschild solution applying across all of space.   We know the universe is not a vacuum around one spherical mass.

   Indeed there is a completely different metric that is often used when discussing the Universe,  the Robertson-Walker metric.    That is obtained as a solution to the EFE under a very different set of assumptions.   In particular the universe is not a vacuum, it's actually too much unlike any vacuum.  Nowhere is less dense than anywhere else,  the universe is filled homogeneously with whatever cosmological fluids you have chosen to have (matter, radiation, dark energy  etc.)    With the Robertson-Walker metric, time dilation does not happen when you move from one gravitational potential to another because   (i)  gravitational potential is ill defined anyway,   (ii) nowhere is any different to anywhere else, there is no place of different potential.    That is not to say that time-dilation isn't an effect you can observe at all, you certainly can.   Special relativity is automatic in the machinery of GR, so movement will cause time dilation.
    The time co-ordinate in the Robertson-Walker metric is not and does not need to be related to how time may flow when you are infinitely far away from all mass.   Indeed it turns out that there are lots of places in a FRW universe where time flows at the same rate as the time co-ordinate.   Provided a clock is co-moving with the expansion of the universe then it will progress at a rate identical to the time co-ordinate.
    The passage of co-ordinate time is not abstract, it is something that a real clock can measure.  There is no requirement to be in some special place, for example to be in a place with the lowest gravitational potential, or infinitely far from all mass.   For the Robertson-Walker metric, the co-ordinate time is not that.   

     There is a natural tendancy to blend the two metrics together and assume that our real universe will have properties of both,  with more of one in some places (close to a body the Schwarzschild metric prevails) than other places.
None-the-less it is an error to assume that the co-ordinate time used in the Schwarzschild metric is precisely the same as the co-ordinate time in the FRW metric,   or that either of these is precisely the same as the underlying co-ordinate time that our real universe with its real metric would use.   
   

The absurdity of trying to express this is one of my pieces of evidence against models with flowing time.

    Maybe a clock infintely far from all mass would progress infinitely faster than all real clocks in the universe.   That doesn't need to matter and it doesn't demonstrate the absurdity of time as something that flows.   The underlying co-ordinate time of the real universe and its real metric is probably not the thing that such a hypothetical clock in this hypothetical place is presumed to show.

Best Wishes.

7

Question of the Week / Re: QotW - 23.10.27 - Why is the sea salty water, but lakes and river are fresh?

« on: 19/10/2023 20:23:07 »

Fresh water bodies are supplied by precipitation which is close to pure water with negligible salt content. Rivers run into oceans carrying small quantities of various salts leached out from rocks. Water evaporates from the oceans leaving whatever salts are present in the oceans and the evaporated water then becomes precipitation to start the cycle over again. Over time this process has concentrated the salt in the oceans.

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New Theories / Re: What is non-returning twin paradox?

« on: 28/09/2023 22:33:18 »

Twin A finds twin B as younger than himself, hence he says that B experience time dilation.

No. While in relative motion they both consider/know that time is slow for the other. That's what is called "Time dilation".

And it goes both ways - it's reciprocal. After all, that is what puts "paradox" in "twins' paradox". (But to be clear, it's not actually a paradox, there's is no argument about that. The term comes from a naive partial understanding.)

On the other hand, Twin B finds twin A as older than himself, hence he says that A experience time contraction.

That one turns out a different age than the other is usually called "differential aging".

9

Science Experiments / Re: How many types of capacitance are there?

« on: 16/09/2023 22:13:11 »

Capacitance is simply the ability to hold charge, same as the volumetric capacity of an inflatable fluid container. Various methods of achieving this "capacitance" is what that wiki article is describing, NOT different types, as there is only one. Similarly one may find mention of self inductance and mutual inductance but there is only one inductance.

10

Physics, Astronomy & Cosmology / Re: Does helium make all sounds higher pitched?

« on: 03/09/2023 21:08:41 »

I don't think so, Kryptid. The resonant frequency of the glass is determined by the physical properties and physical form of the glass. The larynx relies on gas properties, a bit like an organ pipe. Have look at organ pipes and how they work, with open and closed pipes influencing the frequency. There might be some slight effect with different gases.

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Physics, Astronomy & Cosmology / Re: How do we know that particles are entangled?

