Twins paradox and other special relativity topic discussion

[HydrogenBond]

Moderation note: The first 17 posts of this thread were moved from the Alternative theories thread “Come on, REAL Physics please!”, because they are a discussion of well-known theory, not the original threads alternative theory.

The twin paradox has to follow the laws of the conservation of energy. Only one twin was given energy relative to the other twin. Only one twin has the energy for real relativistic affects. Only the one with energy will show any real time dilation.

In other words relative velocity does not always express reality unless both references have the same energy. If we ignore the third equation of SR, which involved mass-energy, we can get results that can violate energy conservation to create special affects in math. The space-time affect in GR is also dependent on mass-energy, which is not reference dependent. The mass-energy is what creates the reference. The same is true of SR, with mass-energy or relativistic mass defining the real reference affects. I am not saying relative reference does not create the impression of this, but it may lack the energy to be real.

If we assume a relativity affect, that does not have the energy to back it up, we have created imaginary energy, which only exists conceptually. This gives us extra energy, conceptually, to create other imaginary things that will add up mathematically due to the original assumptions.

As an example, look at a train moving and a stationary observer. There are certain relative reference things that are useful. But if we do an energy balance based on reference, one reference sees the train moving and the other sees all the mountains in the background moving. If both are equal, I just created energy equal to the difference between mountains moving minus the train moving. Now I can use that energy to do other things. If I said, I only gave you enough energy to move the train, that tells us which reference is real and which is an illusion even if your eyes are being fooled. You can't trust your eyes and the assumption of relative reference. We have to assume we know the cut off between useful relative reference affects and that threshold where we begin to create extra energy. I am no expert but based on relative reference discussions it is not clear.

[Roadam]

Originally Posted by martillo

My new twins' problem is completely symmetrical and there's no way to decide which would age less or more.

Each of them would see the other age more, but in fact they would arrive home being the same age. Special relativity is overly simplistic becouse it doesnt take accelerations into account.

[martillo]

Each of them would see the other age more, but in fact they would arrive home being the same age.

"In fact"?
How would you prove that?
If you were one of the twins you wouldn't say this.

You have three frames of observations, two in each twin and in this case you as if you were in the proposed spaceship.

Now, is not the matter to pick the observation you feel more comfortable with. The problem is just that there are three frames of observations with contradictory (incompatible) observations! This is the inconsistency.

As I say in Section 1.1 - A:
"
A right theory cannot be inconsistent; the same phenomenon must have consistent predictions in different referentials of observation."

[Qfwfq]

Originally Posted by martillo

Well, if there are no waves and no particles what really exist?

Who says it must be an aut-aut?

Originally Posted by martillo

What do you propose?

While physicists have learnt to perform calculations on the outcome of experiments, the exact reality of what these "little thingies" are is something our minds weren't designed to comprehend. Like other animals, we evolved to survive. Like other apes, we evolved a great ability to manipulate our environment, hand in hand with an ability and drive to understand it.

Unlike other apes, we evolved an exaggerated ability, going far beyond the necessity to procure food, drink and protection for the purpose of survival; we can afford to be a mob of lazy clods that avoid physical effort, keep ourselves overly fed and comfy, even at the cost of squandering resources and ruining the environment, and along with this we also developed the ability and habit of asking questions like "What is the world, what's it made of, how does it work and how did it come to exist?". These are unnecessary for our survival, the answers are such that our minds aren't designed for and we can only edge nearer to understanding them, but never completely will.

Originally Posted by martillo

What are we doing here then?

We? We who? What's this, pluralis maestatis?

I talked about your approach to dicussion. Leaving isn't your only option, there's also that of polishing your conduct a bit.

[jerrygg38]

It seems as if everyone is leaving out half the equation

F = d (MV) /d(t) = M d(v)/d(t) + V d(m)/d(t)

The force equals the mass time the deriviative of the velocity with respect to time plus the velocity times the deriviative of the mass with respect to time.

What the equation shows is that a force applied to a mass increases its velocity and at the same time increases its mass.

[Pyrotex]

Originally Posted by jerrygg38

It seems as if everyone is leaving out half the equation

F = d (MV) /d(t) = M d(v)/d(t) + V d(m)/d(t)

The force equals the mass time the deriviative of the velocity with respect to time plus the velocity times the deriviative of the mass with respect to time.

What the equation shows is that a force applied to a mass increases its velocity and at the same time increases its mass.

Actually, no. You're reading the second half of the equation backwards.

It says the Force is equal to the rate at which the momentum changes.
And momentum equals (velocity * mass).

The momentum will increase as velocity increases over time.

The momentum will decrease as the mass of the system decreases over time.

Given a rocket that generates a force by burning propellent, there are two factors changing the momentum of the rocket: the velocity is increasing; and the mass (of the rocket) is decreasing, because the propellent is being expelled from the rocket. In fact, THIS is what generates the Force--Newton's second law: for every reaction (force that accellerates the rocket) there is an equal and opposite reaction (counter-force that pushes the exhaust in the opposite direction).

