Bart

Did you read the link? Like Capt'n said, time dilation has to do with relative speed. A muon has, on average, a certain lifetime before it decays into other particles.

 

Muons in relative motion have a longer lifetime on average than muons at rest. Why? Because they are moving. Time runs slower for the moving muons, as compared to time at rest.

 

At CERN, muons traveling at 99.7 percent the speed of lights showed a 12X increase in their lifetime. This as measured by laboratory clocks (laboratory reference frame). The muons last longer because they were moving at 99.7 % c . And Einstein's time dilation formula says this speed produces a slowing of the muon time of 12x. REF: C. M. Will, Was Einstein Right? Putting General Relativity to the Test, p. 255.

Well, yes. But whether can not appear here also some other, unknown to us reason which so much improves the health of muons during their movement? If in earth's atmosphere, muons are created at an altitude of 60km and reaches 99.98% the speed of light, according to the theory of SR, the average of its lifetime of 2.2 microseconds, should extend to 50 times. Thus, the path length of muons could reach at most 33 km (2.2 x50x300 = 33,000 m). How, therefore, they achieve the level of the oceans and in such big amounts?

At CERN the particles are accelerated to a speed exceeding 99.995% of light, therefore, whether the lifetime of particles should extend at least 120 times?

If that happens one of two assumptions must be abandoned:

Causality -- Effects happen after causes.

The principle of relativity -- There is no preferred reference frame.

 

The problems with the former are probably self-apparent, but there are also issues with the latter. Instead of a nice unified theory, we'd have a hodgepodge of different mathematical relationships that just happen to be lorentz invariant.

Is very quick receiving information about a distant event, not an effect after the cause?

If I understand correctly, with this causality is perhaps now not everything so clear. Light signals reaching us from distant galaxies, show us their state before the billions of years from now. At the moment many of these very distant galaxies may well no longer exist.

OK, we are assuming that bats evolve enough intelligence to grasp the concept of relativity.

 

And, just like us, they will eventually build devices to send and detect photons at wavelengths invisible to their sight (radio, gamma, etc). And remember that, for most of history, humans could not "see" light traveling. It was always considered to be instantaneous. We had to use equipment to realize that light traveled at a certain speed.

 

Once chiropteran scientists can also build this equipment, they will quickly surmise that all radiation travels at c.

 

Their theory of relativity will be no different.

I wonder if we are not such symbolic Batmans who use light waves instead of sound waves?

What will be with SR theory if, at some future, it appears that there is unknown to us (like a light for bats), ultra-fast medium UFM, in which information signals may be transmitted to a million or more times faster than light, and this medium is already commonly used by more advanced civilizations in the cosmos.?

Sure it does. This is demonstrated in particle accelerators all the time. The faster the particles move, the longer they live on average. This is because of time dilation -- time for the particles rus slower than time for the laboratory. So from out point-of-view in the laboratory reference frame, the particles live longer than the same particles at rest.

 

Fro example, see link: http://www.physlink....perts/ae611.cfm

How does the longer distance traveled by a particle with a specific kinetic energy, is to be evidence of time dilation?

If one egg fall out from the table with a horizontal speed v, and the other egg with speed 2v, the time of life for both eggs before they are broken down, will be the same, despite the fact that the second egg will receive 2 times longer distance.

Here's a program that calculates DM:

 

http://users.telenet...om/program2.htm

 

When scientists observed a galaxy rotate and then added up an approximation of the mass of the visible matter they were surprised. According to general relativity, the galaxy should have spun itself apart. The galaxy would need an additional 5 times the observed mass for it to match the observations. This has since been proved with the WMAP:

 

http://map.gsfc.nasa.gov/

 

So, the mass of the universe is 4.6% baryonic matter, 23.3% non-baryonic (dark) matter and 72.1% dark energy. However, the matter in the universe is one sixth baryonic and five sixths dark matter.