« on: 27/06/2023 18:53:26 »

How do they know that the spins of each electron were not predetermined when they were entangled. 

Bells inequality.

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Chemistry / Re: Why Choose Full Lace Remy Hair Bundles?

« on: 11/06/2023 19:50:59 »

Hmm...how did sxgrt know about the Spam Link?

Links were Removed from the OP's original message.

But when sxgrt Quoted the OP post, the Spam Link is right in there.

How's that Possible?

13

New Theories / Re: A Quandary about Accelerated Motion in Special Relativity

« on: 24/04/2023 17:01:22 »

Hi.

   OK, we can see the diagrams you ( @MikeFontenot ) have posted.    We can also see that you have drawn some diagonal lines between the two worldlines.

   So I'm going to agree with previous comments from others.   The situation is very much like Bells's spaceship paradox and it is probably best explained just by looking through a good explanation of that situation ("paradox" - although it isn't really a paradox, a perfectly fine explanation does exist).

     I'm, not sure that the link to Wikipedia's article provides a great explanation.    Try this explanation:
https://math.ucr.edu/home/baez/physics/Relativity/SR/BellSpaceships/spaceship_puzzle.html
    (That's a physics  FAQ  webpage  from the University of California and should be safe enough).
I've noticed that their diagram and explanation has the same approach of drawing diagonal lines from one worldline to another (lines of constant time or of "simultaneity" in a different frames of reference).    I think it will help to remind you of what was actually done in your own diagram and answer many of your questions.   Obviously they have chosen to put time on the y-axis and not the x-axis but other than that switch it's showing exactly the same as your diagram.   

    The phrasing of these situations is always complicated and English Language is rarely the best tool to use,  diagrams really help.   The phrasing used on their  ( ucr) webpage isn't without some problems but it's a good effort and I doubt I could do much better.     Notice that they do end the discussion with a digram showing a very different pair of worldlines the objects could have traced out in the lab frame  (the one you called IRF in your posts),  where the people in the rockets now would find that the distance between the rockets remains constant - but the person in the lab frame no longer does.

A new question: Do the two observers who are doing the accelerating agree that their separation is decreasing?

    If you manage to follow the explanation of Bell's spaceship paradox you'll see that the answer is  "no",  not if the objects have the worldlines with the shape you've given them.   The distance also doesn't decrease as you stated, they would notice the distance has increased.   

Best Wishes.

14

New Theories / Re: Biblical Flood

« on: 04/02/2023 21:11:37 »

My theory predicts PE2 particles (anti-protons) should be unstable in a positively charged universe.

Well then your model has been falsified, as antiprotons are very much real.

Since you have ignored my last post yet again, and you were warned about it, this thread is getting closed. Don't open a new thread about your model or it too will be closed and you will be suspended for trying to bypass a thread locking.

15

Physics, Astronomy & Cosmology / Re: Does time have more than one direction?

« on: 12/12/2022 04:51:25 »

Hi.

Some of the formating of quotes has gone wrong in your last post. So I'll just use something sensible here:

ES said:   How long did you take to come up with that?
Halc replied:  Quite some time ago, when first asked how to point in the 4th direction.
   The original comment was about the time axis and was sufficiently inspired it's worth repeating here:

The time dimension is like that. You pick two events (points in spacetime). You say 'this' event and clack two rocks together to define the event.  Then you wander off some arbitrary place and clack the same two rocks a 2nd time to define a second event. The one unique line through spacetime connecting those two events is now defined. You've chosen a totally arbitrary orientation for your time dimension since the two events you chose are completely arbitrary.

   
   Now, I did mention in a post some time that it was "more or less" correct.   I'm just going to discuss the "less" part here because the "more" part speaks for itself, it's an amazing way of describing how you could choose a time axis.  So, there's genuinely no offence intended.  You've obviously spent some serious time replying to @Dimensional and might just want a little feedback or something to think about.

