Moving in the opposite direction / Having a zero Momentum frame.
As a matter of fact I have multiple degrees, but none of them are in physics.
I’m a plant manager not a physicist, but that doesn’t mean That I’m incapable of understanding the subject.
The problem with using relativistic mass is that it causes a lot of confusion. For instance RM has no application whatsoever in General Relativity, but on this board and others I constantly see people who think that gravity is dependent on it,
I have to disagree on the mass and energy thing. They definitely are not the same thing (a single photon vs. a system of photons), and one cannot be transformed into the other.
For instance what would be the sub atomic description of exactly what is happening during the process of converting mass to energy?
It’s not directly related, but it’s still about light; read this article. Apparently some scientists, I believe at CERN, put a beam of photons through cesium gas, and the photons went about 300c; effectively arriving before they were sent. Check this out; am I misreading this? http://www.pbs.org/newshour/bb/science/july-dec00/light_7-21.html
Does light have mass?
I didn’t even know light was Catholic! 
Oh, come on…someone had to say it!
And this: http://www.sciencenews.org/articles/20000610/fob7.asp
And this: http://www.soulinvitation.com/philight/ although that one’s way over my head.
Er, no. Consider the resultant of the interation between an electron and a positron. The products are photons. If mass and energy are not two different forumlations of the same fundamental quality, then where does the mass go and where does the energy come from?
I think the argument for a fundamental distinction betwen mass and energy is as disingeneous as the “particle/wave duality”. There is no duality; it’s just that it is mathematically convenient sometimes to describe the particle in terms of a single, indivisible chuck and sometimes as a quantitized wave. Similarly, depending on how you are measuring or observing an interaction, it may be more appropriate to speak of the “mass” of a particle or of its “energy”. If you are dealing with a mechanical interaction we’ll speak of mass, or momentum, or kinetic energy. thermodynamic effects, potential or binding energy is (generally) more appropriate.
We often speak of subatomic particles has having a “mass” in eV. No problem there. However, for practical purposes, it isn’t really very useful to speak of a photon’s “relativistic mass”, since you can’t measure its mass directly and it doesn’t jibe well with QM. However, we often speak of the momentum of a photon in terms of its vector and frequency in ways that are equivilent to m[sub]eff[/sub]v. Our daily interactions with photons lend themselves to a thermodynamic view in which the momentum of the particle is less important than the energy liberated by being absorbed and re-radiated, but there are situations, such as in the middle of a nuclear bomb, or the light pressure on celestial objects in which the momentum of a photon is a mechanical consideration.
Stranger
Jeez Stranger didn’t you read the thread? A system of photons with a zero momentum frame has mass.
The mass didn’t go anywhere it’s exactly the same as before the interaction and so is the energy. They’re properties of the system, and as long as you are consistent in defining the system its mass and energy cannot change.
A hot object is more massive than the same object cold.
A perfectly reflecting box with a photon bouncing around inside has more mass and higher inertia than the same box without the photon.
If a nuclear weapon is detonated in a vault the vault weighs the same before and after the detonation.
You can make this a little stronger, even. For any two photons which are not moving parallel to each other (that is, in exactly the same direction), there is some reference frame where they’re moving directly away from each other, and the net momentum is zero. So almost any system of two or more photons has nonzero mass.
As for the mass/energy distinction, I think it’s best to say that mass is a subset of energy. That is, all mass is energy, but not all energy is mass. For instance, suppose we look at a pion decaying into two photons. If we look at the pion as a system, it has energy, and all of its energy is mass. If we look at the two photons afterwards as a system, then it has the same amount of energy, and that energy is still all mass. So in that sense, you can never lose mass. But if we look at one of those photons at a time as a system, it has half the total energy, but that photon by itself has no mass. How much mass you have depends on how you define your system. And I think there is a practical distinctinction between the mass you have in the pion and the mass you have in the two-photon system afterwards: You can’t break up the pion into smaller subsystems each of which is individually massless, but you can do so with the two-photon system. This distinction is generally described in terms of “converting mass to energy”, an admittedly sloppy piece of terminology, but it works.
Oh, and appleciders, I don’t think you’re misreading that article, but the article is miswritten. There have been many experiments in the past few years which purport to show light travelling faster than c, but in all cases, it’s not, but just gives the appearance of it. In most of these experiments, a pulse of light is sent through a chamber, and the front end of the pulse exits the chamber before the back end of the pulse enters it. This, by itself, is completely, wholly unremarkable. The only thing that makes these experiments notable at all is that something in the chamber causes the pulse of light to change shape, so that the front of the pulse coming out looks like the back of the pulse did going in. So it looks like the back end of the pulse (or for that matter, any other part of the pulse) is coming out before it went in, which (if it were true) would be quite remarkable. But it’s only an illusion, caused by the way the pulse changes shape in the chamber.
Well Chronos I’m certainly not going to argue with you, but I still think the term is extremely misleading and I believe it’s intimating that something is occurring that that most definitely is not.
It causes people to think of mass as some sort of a thing that evaporates or something, and then energy pops out. Whereas in fission, for instance, it would seem that that it’s much clearer to envision the nucleus rearranging itself into a configuration of higher binding energy and thus releasing the decreased potential energy as electromagnetic and kinetic energy.
The local mass defect can then be considered as nothing more than the consequence of the energy release, not the cause. But nonetheless I see your point and it’s certainly a valid one.
.05.03.26
The mass (gravity) becomes an equi-valent amount of anti-mass (energy; anti-gravity). This transformation releases of a dimensional amount of stored energy.
IIANM; it now seems the anti-gravity released since creation is accelerating the expansion off our universe.
Peace through Liberty
r~
Wha–huh?
This is an attempt at a woosh, right?
Stranger
I may be mistaken, but I believe the data show the universe is not only expanding, but that the rate of expansion is accelerating. It seems to me that the idea that best fits, relies the existence of a “dark energy”. This dark energy must possess properties opposite gravity (anti-gravity?) to counter the Big Crunch.
Is it your understanding that visible energy does not share this property?
r~