Speed of Light and Energy...?

[Farsight]

If the photon executes a hubius helix any translational movement is bound to push it above c at some point on the helix?

Not at all. The photon is still moving at c, but it takes longer to complete one revolution because it's got to traverse the lateral component as well as the circular component. Don't pay any attention to that link you found, that was just a string theorist throwing mud.

[Farsight]

What happens to e = mc squared, in relation to a massless particle?

There's a more complete expression E² = (mc²)² + (pc)² which deals with moving particles, p being momentum. You can find it on http://en.wikipedia.org/wiki/Mass%E2%80 ... quivalence. However the photon is massless so the expression reduces to E² = (pc)². After pair production, if you ignore the motion of the electron, a flip has occurred, and there's no momentum. Hence the expression is now E² = (mc²)², which is just E = mc². After annihilation it's flipped back to E² = (pc)². I was talking about mass earlier to oddmanout on another thread, see http://www.rationalia.com/forum/viewtop ... 75#p432549 for details. There's a symmetry between momentum and inertia.

[newolder]

...
Newolder, I recommend you read Zeptospace Odyssey: A Journey into the Physics of the LHC by Gian Francesco Giudice where on page 174 he says "It is sometimes said that the discovery of the Higgs boson will explain the mystery of the origina of mass. This statement requires a good deal of qualification". He then goes on to say that the Higgs mechanism is responsible for 1% of a proton's mass. He's a bona-fide guy, quite high up at CERN.

Thanks for the link but I'm in no position to buy any more books. How do you square this 1% with your earlier posts to me (at rd.net, iirc) where you were adamant that the Higgs mechanism plays no part and the lhc will not find anything related?

[colubridae]

Squaring the circle.

[mistermack]

What happens to e = mc squared, in relation to a massless particle?

There's a more complete expression E² = (mc²)² + (pc)² which deals with moving particles, p being momentum. You can find it on http://en.wikipedia.org/wiki/Mass%E2%80 ... quivalence. However the photon is massless so the expression reduces to E² = (pc)². After pair production, if you ignore the motion of the electron, a flip has occurred, and there's no momentum. Hence the expression is now E² = (mc²)², which is just E = mc². After annihilation it's flipped back to E² = (pc)². I was talking about mass earlier to oddmanout on another thread, see http://www.rationalia.com/forum/viewtop ... 75#p432549 for details. There's a symmetry between momentum and inertia.

When it comes to momentum, my problem has always been with some aspects of relativity. If energy is real, and eternal, can't be created or destroyed, I can't get my head round how it can be relative. i e , two objects moving towards each other. Does one possess the momentum, or the other, or do they both possess part of it? If energy is a real uncreateable indestructable entity, then to me they must each have an actual momentum, not relative momentum that you can flip from one to the other just by choosing different imaginary axes.
And that means that the Universe has to have a fixed frame of reference, that everything moves relative to.

[colubridae]

You don't like it that's fine. You would be insane if you did.

It's not meant to be a loving picture of kindness and god and stuff.

Demonstrate where the theory is wrong.

[mistermack]

I'm not sure if you were adressing me. But if you were, then I was attempting to do just that. If you can create and destroy kinetic energy, just by choosing different frames of reference, I was saying there is something wrong somewhere.
I was hoping someone would point out what was wrong with my reasoning.
Kindness and Gods don't enter into it.

[hackenslash]

When it comes to momentum, my problem has always been with some aspects of relativity. If energy is real, and eternal, can't be created or destroyed, I can't get my head round how it can be relative. i e , two objects moving towards each other. Does one possess the momentum, or the other, or do they both possess part of it? If energy is a real uncreateable indestructable entity, then to me they must each have an actual momentum, not relative momentum that you can flip from one to the other just by choosing different imaginary axes.
And that means that the Universe has to have a fixed frame of reference, that everything moves relative to.

This is an interesting question, and one that goes to the heart of relativity. This is one of the hardest, and yet the simplest, of concepts to get your head around. To answer it, we have to go to what motion actually is. I'll start with a possibly counter-intuitive one that actually comes from Newtonian mechanics.

In this instance, the important law is Newton's third law. Often stated as 'every action has an equal and opposite and equal reaction'. What this means in reality is that, for example, when you jump up, the Earth moves down. That is the bit that is counter-intuitive, but it's actually pretty obvious if you think about it. The Earth doesnt' move by much, given the difference in mass, but it does move.

Now we have to move this to a relativistic frame and see what the same action gives us. When you jump up in this manner, in a relativistic setting, it is equally true to say that you jumped up as to say that you pushed the Earth down. Indeed, because relativity says that each observer has an equal claim to being at rest, it is exactly equivalent to say that you jumped up as to say that the Earth moved down. So the same energy is imparted into the system whether you say that you jumped up or you say that the Earth moved down. In short, the energy imparted is the same regardless of which perspective you take.