 

In the '90's, two ideas competed for the dark matter crown. Weakly Interactive Massive ParticleS (WIMPS) and MAssive Compact Halo ObjectS (MACHOS). It seems that WIMPS more closely match the observations. So uncounted black holes with five sixths of all the matter in the universe aren't as feasible as a cloud of sub-atomic particles that clump together by gravity but don't form visible matter.

Very readable and easy to use a program included on the link: http://dl.dropbox.com/u/26262175/SagitariusBRprogramDescription.pdf , convincingly proves that the observed rotation speed of stars in galaxies, is the result of natural distribution of baryonic mass in the galaxy and this has nothing to do with dark matter.

The program is very ingenious and inventive, and can cause a lot of satisfaction to the user. I checked it out!

The absorption is to a virtual state and is unable to transfer momentum or energy to the atom. The color and direction can't change.

 

Using permittivity and permeability is the classical explanation, purely in terms of electromagnetic waves. Different explanation, same result.

Does not that contradict your earlier explanation?

"The answer is that light does not really travel slower in water. What happens is that the light travels at c from water molecule to water molecule. When it interacts with a molecule, the molecule absorbs it and is excited to a higher energy level. After a short delay the molecule sheds that excess energy by emitting a photon ( no tthe same photon it absorbed, that photon was destroyed when absorbed, which heads off at c until it encounters a molecule. It is the accumulation of all these delays that makes it appear as if the speed o flight has been lowered."

As has been described (quantum mechanically): the photon travels at c, but spends some time being absorbed/emitted from virtual states in the atoms of the medium through which it travels. The reduction in the speed of light comes from the delay, not a change in the speed of a photon.

How then to explain that a ray of light in water, such as red, green or otherwise, does not change either its color or direction, and does not depend on the water temperature and the speed of its movement?

How does this relate to the formula on the speed of light in the medium: cm = 1 / (εμ) ^ 0.5

ε - permittivity of the medium, μ - magnetic permeability of the medium, cm - speed of light in the medium.

Has anyone wondered how it looked to the theory of relativity, in the world of bats?

Assume that in this world there is no light, and the bats know nothing about it.

The only medium to measure the speed and distance, are the waves of sound of their maximum speed of 340 m / s.

Do according to their theory of relativity, the speed limit for the particles, therefore, was to 340 m / s?

Do as it approaches of their vehicle to the speed of sound, would have also changed their time and mass in the same way as in SR?

Please do not use in considerations the speed of light, because for the bats it does not exist.

It doesn't matter what "your understanding" is when it is in conflict with actual experimental results.

 

To repeat what I said earlier. We can measure the kinetic energy of particles after they leave the accelerator.

 

If, as you claim, the inability of the accelerator was due to decreasing efficiency of energy transfer from accelerator to particle then the kinetic energy of the particle upon leaving the accelerator must be found by E= mv²/2. This means that the greatest amount of kinetic energy a proton could have upon leaving would be 470 mev ( by setting v=c). However, the RHIC has created protons, which after leaving the accelerator, have a KE of ~250 Gev (over 531 times the max KE possible by your claim.)

 

 

In addition, the amount of energy the accelerator consumes is related to the load it is placed under (the amount of energy is is transferring to the particle). Since the energy consumption of the RHIC corresponds to the KE of the proton leaving the RHIC, The RHIC is transferring that energy to the proton.

 

IOW, The accelerator expends X energy accelerating the particle, the particle has X measurable energy after leaving the accelerator. Thus the accelerator transferred X energy to the particle. Since X is many times greater than the maximum KE the particle could have had without undergoing an increase of relativistic mass, and matches what is predicted for a particle traveling at that speed with relativistic mass, the forced conclusion is that the particle undergoes an increase of relativistic mass.

 

Continuing to argue that your view is correct in the face of real experimental evidence to the contrary is the path to crankdom.

 

Sirs, I thank all of you for the interesting discussion.

No, that's not the basic or only evidence. It is part of the picture, though.

 

 

 

No, the constraints on making an accelerator work does depend on the relativistic corrections, i.e. relativistic mass.