   Let's start by considering a person, we'll call her Roxanne ("Roxy") because she's the one who will be doing the rock clacking.   Now Roxy starts by clacking some rocks at  x=0, t=0 in whatever co-ordinate system she was originally using.   Supposedly, Roxy can clack more rocks at any arbitrarily chosen event in spacetime.  Let's say she clacks the rocks at the event   x=10, t=0   in her original co-ordinate system.   So that's just two events that were at the same co-ordinate time and just lay along the x-axis of her original co-ordinate system.....   do you see where I'm going with this?
    The spacetime interval between those two events =  +100   (in a suitable convention with  ΔS² =  Δx² - c²Δt²),  in particular they are most definitely spacelike separated.  Moreover, the spacetime interval is a conserved quantity under any Poincare transformation we apply.  So whatever new co-ordinates t'  and x' we try to generate,  we will still have    ΔS² = +100 = (Δx')² - c²(Δt')² .   It's the being positive thing which is the real sting in the tail.  The two events remain spacelike separated.   In particular there is no way those two events can lie along the new t'  time axis.
   More generally, the two events with the rock clacking can't be completely arbitrarily chosen,  the first one is arbitrary.  The second one must be timelike separated.
   **Also,  Roxy is only metaphorically allowed to "wander off" to the other rock clacking event.  Since that event must be timelike separated from the other one, she has to run faster than anything else in her world.  That's not too bad though, there doesn't need to be a Roxy and even if there was she was only metaphorically wandering off to the other event.**

Best Wishes.   

**LATE EDITING:  I've already spotted that the last paragraph was backwards,  Roxy can't get to spacelike separated events but timelike is no problem.   I've left the error in because we're all human.  **

16

New Theories / Re: Gravitational Arm

« on: 16/11/2022 12:59:11 »

THANKS
So you fully confirm that one spiral arm which is connected to the other galaxy is due to gravitational attraction.

Do you fully confirm that this simulation shows that using our current theories a stream of stars between interacting galaxies is not a surprise?
https://svs.gsfc.nasa.gov/10687

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New Theories / Re: Gravitational Arm

« on: 16/11/2022 06:05:05 »

However, once one spiral arm had been frozen by gravity force to the other galaxy

It isn't. Gravity isn't freezing anything in place here. It's like saying something in free fall is frozen in place. It's not. This tidal tail is a temporary structure.

18

New Theories / Re: An Offer I Made to Utrecht University in the Netherlands

« on: 19/10/2022 17:00:00 »

This poster has repeatedly ignored moderator requests to:
-  keeping to topic and not ranting.
- not reopen a closed thread
- post only in New Theories section

This topic has been previously published elsewhere by the op, however we cut him some slack to allow discussion and defence of his ideas, but he has now resorted to more off topic rants and has also used non-family friendly language.

He also needs to note that his maths has been commented on by @Halc who is to be commended for taking the trouble to answer a very confused piece of pseudomaths which demonstrates very poor understanding of both the maths and physics by the op.

For the above reasons this poster is now banned.

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

« on: 14/10/2022 00:38:02 »

Hi.

I've seen discussion of how there were not distinct fields at first, and gravity separated out first, followed by other forces/fields.

    Yes,  that's OK.   I've seen similar discussions, usually focusing on the fundamental forces and when they begin to separate as temperature and presure falls in the universe.
     I had the impression that all the fundamental forces were always there,  it's just that some were indistinguishable.    To say this another way, the original one big force was always four individual forces added together but they all behaved the same way.   So, there was in effect just the one big unified force.   This is different from saying that some forces were not there at all.  This could be a matter of semantics or personal preference but since it's a quiet day, I'm going to keep pushing the point.   

    Example:      You have a stack of  4 bricks on top of each other,   this height or the total stack is the value of the original grand unified force.   Later on the bricks cool down and you can start to see that there are differences between the bricks:  The yellow ones are water-proof,  the red ones are harder, the green ones are spongy.  That's how I imagine the situation:   All the forces were always there, you just couldn't distinguish between them.

    To put this on a more secure mathematical footing:    There should be one Lagrangian describing the system   (the whole universe),    the one commonly used for the standard model of physics as derived from QFT is shown on this t-shirt:

