How long does it take for a single photon to travel from the sun?

[renormalised (Carl)]

Originally Posted by sjastro

This is not true with SR. If one plots the Lorentz factor 1/sqrt(1-(v2/c2)) against velocity v, an asymptote is found at the line v=c. In this case an infinite Lorentz factor tells us that particle velocity cannot reach or exceed the speed of light c.

Regards

Steven
http://users.westconnect.com.au/~sjastro/small

True, but here in lies the problem. The reason why a particle (except for the photon) cannot reach the speed of light is because of the infinities which crop up. This is why I've been arguing that SR (and even GR, in some respects) is not self consistent and has problems. However, and it may come as a surprise to some, SR doesn't preclude particles traveling faster than the speed of light. People misunderstand what Einstein said, and many scientist misquote him. He originally said that no material object can travel at the speed of light. There are solutions for particles in SR to travel faster than light, but never as slow as light speed. Same problems happen for them when approaching c as occur for those particles which travel slower than c. You'll know them as tachyons. Now, they haven't detected them, but then again there's a lot of things even stranger than tachyons which physicists have said exist but have never detected. Super symmetric particles and the Higgs Boson, for example.

The reason why the fudge factors are looked at in the light that they are is because they take what should be reworked theories and make them palatable by hiding the mistakes made which create the infinities in the first place. Sure, they look good and work well, however they leave a nagging feeling that maybe you should try and get things right in the first place. So far as the cosmological constant is concerned, the jury is still far from giving a verdict on this. It's all been predicated on the observations of about half a dozen distant supernovae, far from being a statistically significant sample. But it's a start. If it works out, great, but then I think we should leave it for awhile until we can say definitively whether it's a fact of life or not. In so far as 1/2 spin numbers goes, it's one area where SR and quantum mechanics have come together rather well. But that is only one application where it actually works. It doesn't mean, then, that it'll work in every other case it's applied. Also, it wasn't so much as a fudge factor than it was a solution which appeared ad hoc, but in actual fact elegantly and self consistently predicted and observationally proved a characteristic of elementary particles. It's not often something like that happens.

[sjastro]

Originally Posted by renormalised

True, but here in lies the problem. The reason why a particle (except for the photon) cannot reach the speed of light is because of the infinities which crop up. This is why I've been arguing that SR (and even GR, in some respects) is not self consistent and has problems. However, and it may come as a surprise to some, SR doesn't preclude particles traveling faster than the speed of light.

This is the very point I am making. The role of infinity in SR has a definable physical interpretation. It doesn't in anyway compromise the theory.

Particles traveling faster than light (tachyons) need to be looked at in the full context. They are solutions to a symmetrical version of SR. Tachyons cannot travel below the speed of light for the same reasons as "normal" particles cannot travel faster than light. In both cases the speed of light is still a barrier.

[renormalised (Carl)]

Originally Posted by sjastro

....Particles traveling faster than light (tachyons) need to be looked at in the full context. They are solutions to a symmetrical version of SR. Tachyons cannot travel below the speed of light for the same reasons as "normal" particles cannot travel faster than light. In both cases the speed of light is still a barrier.

That's what I said

But most people wouldn't know this, and so they keep to the popular interpretation.

This is the very point I am making. The role of infinity in SR has a definable physical interpretation. It doesn't in anyway compromise the theory.

Yes, and I agree that infinities in SR have a definable interpretation, in that they are the reason for the speed of light barrier. However that doesn't lessen the fact that they're a cause of problems for SR. What needs to be done is more theoretical research into the actual nature of photons and what exactly happens when particles travel at lightspeed.... not just the usual interpretation of "Oh yeah, they reach infinite mass and zero size....SR said so". That makes them singularities (of infinite mass). Wouldn't matter from what inertial frame of reference you observed at, it would be disastrous for both you and the particle (or person in the ship).

[maksutover]

Great discussion people.

I just want to add that Einstein used Reimannian mathematics for most of his work in GR and simply followed the work of Hertz and Plank to "discover" (and i use that term losely) the photoelectric effect which he won the nobel prize for.
Please dont get me wrong, im not belittling the poor guy, in fact i think his contributions were immense, but in no way was he a one man show and as renorm put it, the beginning and end of physics.

[sjastro]

Originally Posted by renormalised

Yes, and I agree that infinities in SR have a definable interpretation, in that they are the reason for the speed of light barrier. However that doesn't lessen the fact that they're a cause of problems for SR. What needs to be done is more theoretical research into the actual nature of photons and what exactly happens when particles travel at lightspeed.... not just the usual interpretation of "Oh yeah, they reach infinite mass and zero size....SR said so". That makes them singularities (of infinite mass). Wouldn't matter from what inertial frame of reference you observed at, it would be disastrous for both you and the particle (or person in the ship).

