Mordred

7 minutes ago, jv1 said:

Thank you so much externo 

This helps a lot

 

Not if you want mainstream answers. There is no ether in mainstream physics

33 minutes ago, externo said:

In a light clock the speed of light is invariant with respect to space but certainly not with respect to the light clock. You are confusing the invariance of the speed of light with respect to space or ether which is Lorentz's postulate and the invariance of the speed of light with respect to all inertial frames which is Einstein's.

The speed of light remains invariant to all observers that is precisely what invariant means.

The confusion is on your end 

7 minutes ago, externo said:

If time dilation was a relative effect, it would not be absolute and the twin would not return younger.

If the speed of light does not change relative to a moving object, how does a light clock work?

It is the measurement of the speed of light that does not vary, not the speed itself. Meters and measuring standards are transformed in such a way that they always measure the same round-trip speed.

Precisely time is not absolute.  If that's what you believe you need to catch up to modern research.

1 hour ago, externo said:

You are confusing time dilation and simultaneity. 

The change in simultaneity is the origin of length contraction and is a perspective effect. Time dilation is an absolute effect and comes from the decrease in the average speed of light relative to an objet in motion.

No I'm not I know precisely how SR and GR works including the related math. I use it all the time as a professional physicist.

Here is a challenge for describe at point between two observers in different reference frames where simultaneaty can be said to occur.

Then add a third observer 

5 hours ago, md65536 said:

I've seen this posted on this site many times over the years and I think it's wrong but never saw a correction or explanation. It's repeated often in posts labelled "expert" but I don't understand what it means. As a Lorentz transformation doesn't a boost imply constant velocity? How can a measure of velocity be called an acceleration? How is a measure of velocity a type of Lorentz transformation?

Is there some sensible meaning to what I quoted that I'm just not comprehending?

Both velocity and accelerations are boosts in the the Lorentz transforms. Rapidity is just a particular type of boost. I know you and I had tried discussing this in the past. Later on when I'm not at work I will try to get you far better detail on the difference of a boost due to velocity as opposed to acceleration. Part of the confusion  is that both velocity and accelerations are also described by rapidity. However the transforms for each slightly  different .

I doubt using a laser from Earth regardless of how powerful would be of much use. Ideally you would want to use the laser on a side perdendicular to its trajectory. If you fire from Earth you would thr asteroid head on and outgassing wouldn't be as useful.

36 minutes ago, externo said:

 

you can see that there is a "simultaneity jump"

Its in Lorentz theory you have to disentangle what you observe from what’s happening with the clocks, in Einstein's theory what’s happening with the clocks is considered physical reality, it's the only way to explain the constancy of the speed of light, or else this constancy itself is not physical reality and then it's no more Einstein interpretation but Lorentz.

If time is not physical, neither is Minkowski space-time and Lorentz is right.

It would really help if one understands a physics theory correctly before you try to interpret a theory. It's rather pointless otherwise. 

Anyone that understands relativity by knowing what the mathematics of the theory states. Simultaneaty is of little use in this case as it's coordinate dependent. This is due to time not being constant.

For example an observer looks at his watch. However that's simply his coordinate time. The other observer does the same for coordinate time. Due to time dilation regardless of whether it's due to gravity or inertia his clock will appear to run normal. However once you compare clocks then the difference is noticed. 

 The two clocks are no longer simultaneous welcome to relativity and it's time dilation 

2 hours ago, externo said:

You are talking about mathematics, this mathematics was discovered by Lorentz, Poincaré and others, and accounts for observations. I talk about the physical interpretation of these equations, and I show that Einstein's interpretation does not work. You are trapped in the idea that the accuracy of SR's mathematical equations necessarily validate Einstein's interpretation. There is no doubt that Lorentz's interpretation works because it uses classical kinematics, but Einstein's interpretation uses a anomalous kinematics that must be proven consistent with the physical world.

Look at this:

https://en.wikipedia.org/wiki/Talk:Twin_paradox/Archive_5#GR_section_removal

The GR section of the twin paradox has been removed from Wikipedia because it is invalid.

On the other hand, at the end of the article you have a section which explains that the paradox disappears if we assume a privileged frame of reference as in Lorentz theory :

https://en.wikipedia.org/wiki/Twin_paradox#No_twin_paradox_in_an_absolute_frame_of_reference

Wiki isn't written by a physicist. It has zero authority in the physics. 

 Any discussion involving physics to have any use whatsoever must always include the math. It's rather useless to discuss interpretations of any physics theory without knowing what those mathematics actually describes. 

You know it's funny to declare GR cannot solve the twin paradox when it's in nearly every textbook on GR. Acceleration is easily handled in both SR and GR. It's simply a type of boost called rapidity. You can alternately use instantaneous velocities. 