 

 

 

 

The trajectory of the particle and the confining forces necessary to make the particle travel on that trajectory depend on the relativistic mass. If the relativistic correction was not present, the particle would have a different trajectory and the accelerator would not work. IOW, this bit of evidence is not dependent on energy transfer.

 

Also, the purported limit on the difference in the speeds ignores the possibility that the force is that of attraction, where the arithmetic difference in speeds does not tend to zero — it increases in magnitude. It also ignores that the speed of light is still c in the frame of the particle.

 

 

This is not true. I can distort the field in two regions simultaneously in remote regions such that d/t is infinite. As I stated before, it's not even true within a wave packet, despite your objection that it does not transfer energy. But this is all beside the point, since it's not related to the issue.

I do not understand your words, does this mean that in your opinion it is possible to convey signals (distortion) in the electromagnetic field, with any speed greater than c?

Deformation of the proton trajectories with increasing of its speed, may also be associated with the helical shape of its path and a necessary compensation of the increasing centrifugal force of the proton, in the helix, which requires a significant additional energy.

For clarity, I would like to present here once more my understanding of this issue:

How can you conclude this, given that the relativistic mass does increase and tend to infinity?

 

 

 

The phase velocity of an EM field is not limited to c.

For clarity, I would like to present here once more my understanding of this issue:

The basic hard evidence for the alleged increase in relativistic mass of particles (protons) in accelerators, is the fact that, despite the biggest increase of power of the electromagnetic field, accelerating these particles, the speed of the particles can not achieve the speed of light.

In my understanding, the reasons of that constraints in accelerators are other, and they do not depend on the particle mass.

These constraints are the following two laws of physics:

1. As the speed of accelerated particle (v), approaches to the speed of the propulsion system ©,which accelerates this particle, the amount of energy transferred from the propulsion system to the particle is decreasing, and is getting smaller and smaller with the decreasing of the difference between these speeds. Transfer of energy decreases to zero when the difference of the speeds tends to zero. This can be easily proved by a calculation.

Hence it is well known in accelerators, that if the speed of the proton is getting closer to c, then for a further increase of its speed , it must be used disproportionately more and more power of the propulsion, and that at smaller and smaller effects.

2. Any change or distorsion of the electromagnetic field can not travel faster than the speed of light.

Acceleration of the proton takes place not by the interaction of electromagnetic fields on the mass of the proton, but on its electric charge. Thus, the proton motion in an electromagnetic field of the accelerator is connected with the movement of its electric charge , which is the same the movement of an electromagnetic distorsion in this field.

On the above limitations of the particle speed, does not affect the size of power of the propulsion system, or the mass of this particle.

So the claim that the motion of particles in accelerators is the proof of the relativistic increase in mass, is not justified.

Phase velocity of an EM field is not limited to c.

The phase velocity does not transfer any energy.

The problem is that you are thinking about the way the energy is transfered in the wrong way. Here's a rough analogy:

 

You have a stream of water pushing a ping pong ball. You're arguing that the water can't make the ball move faster than it itself is. However, this is not how we accelerate particles.

 

Instead, think of putting the ping pong ball at the bottom of a vertical column of water. The ball will rise due to the buoyancy of the water. The force propelling it upward is from the water pushing in on it. As it rises, it finds more water already waiting for it to push it higher. This is like the electromagnetic field of the accelerator already being there fro the particle. It is not like the situation with the water stream is pushing from behind.

 

 

Besides we know that it isn't a matter of the accelerator transferring less and less and less energy to the particle as it approaches light speed, because we can measure the KE of the particle after it leaves the accelerator and smashes into the target.

Janus, thank you very much for your interesting explanations.

But I still have doubts:

The electromagnetic field in the accelerators does not work on the mass of the accelerated proton, but only on its electric charge, which itself creates a moving change in the electromagnetic field of the accelerators.

And we know that changes in the electromagnetic field have limited speed of c.

Therefore, as I understand it is not possible to propelling proton faster than c, and it is not due to increase in mass of a proton.