The building of progressively more powerful particle accelerators such as the Large Hadron Collider is more than ample proof of the futility of accelerating particles to the speed of light. It's no coincidence that protons will be accelerated to "only" 99.99% the speed of light using enormous amount of potential energy.

Since m and E are related (E=mc2) most of the increase in mass of a particle approaching the speed of light is in fact taken up by the KE of the particle. If it was possible for the particle to reach the speed the light, the KE would become infinite. The mass won't turn into gravitational sink.

Regards

Steven

[renormalised (Carl)]

Originally Posted by maksutover

Great discussion people.

I just want to add that Einstein used Reimannian mathematics for most of his work in GR and simply followed the work of Hertz and Plank to "discover" (and i use that term losely) the photoelectric effect which he won the nobel prize for.
Please dont get me wrong, im not belittling the poor guy, in fact i think his contributions were immense, but in no way was he a one man show and as renorm put it, the beginning and end of physics.

Glad you're enjoying it

You know, maybe we should be making Einstein walk the "Planck", until it "Hertz"

Well, at least that's what I'm trying to do

[renormalised (Carl)]

Originally Posted by sjastro

The building of progressively more powerful particle accelerators such as the Large Hadron Collider is more than ample proof of the futility of accelerating particles to the speed of light. It's no coincidence that protons will be accelerated to "only" 99.99% the speed of light using enormous amount of potential energy.

Since m and E are related (E=mc2) most of the increase in mass of a particle approaching the speed of light is in fact taken up by the KE of the particle. If it was possible for the particle to reach the speed the light, the KE would become infinite. The mass won't turn into gravitational sink.

Regards

Steven

That's true....doesn't matter what they do, they just don't have enough energy to accelerate them to lightspeed. It takes infinite energy.... and there it is again. An infinity....it can't be avoided. That's why SR becomes nonsensical. There wouldn't be enough energy in all the dimensions and parallel universes to accelerate a particle to lightspeed.

About mass and KE.....it could either go two ways. One, the KE becomes infinite, which can't happen....or two, since M and E are equivalent, the mass becomes infinite and you get an infinitely heavy singularity. Either way, the gravity must become infinite. If that particle were to stop (by hitting something, say), the energy has to go somewhere. Since it's infinite, it doesn't matter whether it's transfered to the body it hits or to itself, it becomes mass....an infinite mass derived now from PE. Wam.....instant infinitely heavy black hole. Goodbye universe

[skwinty (Steve)]

Originally Posted by renormalised

Glad you're enjoying it

You know, maybe we should be making Einstein walk the "Planck", until it "Hertz"

Well, at least that's what I'm trying to do

What I don't understand about this attitude is:

1. There are no other testable theories at present.
2. No-one implied that Einstein was the be all and end all of anything.
3. The implication being made now is that Einstein was a copy cat who only progessed the work of others.
4 While you are stating facts about the renormalisation of mathematical equations to get rid of infinities, the fact remains that infinities exist and surely should be reflected in any theory or in any equation.
5. You make no distinction between singularities in space and singularities in time.
6. Perhaps we remove the tan function from our calculators as it too produces infinities.

Apart from all this, who is to say what occurs in a black hole or singularity as the mass approaches infinity and the volume approaches zero. Perhaps this is the gateway to the multiverse and this gateway closes after a critical point is reached. ie the blackhole dissappears.

Until such time as the new theories progress into something tangible, you shouldn't toss the baby out with the bath water.

[Karls48 (Karl)]

Some couple hundred years ago French Academy of Science has declared that object heavier then air cannot fly. No doubt that, to come to this conclusion they considered all the laws of physic known at that time. If everyone believed to those learned scientists we would not have airplanes today. If we believe that faster then light speed is impossible, then it will be impossible. We never learn from the past.
Use million of horses to pull object to break speed of sound barrier. No hope. Take different approach to it and you will achieve it with power of few thousand of horsepower.

[renormalised (Carl)]

Originally Posted by skwinty

What I don't understand about this attitude is:

1. There are no other testable theories at present.
2. No-one implied that Einstein was the be all and end all of anything.
3. The implication being made now is that Einstein was a copy cat who only progessed the work of others.
4 While you are stating facts about the renormalisation of mathematical equations to get rid of infinities, the fact remains that infinities exist and surely should be reflected in any theory or in any equation.
5. You make no distinction between singularities in space and singularities in time.
6. Perhaps we remove the tan function from our calculators as it too produces infinities.