As for what everything is measured against, it is measured against the only reliable constant of the universe, namely the speed of light. This is the only constant, and the reason for this is given throughout this thread. That is the only frame of reference that everything moves relative to.

[Twiglet]

When it comes to momentum, my problem has always been with some aspects of relativity. If energy is real, and eternal, can't be created or destroyed, I can't get my head round how it can be relative. i e , two objects moving towards each other. Does one possess the momentum, or the other, or do they both possess part of it? If energy is a real uncreateable indestructable entity, then to me they must each have an actual momentum, not relative momentum that you can flip from one to the other just by choosing different imaginary axes.
And that means that the Universe has to have a fixed frame of reference, that everything moves relative to.

The speed of light is not like other speeds

You can always go 1 mph faster, and never reach it. In fact, if you hold a torch in front of yourself and walk forward 1mph faster, and measure the speed coming out of your torch, it will always be the same, even if you walk 1mph faster after each measurement.

What's more, someone who is standing still where you started, and also measures the speed of light coming from your torch will ALSO get the same speed as you.

Compare that to the classical picture.

Imagine you throw a ball and start walking towards it 1mph faster than when you threw it. If you threw the ball at 5mph then walk towards it at 1mph - it will appear TO YOU - to be moving away from you at 4mph. Your friend who is sat still will say it's moving away from him at 5mph.

That's the inherent wierdness of relativity. It "seems" very superficially easy to say "c is the fastest speed" then ask why you can't go faster.

No matter yhow fast you run towards the light from your torch, it will ALWAYS be moving away from you at the speed of light, unlike the tennis ball you threw, which you can catch just by speeding up to 5mph.

[Twiglet]

The second question is very interesting. Is Kinetic Energy "relative", and if it is, how can Energy be conserved, especially if all frame of reference are equally valid.

Lets initially ask that question classically, because it's just as valid a question in purely Newtonian terms.

If I stand still, holding a ball, and I throw the ball, it moves away from me at v, and has KE of 1/2 mv^2. Pretty straightforward, right?
Lets for a minute - to make life easier, assume that I am in space, in a vacuum, without any gravity affecting me, and my mass is M.

When I throw the ball, momentum will be conserved, so in throwing it forward, I in turn will move backwards. If i was on Earth, I would still recoil, but that would be absorbed into the earth via friction, creating heat and sounds and maybe tearing up the grass under my feet a little bit.

In space, MV1=-mv so v1 (the speed at which I recoil) would be (m/M)v, so my KE would be 1/2Mv1^2=1/2mv^2 - wow!

conserving momentum means that the KE imparted to me in throwing the ball is identical to the KE of the ball itself, purely by application of the conservation of momentum.

__________

Imagine, for the sake of example, that you have been watching all this happen, and were yourself moving away from me at speed Q to start off with.

As far as are concerned, my original energy would be the combined mass of me, and the ball x 1/2Q^2

i.e. 1/2(m+M)Q^2

How much energy would you see after I have thrown the ball. To be consistent with conservation of energy the answer would need to be 1/2(m+M)Q^2 + 1/2mv^2 + 1/2Mv1^2
because we have established that from the original frame of reference, 1/2mv^2+1/2Mv1^2 of energy has been added.

This would prove that extra energy has been created, classically, by the act of throwing the ball.

Energy of ball, relative to observer= 1/2m(Q-v)^2
=1/2m (Q^2-2Qv+v^2)
=1/mqQ^2 -Qmv + 1/2mv^2

My energy=1/2M(Q+v1)^2
substitute v1 from earlier calculation: v1=(m/M)v
Energy= 1/2M(Q^2+2Qvm/M + (m/M)^2v^2)
= 1/2MQ^2 +Qvm + 1/2 m^2/M v^2

Sum the pair:

Note the Qvm's cancel each other out

1/2 (m+M)Q^2 +1/2mv^2 +1/2v^2 (m^2/M)

we know v1=m/Mv so the last term. 1/2v^2*(m^2/M) simply becomes 1/2Mv1^2 by substitution

Meaning the total energy in the observers frame of reference is:

1/2(m+M)Q^2 + 1/2mv^2 + 1/2Mv1^2 which is exactly what we wanted.

[colubridae]

I'm not sure if you were adressing me. But if you were, then I was attempting to do just that. If you can create and destroy kinetic energy, just by choosing different frames of reference, I was saying there is something wrong somewhere.
I was hoping someone would point out what was wrong with my reasoning.
Kindness and Gods don't enter into it.

If I seem rude I apologise.

The others are much better at explaining and know much more than me.

I would trust their answers.

[mistermack]

If I seem rude I apologise.
The others are much better at explaining and know much more than me.
I would trust their answers.