There are two reasons why this is wrong:

 

1) Only changes in the electromagnetic field travel at c; you could have a field that is constantly speeding the particles up.

 

 

 

2) It actually is possible to pull a faster object with a slower object. You just have to be creative in doing it.

=Uncool-

 

1. Moving particle with electric charge, itself constitutes a change in the electromagnetic field.

 

 

 

2. "Gravitational slingshot" is not a proof of the crossing by a spacecraft the speed limit for waves of the gravitational field, which accelerates the spacecraft.

 

Can you give another example for that?

Your understanding is wrong.

 

But there is another example that does not rely on the inability to accelerate particles up to c.

 

It is cyclotrons. They work by accelerating charged particles through a constant magnetic field. The magnetic field causes the particles to follow a circular path. At a certain point of the path charged plates give the particles a boost The charging of these plates has to be timed properly for this to work.

 

As the speed of the particle increases so does the radius of its path. The beauty of the system is that, at sub-relativistic speeds, the time it takes for a particle to complete one circuit around the cyclotron is independent of the radius of the path the particle follows. This means that as the particle accelerates, it moves out to a larger radius path and takes the same time on each pass to come back to the charged plates. This allows you to set a fixed frequency to the charged plates so that they give the boost at the right time.

 

However, at relativistic speeds, the increase in relativistic mass causes the radius/speed ratio to change. As the particle accelerates, the increase in relativistic mass causes it to make a larger circular path than it would otherwise, thus the time it takes to make a complete circuit is no longer constant, but gets longer and longer. The particles get out of sync with the timed signal to the charged plates and you've reached the limit of the cyclotron's abilities.

 

Note that this has nothing to do with the charged plates inability to accelerate the particles any further. This is illustrated by the next generation of accelerator, the synchrocyclotron. The synchrocyclotron adjusts for the changing particle mass by changing the frequency of the charged plate signals as the particle accelerates (or slowly changing the magnetic field). This keeps the charged plates and accelerated particles in sync, allowing for much higher accelerator velocities.

 

 

If it weren't for the increase in relativistic mass, a cyclotron would not have the limited capability it does.

The laws of physics prove, that if the speed (v) of the accelerated particles is closer to the speed © of the driving force, the energy transferred from the drive system to the accelerated particle is getting smaller. With the speed of the particles (v) approaching the speed of the driving force ©, the transferred energy tends to zero, and it is not depending on the size of the driving power.

So I can not understand, how you can exceed this speed in any system, breaking the basic laws of physics?

The answer is that light does not really travel slower in water. What happens is that the light travels at c from water molecule to water molecule. When it interacts with a molecule, the molecule absorbs it and is excited to a higher energy level. After a short delay the molecule sheds that excess energy by emitting a photon ( no tthe same photon it absorbed, that photon was destroyed when absorbed, which heads off at c until it encounters a molecule. It is the accumulation of all these delays that makes it appear as if the speed o flight has been lowered.

How then to explain that a ray of light passes through the clear water without dispersion? Absorption and emission of photons by molecules should be visible in the form of diffuse light, or maybe as the rainbow?

They might. What they can't is overtaking speed of light in vacuum( unless they have heard of neutrinos defying barrier or something.)

How it is therefore possible that with the same laws of physics, in an X environment can be light overtake impunity, and in the Y environment, not, because our mass is growing as fast as after the big burgers and beer?

A new look at dark matter and dark energy is uniquely presented in an interesting demo program available at link: http://dl.dropbox.com/u/26262175/SagitariusBRprogramDescription.pdf

 

I am interesting if anyone knows other educational programs on dark matter or dark energy which are available on the Internet?

 

 

The program shows that dark matter and dark energy are not needed to explain the equal speeds of the stars in galaxies and the expansion of the universe.

Suppose that somewhere in the universe is the civilization that exist exclusively in the underwater world, in which the speed of light is 230 km/s. The question concerns whether their imaginary underwater rockets can therefore overtake the light in their world?

 

Particle accelerators work.

