Welcome to
Science a GoGo's
Discussion Forums
Please keep your postings on-topic or they will be moved to a galaxy far, far away.
Your use of this forum indicates your agreement to our terms of use.
So that we remain spam-free, please note that all posts by new users are moderated.


The Forums
General Science Talk        Not-Quite-Science        Climate Change Discussion        Physics Forum        Science Fiction

Who's Online Now
0 members (), 141 guests, and 2 robots.
Key: Admin, Global Mod, Mod
Latest Posts
Top Posters(30 Days)
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
#54502 10/06/15 09:15 PM
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
I often say that talking of something approaching infinity is meaningless; but doesn’t the same apply to the speed of light?

Something that travels at c has an absolute speed. It remains the same irrespective of the speed of anything around it.

Something that travels at subluminal speed has no absolute speed, it's all relative.

Is the complication of changing from relative motion to absolute motion another reason why it is not possible to accelerate from one to the other?


There never was nothing.
.
Joined: Feb 2007
Posts: 1,840
R
Megastar
Offline
Megastar
R
Joined: Feb 2007
Posts: 1,840
Originally Posted By: Bill S.
I often say that talking of something approaching infinity is meaningless; but doesn’t the same apply to the speed of light?

Are you asking if 'the speed of light' is meaningless, or are you referring to something 'approaching the speed of light'?

Originally Posted By: Bill S.
Is the complication of changing from relative motion to absolute motion another reason why it is not possible to accelerate from one to the other?

Particles have mass due to interaction with the Higgs field, without which all particles would be massless and traveling at c
Special relativity explains why a massive particle is confined to subluminal velocity.
Correct me if I'm wrong at any point.


"Time is what prevents everything from happening at once" - John Wheeler
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
Originally Posted By: Rede
Are you asking if 'the speed of light' is meaningless


No, I was wondering if there was any meaning to talking as though there were some significance to a transition from relative motion to absolute motion.

I'm not sure I get the significance of the source of mass. So it would probably be off topic to comment on the oversimplification of attributing mass to interaction with the Higgs field.


There never was nothing.
Joined: Feb 2007
Posts: 1,840
R
Megastar
Offline
Megastar
R
Joined: Feb 2007
Posts: 1,840
Originally Posted By: Bill S.

I'm not sure I get the significance of the source of mass. So it would probably be off topic to comment on the oversimplification of attributing mass to interaction with the Higgs field.

I don't think it's off topic. I'd say it's central to the issue. What's more, I agree about the likelihood of oversimplification. It seems there may more to mass than the Higgs field interaction. However, I'm not about to make pronouncements on the strength of a few website articles. If you have anything authoritative, I'd be glad to hear of it.


"Time is what prevents everything from happening at once" - John Wheeler
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Hi Bill S not back I see much what I thought would happen has smile

However I saw this
Originally Posted By: Bill S.
Is the complication of changing from relative motion to absolute motion another reason why it is not possible to accelerate from one to the other?

You have all the building blocks with QFT to solve this and it's all about energy .. so lets do it.

Lets take a zero mass item like a photon you know it has energy and you once worked out it must have
GR stress energy. What you did not specifically do is work out from an energy perspective they are exactly
the same and opposite and cancel out to zero.

What we need is the concept of negative energy (https://en.wikipedia.org/wiki/Negative_energy)

Lets write the generic formula for any body to spacetime

E total = E kinetic - E gravity + E rest mass

So a zero rest mass object has zero total energy from our spacetime frame and always will smile

When a photon is born it instantly goes to the speed of light,and exists as a positive and negative energy.
Then lets say you absorb it via your skin sure you feel the positive energy as heat, but you didn't feel that
you also gained it's negative gravitational energy you just got a little heavier. Your net gain of energy to
spacetime was zero.

Just for kicks try a stationary black hole and you should see it has an energy of zero, the rest mass and the
gravitational energy cancel smile

If an object has an E rest value no amount of kinetic energy can remove it because as you make the object
move faster it's gravity energy increases so the first two terms always cancel out due to conservation of energy.

Now whats special in QFT is only a zero total mass object can move at the speed of light. Why well because rest
mass (E rest) is a "structure" or "resonance" in the field. The field has to communicate that "structure" with
the movement. The field communication speed is why objects really do shorten up in the direction of motion.

The complicated part is the first classical tendency is to have the "structure" communicate it's movement
forward to the field but that is classical physics thinking again. You have a resonance in the field and that
resonance is everywhere in the field and there is a non zero probability that it will appear in any point in the
universe. Fortunately we most often see the most likely answer which agrees with our classical physics motion.
Entanglement and quantum tunneling are manifestations of the true nature of the movement when that classical
physics breaks down.