Lagrangian tee.png (184.14 kB . 428x411 - viewed 1621 times)
   (The details aren't important  AND indeed this is still thought to be just an approximation.  It's a low energy approximation -  a good approximation for the Lagrangian at sensible temperatures etc.)
   Note that the standard model Lagrangian is just the sum of components, where each component is usually identified as being due to ... a photon field component, Higgs components,.... etc. etc.   
     Anyway, assuming the universe can be described with a Lagrangian then there is no reason why the Lagrangian would suddenly be thrown away and a different Lagrangian used at high temperatures or pressures such as close to the time of the big bang.   However, many of the terms within each component can and do conceal expressions like   (1/T)   where   T is the temperature.   So as  T ---> hot   then these terms -->0.   The disappearance of these terms results in the properties of what was the electromagnetic field becoming indistinguishable from  those for the nuclear Weak force   etc.       Anyway,  that's my take on it.    The Lagrangian can't suddenly be a different Lagrangian at early times,  it should really be just the one Lagrangian all the time.  Just because you can't easily identify one component from another at high temperatures does not mean that they were not there,  they were just a portion or fraction of the force you can find.    (This is very informal, with many simplifications,  for example not all the interactions or forces have a simple numerical value which you can just divide up into fractions,  some interactions are described with rank n tensors instead of single numerical values).

Best Wishes.     

20

General Science / Re: Are space and time just two sides of the same coin?

« on: 03/07/2022 16:59:06 »

Might be time to take a pause and look at some basics here because I think there are some misunderstandings.

Minor point. Ideas generally come before models, but not always. Take eg of Copernicus, before him the idea was that the sun orbited the earth. The top mathematicians of the day, the Arabic scholars, struggled to find a model that worked with this idea. Copernicus came up with a different idea, that the earth orbits the sun from which a model of the planetary system could be developed.

Perhaps you're still convinced that movement needs a time dimension to facilitate it but are unwilling to stand up for your conviction. 

That depends what you mean by dimension and what you mean by facilitate.
Physics defines seven primary dimensions: length, mass, time, temperature, electric current, amount of light, and amount of matter. I suspect you would only consider one of those to be a dimension, that’s because the common usage of dimension is very different from the physics usage.
Facilitate movement? Certainly we know that any movement has a start position and time, and an end position and time (physics calls these points events and there are an infinite number of such events between start and finish). Whether you consider time to facilitate that movement is debatable, but I would say not. For example, we measure the temperature dimension, but it would be unusual to suggest that the dimension facilitates temperature. Temperature is facilitated by other causes, we just measure the effect.

The idea that there is a past, present and future is speculation when all we know is the present. I remember where objects were before they moved (past), and I can predict where objects will be after they move (future) but memory and prediction of movement is far from being evidence of a time dimension. This is a mistake and one that is rearly admitted.

I’m not sure who you think rarely admits it. I would agree if you are talking about the general population, but physicists (and philosophers) frequently debate this area. Your view is a form of temporal presentism, but there are many other options including block universe. So, you have nailed your colours to a particular wall, some would agree with you, but there are others who would say you are wrong to do so.
I tend to think in terms of a dynamic view of time. Do I believe that somewhere in spacetime Anne Boleyn is still being executed, or WWII is still being acted out, no. However, I would never be as arrogant as to say that my view is correct and all other views wrong.
@Halc has probably looked at all the different philosophies, but I suspect your accusatory tone might have put him off further discussion.

…….as long as you remember they are just imaginary.

Imaginary has a different meaning in physics to common usage. It does not equate to not real, as in unicorns are not real.

I understand you for some reason don't like that time is a dimension,

Pesky empirical evidence.

If you can devise an experiment that will provide unequivocal empirical evidence of your idea, then you will be in line for a Nobel prize. The reason there is so much debate and varying views in this area is because there is no empirical evidence.
There is, however, a lot of evidence that our common sense view of distance is affected by relative movement, and that what is the past for me might in some circumstances be the present for someone else. Distance is also affected by gravitational potential, so 2 people at different heights above the earth could disagree on vertical measurements.
Experiments in particle accelerators also tell us that distance is not what our ‘common sense’ might suggest.

I want to meet you at Joe's in 10 unicorns, of course we will have to set up a convention for one unicorn like the swing of a pendulum or the movement of the sun, however we won't need to set up a convention for the spatial dimensions because they actually exist and we can measure them directly.

As Origin points out, you are confusing units with dimensions.
Hours and unicorns are units and arrived at by convention, so are distance units.
Also, there are many things we cannot measure directly, but that doesn’t mean they don’t exist.
Interestingly there are many people who have a very good sense of time and can tell to within 15mins what time it is, and musicians have a very good time sense otherwise there would be no consistent rhythm.

All in all this is quite a complex subject, but I’m glad you are taking the time to think about it.