According to my understanding, limited speed of particles in accelerators has nothing to do with the theory of relativity. Here applies the ordinary law of physics: " cart can not move faster than a horse that pulls the cart", and the horse in the accelerator is the electromagnetic field with a speed of its own c.

Are there any hard evidence that the relativistic mass of the rocket (or particles) increases with its speed ?

First, I'm going to make a request. Just use the default formating for your posts. The way you are formatting them makes it near impossible to read when using the quote function. The formating does not show and all you get is the format tags. It ends up looking something like this:

 

[tag] word[endtag] [tag] a few words[endtag][tag]word[endtag][tag]word[endtag]...

 

with sentences and phrases broken up by formating tags. This makes it very difficult to respond to your post point by point.

 

You might think it looks nice in the post, but trust me, nobody really cares about what the posts look like, only their content.

 

 

As to your post. It doesn't matter whether light or anything else exists in your scenario or not. It is the speed "c" that is important, that and the fact that it is invariant ( it's just handy to use light in many examples because it happens to travel at c).

 

The fact that c is a finite and invariant speed has consequences that extend past things that travel at c. Removing light from the scenario does not change this. The addition of velocities formula I gave is an example. The "c" is there because it plays a fundamental role in how the universe works.

 

c plays the role infinite speed was thought to play before Relativity. Then, infinite speed was the invariant speed. (in fact, if you replace c with infinity in the velocity addition equation, it reduces to u+v.)

 

So to repeat, we use light in many examples because it is convenient to do so, not because light is required for the principles in the example to work.

Many thanks Janus for your last explanation, and sorry for my formating. I will be better from now.

Many, many thanks Janus for your reply.

Sorry again, but I need your more explanation. Case 2 was designed as an exact physical equivalent of the case 1, where the car represents the rocket and the motorcycles (instead of it the sound may be considered) represent the light carrying messages. Other media do not exist, so in my understanding they should not occur in the calculations for the case 2. Therefore I do not understand how and why in your calculations for the case2, there exists a third medium in the form of c?.

Hi, I'm Bart, I'm not a physicist but I like to read news in astronomy, physics, and the CETI, which appear on the Internet and the physics forums. Some things I do not understand, or their current interpretation does not agree with my understanding of them. So I think that this forum will help me to dispel some of my doubts.

Janus, thank you very much for your explanations and sorry yet, but still I don't well understand the calculation of 1,15 days to planet C and 3,46 to planet A? That's means for the astronaut in the rocket, who knows the real distance to the planets, that his messages sent to planet C run at speed almost 1,8 times greater than light speed c, and to planet A only 0,58 of c?

What is the physical difference between the case 1 and case 2, below?

Case 1.

A rocketis moving at speed 0.5 c, from planet A to planet C, which are distant from each other by 4 light-days.

During the flight the rocket passes the planet B, located exactly halfway between planets A and C.

At the time of passing the planet B, from the rocket and from the planet B are simultaneously sent SMS messages to the planets A and C.

SMS sent from the planet B reaches the planets A and C at the same time, in two days.

Question, when the SMS sent from the rocket, will be received on the planet A and the planet C, respectively.

Case 2.

A car is moving at constant speed 0.5 v, from town A to town C, which are distant from each other by 4 motorcycle-days

On the way the car passes the town B, located exactly halfway between town A and C.

At the time of passing the town B, from the car and from the town B are simultaneously sent messages to the towns A and C, by motorcycles with an arbitrary set constant speed v.

The same question, when the message sent from the car, will be received at the town A and the town C, respectively? (in the same time)

According to the rest frame of the rocket, the signals sent from the both rocket and B arrive at planet C in 1.15 days and at planet A in 3.46 days. IOW, while the signals from both the rocket and planet B will arrive at each planet at the same time, the signals will not arrive at planet A at the same time as they do at planet C.

So how an astronaut in the rocket can understand that the signal sent at halfway between the planets A and C, comes to these planets at such different times, knowing that the planet B is exactly midway between the planets A and C and, that light travels at the same rate to the both planets?