So in this simple layman scheme we have zero mass objects as waves in the field and things with rest mass
as more complicated resonances that have to be transmitted.

It's a bit of a simplification for clarity but if you really want to follow it Matt Strassler has the details on
"class 0" and "class 1" waves which is there technical names.

http://profmattstrassler.com/articles-an...tion-of-motion/

So the short answer is class 1 waves can't move at speed of light and only class 1 waves can describe rest mass.
http://profmattstrassler.com/articles-an...les-are-quanta/

Originally Posted By: Matt Strassler
And so we conclude: The particles of nature are quanta of relativistic quantum fields. The massless ones are quanta of waves in fields that satisfy a Class 0 equation. The ones with mass correspond to fields with a Class 1 equation. There are many more details to investigate. But this fact is among the most fundamental properties of our world.

See your gut feel that there had to be a solid difference was justified and it is wave type we don't discuss
this stuff on layman forums but you are well beyond that now.

Go any deeper Bill S and you get an honorary degree smile

Last edited by Orac; 10/08/15 07:00 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Bill S if you are intending to go deeper you will need to follow the negative side of energy (you pretty much ignored or don't believe it so far). You need to start here and you may want to think about Matt's last comment

http://profmattstrassler.com/articles-an...ermions-differ/

Last edited by Orac; 10/09/15 02:29 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
Thanks Orac. Quite a lot to think about there, and very little time to do it. I've not said much about negative energy because I don't know much about it. No basic objection to it, though.


There never was nothing.
Joined: Dec 2010
Posts: 1,858
B
Megastar
Offline
Megastar
B
Joined: Dec 2010
Posts: 1,858
Orac has had a lot to say about this subject, but I thought you might be interested in this article by Ethan Siegel. I don't think it really answers your question, but it is certainly related to it.

Ask Ethan #109: How Do Photons Experience Time?

Bill Gill


C is not the speed of light in a vacuum.
C is the universal speed limit.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Originally Posted By: Bill
Orac has had a lot to say about this subject, but I thought you might be interested in this article by Ethan Siegel. I don't think it really answers your question, but it is certainly related to it.

Nothing wrong with that science mag fluff story but it does leave a few things unclear aside from Bill'S original question.

(i) Why does length contract with motion?
(ii) Why does time contract with motion?

I am guessing Bill S is going to want those answers as well. From his current understanding there is a good chance he
might put it together depends how he goes with class 0 and class 1 waves.

As stated the correct answer is mass is a class 1 wave and class 1 waves can't travel at the speed of light.
That is just an answer a layman will never understand they don't see matter as waves thanks to classical physics.

I am guessing he is going to turn our class waves into spin shortly if Bill S is true to form.

Lets see where Bill G is at, do you accept the science that matter and mass are just waves or spins?
Ask a layman and they will say no, ratio is 90% or higher last I looked. They can feel the world is solid .. true story.

I am with the other scientists in the minority and yet we don't care smile

Hint for Bill S: 1982 Nobel prize winner Kenneth G. Wilson in case you need it.

Last edited by Orac; 10/10/15 06:08 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
Interesting link, Bill. I was a little surprised that Ethan came down firmly on the "photons don't experience time" side without mentioning the other side of the argument.


There never was nothing.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
I’m struggling a bit with the class 0 and class 1 waves, probably because of the maths.

So far I think I have gathered that there are class 0 and class 1 fields, and class 0 and 1 waves are waves in those fields.

Class 0 waves can have any frequency, but always travel with equal speed, which is c.

Class 1 waves have a minimum frequency, and can travel at a range of speeds, < c.

Particles that are excitations of class 0 fields are massless bosons.

Particles that are excitations of class 1 fields are all fermions, and therefore are massive.

Tentative conclusion: All the matter and energy in the Universe amount, essentially, to excitations in a variety of fields.

Relevance to OP: Massive objects cannot be accelerated to c because they and massless objects are excitations in incompatible fields.


There never was nothing.
Joined: Dec 2010
Posts: 1,858
B
Megastar
Offline
Megastar
B
Joined: Dec 2010
Posts: 1,858
Well, keep in mind that some people used to think that neutrinos were massless. It wasn't for sure, there really wasn't any real evidence either way. Then they figured out that they were oscillating between types. In order for them to be able to oscillate they must be experiencing time. Therefore they must be traveling at less than C. Therefore they must have mass. So the idea that massless particles don't experience time is not at all new.