Apart from all this, who is to say what occurs in a black hole or singularity as the mass approaches infinity and the volume approaches zero. Perhaps this is the gateway to the multiverse and this gateway closes after a critical point is reached. ie the blackhole dissappears.

Until such time as the new theories progress into something tangible, you shouldn't toss the baby out with the bath water.

It's not an attitude, Steve. Everyone has followed Einstein like he's some sort of God (and don't say that people don't, they do) of physics. He's not. It's like all scientist, they come up with an idea that seems to be infallible and they treat them like they can do no wrong. They did the same to Newton and they've done the same to Hawking, but now quite a few scientist have questioned Hawking's premises. He's even gone back on a few of his ideas himself!!!!. But now he's looking at other ways to prove himself right. It's all ego and hubris.

All scientist work on the assumptions of others and try to progress science by extending those assumptions. Sometimes, they come up with some of their own. In any case, that wasn't my point.

Yes, the infinities do exist, but only as mathematical constructs. No physical observation or experiment ever carried out has proved the existence of an infinity. Why??, because an infinity by its very nature is an incalculable sum, hence it's nonsensical. That's the reason why renormalisation is used. To negate the infinities.

It doesn't matter whether it's a singularity in space or time. Because space and time are coupled, there can be no distinction between either. They both look the same.....in fact they are the same, given what we know of either.

All mathematical functions will produce infinities if you take the maths to its limits....it doesn't mean that the maths is wrong altogether, it just has serious problems when it reaches certain conditions (like SR and other theories do), and should be revised and/or discarded when it no longer works, for those conditions. It may work fabulously up until that point.

I'm not tossing any baby out with the bath water....all I'm saying is that the water has gone cold and should be changed, the baby stays in the bath

At least until Mother decides to take him/her out

[sjastro]

Originally Posted by renormalised

About mass and KE.....it could either go two ways. One, the KE becomes infinite, which can't happen....or two, since M and E are equivalent, the mass becomes infinite and you get an infinitely heavy singularity. Either way, the gravity must become infinite. If that particle were to stop (by hitting something, say), the energy has to go somewhere. Since it's infinite, it doesn't matter whether it's transfered to the body it hits or to itself, it becomes mass....an infinite mass derived now from PE. Wam.....instant infinitely heavy black hole. Goodbye universe

No it doesn't. Relativistic mass = Rest mass + KE. Rest mass is constant. KE is tied up in the velocity of the particle. There will be no increase in the "mass component" of relativistic mass.

If you are so against infinities why do you readily accept infinite mass in your argument.

Regards

Steven

[sjastro]

Originally Posted by skwinty

6. Perhaps we remove the tan function from our calculators as it too produces infinities.

[AGarvin]

No it doesn't. Relativistic mass = Rest mass + KE. Rest mass is constant. KE is tied up in the velocity of the particle. There will be no increase in the "mass component" of relativistic mass.

Yes. The full equation is:

E2 = p2c2 + m2c4

where m = rest mass and p = momentum. The shortened version of the equation is just to illustrate the relationship between mass and energy.

[skwinty (Steve)]

Originally Posted by renormalised

It doesn't matter whether it's a singularity in space or time. Because space and time are coupled, there can be no distinction between either. They both look the same.....in fact they are the same, given what we know of either.

If this is indeed correct, then there is no difference between the singularity described in the big bang and the singularity or black hole in the middle of our galaxy or omega centauri.
My understanding is that there is a subtle distinction between space and time singularities

[renormalised (Carl)]

Originally Posted by sjastro

No it doesn't. Relativistic mass = Rest mass + KE. Rest mass is constant. KE is tied up in the velocity of the particle. There will be no increase in the "mass component" of relativistic mass.

If you are so against infinities why do you readily accept infinite mass in your argument.

Regards

Steven

I didn't accept infinite mass in my argument except as a postulate of SR. When I mention an infinite mass or energy, it's in relation to SR postulates.

If rest mass is constant (invariant), and it's only the relativistic mass which becomes infinite, then any mass increase is nothing more than "relative" and therefore is a perspective illusion based on one's PoV. It's an apparent mass based on the addition of energy of motion (KE), not the real or proper mass of the system. It means that whilst it has measurable physical effects and can be confirmed by experiment, it's still nothing less than an illusion and that we don't really understand what we're looking at.

[maksutover]

STEVE! Dude take it easy! No matter what anyone says, it only their opinion! You seem to be very defensive in regards to this topic.
I totally agree that Einstein was a genius! But what renorm (i think) and I are stressing is that he is slightly over exemplified in physics (for God knows what reason). If you study the biography of people like Sir Issac, you'll see that he became the greatest mathematician in the world in about 18 months from scratch!