The force does NOT cause the mass to change. The mass is changing due to the nature of the object (a rocket which burns propellent)--and this affects the calculation of the magnitude of the force being generated.

[jerrygg38]

Originally Posted by Pyrotex

Actually, no. You're reading the second half of the equation backwards.



The force does NOT cause the mass to change. The mass is changing due to the nature of the object (a rocket which burns propellent)--and this affects the calculation of the magnitude of the force being generated.

JG: You rocket analysis is adding a further complication. In that case the total mass of the fuel decreases due to the expelled fuel. Simultaneously the velocity of the rocket and remaining fuel increases and the mass of the rocket and the remaining fuel increases.

The more simple equation is when an external force is applied to the system. Let us take an object and connect a rocket to it for awhile. This applies a force to the object. However the object does not lose any material. Thus the velocity of the object increases and the increased velocity is accompanied by an increase of mass of the object.

[Roadam]

Mass is not increased when you are coming close to the speed of light, its just harder to accelerate, thus you can imagine having more mass.

[jerrygg38]

Originally Posted by Roadam

Mass is not increased when you are coming close to the speed of light, its just harder to accelerate, thus you can imagine having more mass.

JG: Yes a point is reached where the input energy equals the output radiated energy so you hit a limit. You end up with a constant velocity near light speed and a photon energy field which you can keep increasing with great effort and high radiation. Of course you also want to bring the temperature down to near absolute zero. What a mess!

It is better to look at the sub light speed mass/velocity changes.

[CraigD]

Originally Posted by Roadam

Mass is not increased when you are coming close to the speed of light, its just harder to accelerate, thus you can imagine having more mass.

Originally Posted by jerrygg38

JG: Yes a point is reached where the input energy equals the output radiated energy so you hit a limit. You end up with a constant velocity near light speed and a photon energy field which you can keep increasing with great effort and high radiation.

To the best of my knowledge, these claims aren’t a prediction of relativity, nor are theysupported by any experimental data. Roadam and jerrygg, do you have any evidence suggesting otherwise?

Roadam’s claim,

Originally Posted by Roadam

Mass is not increased when you are coming close to the speed of light, its just harder to accelerate, thus you can imagine having more mass.

is practically and philosophically interesting, because it implies that a body “being harder to accelerate” – what is usually termed in physics a body’s “inertia” – can in some cases be independent of a body’s mass. This contradicts mechanics in the classical limit, which defines the force required to produce a give acceleration – “how hard it is to accelerate” – as directly proportional to a body’s mass , per the equation .

There are other definitions of mass. Two well know ones are the force of gravity stated in Newton's law of universal gravitation, given by , where is the gravitational constant, and are the mass of two bodies, and the distance between them, and mass–energy equivalence, given by , where is the energy resulting from the body’s annihilation, and the speed of light in vacuum.

There’s strong experimental support for the prediction that the mass of a body as defined by mass-energy equivalence increases relative to an observer as does it’s speed , as give by special relativity’s , where is the mass of the body as measured by an observer at rest relative to it. Such evidence comes from experiments in which charged particles – typically electrons – were accelerated to very high speeds (about .999996519 c) by devices such as the LEP in Geneva from 1989 to 2000, and collided with their antiparticle (positrons), and the total energy of their collision measured. Because the speed of the colliding particles and the total energy of their collision were precisely known, we can say with great confidence that special relativity’s prediction of their mass as defined by mass-energy equivalence is strongly confirmed.

That this also is true for a body’s mass as defined by universal gravitation (a question usually referred to as the equivalence of inertial and gravitational mass), while almost unanimously believe to be true by physicists, has to the best of my knowledge not be experimentally verified, or at least not to nearly the precision of special relativity vs. mass as defined by mass-energy equivalence and classical mechanics. Such a confirmation is technically difficult – which in modern experimental terms, equates to financially expensive – because the constant of gravitation is very small. In the case of the now-dismantled LEP, a detector of the difference in gravitational force due to the increase in mass of its accelerated leptons by a factor of about 379 would have to be extraordinarily sensitive. For example, a detector along the lines of the Cavendish experiment, using a 5 kg mass at a distance of 2 cm from the beam, would need a sensitivity of greater than . For comparison, the original Cavendish experiment, which has been improved upon only slightly in the past 2 centuries, had a sensitivity of about .

It’s worth noting, however, that a deep understanding of what mass actually is, in terms of the interaction of fundamental particles, is at the cutting edge of modern physics. Although the prediction of 20th century theory continue to be well confirmed by increasingly good experiments, the philosophical why underlying these predictions remain very much open questions.


JG’s claim,

Originally Posted by jerrygg38

Yes a point is reached where the input energy equals the output radiated energy so you hit a limit. You end up with a constant velocity near light speed and a photon energy field which you can keep increasing with great effort and high radiation.

Appears to me strongly contradicted by accepted theory and all experimental evidence. Nonzero mass particles are routinely accelerated to very high speeds and measured with very sensitive detectors, as described above, yet not observed to radiate except when interacting with particles. If beams such as the electron beam in the LEP were radiating in the way JG describes, they would be very bright, but are not observed to emit photons at all.