Bill Gill


C is not the speed of light in a vacuum.
C is the universal speed limit.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Originally Posted By: Bill S.
I’m struggling a bit with the class 0 and class 1 waves, probably because of the maths.

Okay I am going to cheat an give you a real world example that might help you visualize the situation without the maths.

Wind could be seen as a class 0 wave in air, a tornado or hurricane could be viewed as a class 1 wave in air.

The later can not move as fast as the air itself because on the parallel sides you have + and - speed relative to its motion.
Here I once drew this for Marosz and it sort of works

Those side movements are problematic and that is symptomatic of class 1 waves.
Class 1 waves always contain internal motion which are relative to the actual motion that is what makes them class 1.

You can see if that was a class 1 wave moving at the speed of light the top side would have to move faster than light or it couldn't rotate.

There you go no maths but a simple visual example.

It should also be apparent most class 1 waves will rotate in some way because otherwise they may be viewed
as a unrelated wave front. So we are slowly introducing the concept of spin.

Originally Posted By: Bill S.
Tentative conclusion: All the matter and energy in the Universe amount, essentially, to excitations in a variety of fields.

Correct and now you have a hypothesis to test smile

Try working out why matter contracts now !

Originally Posted By: Bill S.
Relevance to OP: Massive objects cannot be accelerated to c because they and massless objects are excitations in incompatible fields.

I will correct they can't go at the speed of light because some part of the internal motion would be required to go faster than light.

You would have the same problem trying to make a tornado move at the same speed as it's spin ... NOT POSSIBLE.

Last edited by Orac; 10/12/15 04:51 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
The tornado analogy is great (no maths - woot), but tornadoes always spin in the plane of travel. Would this also apply to particles. If not, the particle spin speed would not add to the travel speed if the two were at right-angles.


There never was nothing.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Originally Posted By: Bill S.
The tornado analogy is great (no maths - woot), but tornadoes always spin in the plane of travel. Would this also apply to particles. If not, the particle spin speed would not add to the travel speed if the two were at right-angles.

If the waves didn't stay in the general vicinity of a single point would you call them particles smile

Going back to meteorology example there is no difference between a high or low pressure cell, a hurricane and a tornado.
What is different is the size and energy of the wave relative to the human perspective. Saying something isn't spinning
with the plane of travel can be very tricky look at space orbits as another example.

Particles will tend to go for volumes of spin not planes think about the uncertainty principle.

What becomes important in defining a particle or a tornado is the human perspective. That is why the mathematics of
class 1 is so hard it describes things on vastly different scales and there isn't a definitive cutoff that this is a particle
and this isn't, deciding when something is a tornado can be equally tricky. I imagine like physicists there is some sort
of rules a meteorologist uses.

What we end up doing is defining both relative to how we generally encounter them in our normal enviroment.

All that ends up with particles being quantum waves holding proximity to a point, which we then call Quantum spin.

You need to however have in the back of your mind the definition of a particle isn't a hard science definition smile

Finally we need to deal with the fact when we are at the speed of light spin itself takes on a weird form and look
because of relativity which Paul Dirac solved in 1928 when he converted the class 1 classical equations in relativistic
ones (https://en.wikipedia.org/wiki/Relativistic_wave_equations)

Here is the usual visualization


After a 360 degree rotation, the spiral flips between clockwise and counterclockwise orientations.
It returns to its original configuration after spinning a full 720 degrees. So one rotation is only half a spin of the fields.

Notice none of the fields cross themselves or any other field.

If you are really observant you will also notice there are two spins as drawn one of the classical orbital
angular momentum kind of the box itself in the middle and one of the fields which can only be described easily by
equations. The situation is correct in Quantum mechanics both spins can be present.

Last edited by Orac; 10/13/15 09:08 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Sorry I should have put this if you map just the angular momentum wave in the field it looks like this



You should be able to reconcile the two image if you watch the field movements carefully in the upper image.


I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
I've just had a quick look through your posts, and if they deal with the point:

"If not, the particle spin speed would not add to the travel speed if the two were at right-angles."

I may need some simplification.


There never was nothing.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
What we have is the concept of quantum spin being the movement of energy in the field itself NOT the classical particle
mass rotating energy. That classical particle rotation can exist in some situations in addition to the quantum spin.

The key point is that the field can only move at the speed of light that is what sets the velocity for class 0 waves. The fact
we can measure the energy in the field as classical angular momentum tells us the energy is behaving like a classical field.