Also I recommend reading "The Infinite Book" by John Barrow. As impossible, nonsensical and outrageous as infinity might be, the basic principles of calculus and other mathematical branches will cease to exist without it.

So my children, learn to embrace it

[AGarvin]

If rest mass is constant (invariant), and it's only the relativistic mass which becomes infinite, then any mass increase is nothing more than "relative" and therefore is an illusion based on one's PoV. It's an apparent mass based on the addition of energy of motion (KE), not the real or factual mass of the system.

Yes, that's why it's called relativity. Regardless of what you observe my (relativistic) mass as, in my reference frame my mass doesn't change. I'm not actually gaining more atoms. The total energy of the system increases with momentum relative to the observer.

It means that whilst it has measurable physical effects and can be confirmed by experiment, it's still nothing less than an illusion and that we don't really understand the true characteristics of spacetime.

It sounds like your trying to equate spacetime with something physically real (????). Spacetime is not a real thing, it's just a construct that in the mathematical framework or relativity theory has 3 spacial dimensions and one temporal. M-Theory has it's own version of spacetime that has 10 spacial and one temporal.

Also, the concept of spacetime is not Einsteins, it was developed by Hermann Minkowski 3 years after Einsteins paper in 1905 and it was Minkowski who took SR and first placed it in a geometric framework - spacetime.

[renormalised (Carl)]

Originally Posted by AGarvin

Yes, that's why it's called relativity. Regardless of what you observe my (relativistic) mass as, in my reference frame my mass doesn't change. I'm not actually gaining more atoms. The total energy of the system increases with momentum relative to the observer.



It sounds like your trying to equate spacetime with something physically real (????). Spacetime is not a real thing, it's just a construct that in the mathematical framework or relativity theory has 3 spacial dimensions and one temporal. M-Theory has it's own version of spacetime that has 10 spacial and one temporal.

Also, the concept of spacetime is not Einsteins, it was developed by Hermann Minkowski 3 years after Einsteins paper in 1905 and it was Minkowski who took SR and first placed it in a geometric framework - spacetime.

And I agree with everything you have said here, so we have no differences. Einstein never even came up with relativity in the first place. Galileo was the first to theorise about relativity. Einstein's theories just built on that earlier work (along with Newton's work as well, of course).

But that still doesn't change what I have written. I'm trying to get people to look at different theories (in this case SR, etc) in a critical manner and not just take what's said at face value. I'm not saying that SR should be turfed out in the garbage....upto a point it works brilliantly, but it has problems with strong gravitational situations, accelerated motions (the reason why AE formulated GR) and with infinities in the equations. Heck, quantum physics has enough problems of its own with infinities and other oddities, but it still works in most situations. We just need to be more critical with the answers we come up with, the theories we formulate and how we overly place great scientists on impossibly high pedestals.

I'll bet, in 50 or 100 years time, someone is going to find our conversations here rather quaint. They'll probably laugh at our ignorance and end up filing our posts on their holocrystal storage device, just before they board Flight 251 for the Interdimensional Mechanics conference at the Hawking Institute on Rigel 8

[skwinty (Steve)]

Originally Posted by maksutover

STEVE! Dude take it easy! No matter what anyone says, it only their opinion! You seem to be very defensive in regards to this topic.

Hi Maksutover
Not getting defensive, just expressing my opinion wrt to the comments that are being made in this discussion.
I call it robust debate.

[skwinty (Steve)]

The outstanding problem requiring resolution wrt to relativity is how to unite gravity with the WNF,SNF and EMF.
In the beginning of the universe, the universe was massive(Einstein's theory of gravity) and smaller than an atom(Quantum Theory).
Herein lies the problem as these two theories do not overlap or concur.

String Theory resolves these issues by saying that the "string" is the indivisible building block of the universe and the "unification" of gravity, WNF,SNF and EMF are contained within the "vibration" of the "string".

This leads to the Quantum Theory of Gravity. Einsteins Theory can predict the future with 100% certainty(ie the planet is here today and there tomorrow) whilst Quantum Theory only predicts possible futures or probabilities.

So the holy grail is to combine certaintities with uncertaintities.
Now, gravity pops ups in the string theory by virtue of the math and initial assumptions and it is not neccesarily Einsteins version of gravity.

Now, one dimensional strings are not the only strings that occur.
Single dimensional strings are called branes and multidimensional strings are called p-branes where p denotes the number of dimensions.

These branes exist in a multidimensional space time.
The implication of this is, our universe may not be the only universe around.

Now, if there are more then the possibility exists that these universes will collide with each other. This may well explain the big bang, singularities,black holes and infinite mass in zero volume. These conditions are not permanent and may well exist only for a "short period".

Well, thats my 2 cents worth.