So really it's a poor defense for a theory Long shown inaccurate specifically the Lorentz ether theory. Particularly since it ties into Lorentz invariance which current tests is something of order of 1 part in 10^(18) for any deviation on the constancy of c. That is rather conclusive for any potential of any ether based theory being viable. Yes I've read lots of attempts to salvage LET over the years including professional written articles and examinations none of have ever born out though. I even have copies of those various models. Though it would take time to search for them.

4 hours ago, ImplicitDemands said:

The cmb is sending light through a cone but the galaxy's actual position is about a half sphere

When I'm in the mood 

That comment makes no sense but so far without seeing your math. Nothing you have stated makes much sense.

The CMB is literally everywhere in our observable universe you can even hear it's static on older radios that don't filter it out.

It may surprise you to know that expansion has little to do with gravity but rather it's due to thermodynamics via the equations of state for each particle species.

https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology)

If you take a uniform mass distribution and apply Newtons Shell theorem gravity is zero.

6 minutes ago, Prajna said:

There were very helpful comments today.

Hence why I stopped adding to the mix. Once I saw you were progressing from their comments I didn't want to add any potential confusion. Threads can get too easily derailed.

1 minute ago, Prajna said:

Thank you. Anyway, I hope there's nothing stopping me being able to do it tomorrow.

No you get a daily allotment 

6 hours ago, Prajna said:

Excellent analysis, both of you.  Sorry, I have no more reaction points available today or you'd both get a +1. This is exactly what I came here to explore. All I have to do now is re-read both comments carefully to make sure I understand. Thanks.

I gave them the +1 each for you.

7 hours ago, dimreepr said:

I put my faith in 'The Avengers', sorry couldn't resist; essentially it's all about the ETA, so our best defence is keeping our eye's peeled...

I have to wonder if that would be effective, by the time a focused enough beam to make a difference, had any effect, it seems to me that it would probably be too late to make a real difference.

Depends on the asteroid composition. The usefulness of a laser is to generate outgassing. For example an icy asteroid if you shoot a laser at it would more readily generate water vapors which would then provide thrust.

The first relativity never used the ether for the observer nor the emitter.  It used the ether to describe how photons travelled between the two prior to proving ether wrong through the Michelson and Morley experiments.

Those experiments are far far more precise in modern tests. Either way if you look at SR the emitter isn't ether and the observer isn't ether. 

Nor did Galilean relativity which the Lorentz transforms is simply an extension of (the Gamma factor constant of proportionality) 

3 hours ago, externo said:

Einstein's relativity is based on the idea that it is always the observed object that moves relative to the ether and not the observer. If we prove that it is the observer who is moving relative to the ether we invalidate Einstein. Lorentz says that the observed and the observer can both move relative to the ether

The relativistic Doppler effect contains time dilation so if the Doppler effect comes from the one accelerating, time dilation can only come from him too.

You cannot resolve the paradox with Einstein's SR, if you believe you do it it is because you are using Lorentz theory, as the mathematics is the same you cannot decide with them. 

Everything in this post tells me you never  actually studied the mathematics yourself. Had you ever studied the mathematics You would know Neither theory uses Ether. Nor does it uses the ether for a observer or relative to.

Your claims is not what either theory states. Each frame of reference is emitter /observer relative to each other not the Ether.  So forget thinking Ether is involved in either theory. That is absolutely incorrect 

As I mentioned you would need the math to show this. You keep mentioning your math so you should already have the math handy for us to examine.

I can easily show you all the mathematics behind the FLRW metric but that wouldn't help determine why you have an issue with it.

If it's an issue with not knowing how to latex the math in let me know and I can demonstrate how our format uses \[\frac{1}{2}\,] I placed a comma in the last part to prevent it from activating. Your description of using spheres for example tells me you should have a spherical coordinate system with some constant of proportionality for the scale factor  however that's based on your description. I need your math for confirmation.

37 minutes ago, Prajna said:

Sorry, I don't understand. Unless you mean it's a win that I'm belatedly reading about magnetism and you don't need to be involved in analysing the device.

By the way, I stumbled back on the article about monopoles, for anyone interested, it was in Popular Mechanics: https://www.popularmechanics.com/science/a60079037/magnetic-monopole-hematite/

Monopoles is an interesting study for example it's potential would fall off at 1/r as opposed to 1/r^2 for dipolar, 1/r^3 for quadrupolar ie the combination of two dipolar fields. As opposed to quadrupolar in gravity waves. 

 Boit-Savant law can be uses to solve for the above if I recall.