In some sense there is no more important detail in physics because here we have this quantum world suddenly exhibiting a
very classical behaviour in that once you start energy in the field rotating it exhibits classical momentum. There are very
few Quantum and Classical physics connections and yet here we have one.

The only requirement we made for that was that energy can not be transferred in the Quantum field faster than c.

A spin 1 particle has relative field motions at right angles to the direction of motion and will not be able to move at the
speed of light with the above restriction, same problem as a tornado moving at its spin speed.

There is actually a much more profound effect that will be obvious as a spin 1 moves faster given that restriction.

Think about it smile


I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Joined: Aug 2010
Posts: 3,570
B
Bill S. Offline OP
Megastar
OP Offline
Megastar
B
Joined: Aug 2010
Posts: 3,570
Originally Posted By: Orac
What we have is the concept of quantum spin being the movement of energy in the field itself NOT the classical particle mass rotating energy. That classical particle rotation can exist in some situations in addition to the quantum spin.


Are we talking about a particle having classical spin and quantum spin? Would both impart angular momentum to the particle?

Quote:
The key point is that the field can only move at the speed of light that is what sets the velocity for class 0 waves. The fact we can measure the energy in the field as classical angular momentum tells us the energy is behaving like a classical field.


I’m never quite clear about field movement. Should it be seen as the field moving, or something (energy/information/ripples?) moving in the field. If a field already fills space, in what sense does it move?

If a particle can be considered as a particle or a wave, and the particle has angular momentum, can the angular momentum be measures when the observation “shows” a wave? If not, what happens to the angular momentum?

Quote:
In some sense there is no more important detail in physics because here we have this quantum world suddenly exhibiting a very classical behaviour in that once you start energy in the field rotating it exhibits classical momentum. There are very few Quantum and Classical physics connections and yet here we have one.


Is there a form of rotation that could be considered a quantum momentum, as distinct from classical momentum?

Quote:
A spin 1 particle has relative field motions at right angles to the direction of motion and will not be able to move at the speed of light with the above restriction, same problem as a tornado moving at its spin speed.


This is spin 1, rather than class 1 particles?

Quote:
There is actually a much more profound effect that will be obvious as a spin 1 moves faster given that restriction.


Clues?


There never was nothing.
Joined: May 2011
Posts: 2,819
O
Megastar
Offline
Megastar
O
Joined: May 2011
Posts: 2,819
Originally Posted By: Bill S.
Are we talking about a particle having classical spin and quantum spin? Would both impart angular momentum to the particle?

Both can exist in a particle together and yes both impart angular momentum as the quantum wave is classical in that respect.
They can even counter rotate like Contra-rotating propellers. They share no points that there motions clash just like the propellers.

In a sense on a macro scale you do that when you spin a solid object the quantum spins are still doing there own thing.
Normally the quantum spins in a solid would be pretty much uniformly random so you would never notice.

When the question was asked in Scientific America only one of the three physicists they used actually got it right smile
http://www.scientificamerican.com/article/what-exactly-is-the-spin/

Originally Posted By: Bill S.
I’m never quite clear about field movement. Should it be seen as the field moving, or something (energy/information/ripples?) moving in the field. If a field already fills space, in what sense does it move?

You wouldn't know there was a field unless you could see the energy exchange (think of Higss pre discovery).
So a field is moving in the sense you can measure an energy exchange remind you of something ... Relativity?

So if you prefer turn field movements to relative field movements because that is all we can say.

Quote:
Is there a form of rotation that could be considered a quantum momentum, as distinct from classical momentum?

I am going to say no for a historical problematic reason and save myself a headache smile

If you treat it strictly in that manner you end up at De Broglie–Bohm theory and the waves are called pilot-waves.
That theory comes to a crashing end, although some still try to keep it alive, but it's like flat earth theory.

Quote:
This is spin 1, rather than class 1 particles?

Now you even pick up my errors so you definitely have got it ... yes class 1 sorry.

Originally Posted By: Bill S.
Clues?

Lets say things are going to get shorter in the direction of movement of class 1 waves smile

Last edited by Orac; 10/16/15 06:44 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.
Page 1 of 2 1 2

Link Copied to Clipboard
Newest Members
debbieevans, bkhj, jackk, Johnmattison, RacerGT
865 Registered Users
Sponsor

Science a GoGo's Home Page | Terms of Use | Privacy Policy | Contact UsokÂþ»­¾W
Features | News | Books | Physics | Space | Climate Change | Health | Technology | Natural World

Copyright © 1998 - 2016 Science a GoGo and its licensors. All rights reserved.

Powered by UBB.threads™ PHP Forum Software 7.7.5