No problem, I didn't intend that to sound 'huffy'. I really wasn't sure if your post was to me, or someone previous.

Yes I appreciate twiglet and hackenslash clarifying it. My problem is accepting it, more than following the reasoning.
That's why children learn faster, they accept things more readily, even if they sound illogical.
That's why the religions like to start on them when they are very young.

Hackenslash wrote that the speed of light is the only frame of reference that everything moves relative to.
Is that strictly true? I wouldn't call it a frame of reference. It's an unvarying property of electromagnetic waves.
When I looked up mass in wikipedia, they referred to the invariant mass of a system being calculated from the 'centre of momentum' frame of reference.
If you apply that to the entire universe, that frame of reference goes through the point of origin of the big bang. That point must still be the centre of momentum of the Universe, so that frame of reference must still be valid, and we all move relative to it. ( You can't move the centre of gravity of the Universe, without creating immense quantities of energy ).
So why can't we calculate where we are relative to the point of the big bang, and work out our motion relative to that? After all, it's the one 'real' frame of reference, whereas all others are arbitrary.

[colubridae]

Yes I appreciate twiglet and hackenslash clarifying it. My problem is accepting it, more than following the reasoning.

I’m not sure what you are expecting to achieve by asking your questions here. The others have given you interesting information. It isn’t their job or ability to give you understanding.

Hackenslash wrote that the speed of light is the only frame of reference that everything moves relative to.

Is that strictly true? I wouldn't call it a frame of reference. It's an unvarying property of electromagnetic waves.

I personally would concur with his statement. But it is a POV. If you don’t like it fine.
You seem to be mixing up different things.
Maxwells equations give a value for the speed of light.
Light travels at that speed. The frame of ref. hack spoke of is a frame moving at c.
I think.

When I looked up mass in wikipedia, they referred to the invariant mass of a system being calculated from the 'centre of momentum' frame of reference.

As I have said many times. You are now trying to reach a level of understanding that you can’t get from reading wiki articles or debating on a friendly atheist forum.

If you apply that to the entire universe, that frame of reference goes through the point of origin of the big bang. That point must still be the cenre of momentum of the Universe, so that frame of reference must still be valid, and we all move relative to it. ( You can't move the centre of gravity of the Universe, without creating immense quantities of energy ).

These remarks don’t match up. If you are able to understand complex concepts like ‘centre of momentum’, ‘moving universe CoG requiring immense energy’ you should be able to understand that the universe has no spatial centre.

So why can't we calculate where we are relative to the point of the big bang, and work out our motion relative to that? After all, it's the one 'real' frame of reference, whereas all others are arbitrary.

See above.
Also a frame of reference doesn’t mean a single spatial point.
My advice is to join a tutored course which will explain these things with greater understanding.

I’m interested in your background. Do you have a science degree?
Do you believe in god?

[Twiglet]

mistermack..

There's no need to resort to relativity explain that Kinetic Energy is a closed system looks the same, regardless of what speed the observer is moving at. That's what the mathematical proof I derived shows. An observer, travelling at speed Q, watches a ball being thrown. The extra energy "added" to the system by the act of throwing the ball is identical for any observer.

You could set about proving the same thing using relativistic equations, but it would be more complex.

As I understand it, your issue is that if you were moving at the same speed and direction as the ball, it would appear to you to have zero KE, right? And so from that, you've concluded that KE "depends on the observer" and is somehow arbitrary and not conserved.

The conservation of energy applies to a system: In this case, the ball and the person throwing it, or in hackenslashes case, the Earth and the person jumping up and down on it.

The observer must account for what happens to both the ball AND thrower, or the Earth AND jumper. The if Q=v, then the KE for the ball appears to be zero, however, the proof shows that required amount of energy is seen in *the person who throws the ball*, because of their recoil. You have to look at all components in the system.

Your question about the Big Bang is harder to answer, because we can't yet account for how all the mass is distributed, or how much there is, or how long ago the bang happened. There are some good guesses, but without concrete answers, it's impossible to progress. Also there are known problems with our sciences ability to describe the very early universe, where ideas of General relativity and Quantum physicsare required to describe what is happening, and the theories are incompatible at a fundamental level.

The questions about centre of mass/momentum of a system are really about ease of calculation more than anything else.

[colubridae]

Just by the by

If you apply that to the entire universe, that frame of reference goes through the point of origin of the big bang. That point must still be the cenre of momentum of the Universe, so that frame of reference must still be valid, and we all move relative to it. ( You can't move the centre of gravity of the Universe, without creating immense quantities of energy ).

Somewhere in the depths of my memory, I recall a german scientist (maybe E. Mach) who had a theory along the lines of ‘Inertia is an expression of the entire gravitational effect of the universe’ Bollocks of course.