3 hours ago, externo said:

Is Einstein's theory of relativity able of solving the twin paradox?  

Absolutely both SR and GR are able to solve the twin paradox. The paradox wasn't due to any lack of ability of either SR or GR. They both have the same transformation rules.

The paradox arose in SR simply because of the constant velocity treatment which was incorrect. Take the acceleration into account and both SR and GR will get the same answer.

Fundamentally the only real difference between the two is GR is better suited for field treatments and handles curvature terms better. The other difference is that in GR there is no "at rest observer" . 

Both SR and GR use the same transformation rules. They both employ the Minkowskii metric though in GR the Minkowskii metric is used in the weak field approximation.

\[G_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}\]

Both are part of the SO(3.1) Poincare group.

As they  both use the same Lorentz transformation rules claiming one is incorrect while the other is correct is in error.  Let's put it another way the solution to the twin paradox is identical in both SR and GR when correctly done 

You might try including the math you speak of. First off you seem to have missed the detail that spacetime curvature vs flat directly describes the null geodesics of massless particles such as photons through spacetime. Hence we can test the curvature term by looking for distortions in the CMB.

My favorite method requires early detection take your spacecraft and instead of trying to trap it in a net. Which as mentioned isn't practical. Simply maintain distance from the asteroid and let gravity do its thing. Use the spacecraft plus the gravitational interaction between the two divert the asteroid to a new vector path. The further away you can do this the less change in vector angle that would be required for a miss.

On 4/16/2024 at 8:34 AM, swansont said:

Magnetic forces don’t do work. 

I would like to touch a bit on this using Maxwell equations but also Lorentz force law divergence and curl of the Electrostatic field 

Gauss Law

\[\nabla \cdot=\frac{1}{\epsilon_0}\rho\]

\[\nabla \times E=0\]

magnetostatic Field

Amperes law

\[\nabla\cdot B=0\]

\[\nabla \times B=\mu_0 J\]

Lorenz force law with Maxwell for the presence of both the E and B field (Maxwell equations fundamentally is another way of stating Biot-Savart Law (with superposition) just a side note.

\[F=Q(E+v\times B)\].

so the electric field diverges away from a positive charge, (Gauss law) the magnetic field curls around a current (Amperes law). Electric fields originate form a positive charge and terminate on a negative charge. Magnetic lines do not begin or end anywhere and form closed loops as they have zero divergence. (though divergence can be forced). There is no point source for B ( not unless they ever discover magnetic monopoles lol). Now something interesting to note the magnetic field specifies an electric current.( A permanent magnet induces an electric current). So with the 90 degree phase shift between E and B using the right hand rule for Lorentz force law. The following statement applies.

The magnetic field does no work....

so take for example a magnetic crane the work isn't performed by the magnetic field but rather the electric field as well as the cranes mechanical energy.

This is something that isn't well known among laypersons unless they studied introductory electrodynamics and the Maxwell equations. Hence why I decided to mention it here as its related.

The above is better detailed in Griffiths "Introductory to Electrodynamics". I've found his simplified approach useful as a reference in many of his books.

4 hours ago, Prajna said:

Ah, ok, you were talking with regard to the device and I was (at that time) talking with regard to the thought experiment. Cross purposes, sorry for the misunderstanding. Yes, I'm sure that at some point I will need to consider distortion in the fingers/tabs but engineers often just over-engineer things, add s fudge factor, rather than fuss about such details. This particular design is just a proof of concept and the objective was to make it easy for people to grasp the principal of operation. The rotor is designed so that the number and geometry of the tabs can be changed easily in order to test different configurations.

 

No problem, it all depends on how detailed or how far you choose to pursue the concept. One thing to consider however is that in order to look at stress and stain aspects. You require the force/work terms as well. For example far too often I've seen perpetual energy  articles discussing some popularized perpetual device use nothing more than first order equations. 

However when the same setup gets examined using second order relations by others that the energy loss is found exceed the output power.

As Swansont mentioned in physics one cannot arbitrarily choose to ignore this interaction (in this case different forces) or that but should take everything in consideration. Stress tensors are particularly useful in that as all forces are applied with a means of keeping track via the tensors regardless of angles.

Not saying perpetual energy is involved here however the above is also useful for efficiency calculations.

We cross posted see my last post 

1 hour ago, Prajna said:

 

Did I say the area of the plate was  I'm not. I'm talking about a SMALL plate of metal being ATTRACTED to a magnet that is in a fixed position. 

Look at your own image is not the rotor plate larger than the magnets and the placement off center ? 

Now am I correct those magnets will be shifting inward and outward ? So as it shifts outwards as opposed to inwards you will get variations