Matter creation

[nirjharmishra2004]

How that is Photons increase the mass of an object that absorbs it, if the photons have no mass?

Since all reactions in Chemistry can always go 'both ways' and be reversed no matter how improbable the odds for one side of the reaction vs. the other, it seemed logical to me that if nature/chemistry is this way, perhaps mass to energy is this way as well? We know Mass converts to energy, how can we be certain that with enough energy under the right circumstances we might not be able to create mass from energy? m = E/c²

How that is Photons increase the mass of an object that absorbs it, if the photons have no mass?----http://en.m.wikipedia.org/wiki/Matter_creation-------

[ajb]

We have things like pair production.

 

Though remember that there is no such thing as pure energy, so it is not like one can create mass from 'just' energy. The process must respect all the conservation laws of the standard model.

 

Anyway, more generally we know that when dealing with energy of a system we always need to take into accout the mass. You should also look up binding energy.

 

I hope the links provide you with some useful information.

[Strange]

How that is Photons increase the mass of an object that absorbs it, if the photons have no mass?

 

There are two different things here. Firstly, photons have energy and, as relativity shows, mass and energy are equivalent. So if you add energy to something then it also gains mass.

 

The second thing is changing photons into matter (and matter into photons - e.g. when matter and antimatter annihilate). This again depends on the equivalency of mass and energy.

[swansont]

 

So if you add energy to something then it also gains mass.

 

Except kinetic energy for center-of mass motion (i.e. KE that results from having linear momentum). Because of how we do the bookkeeping.

[Enthalpy]

It's not only that mass and energy would "convert" in an other. Every energy has mass, if not necessarily rest mass (beware vocabulary difficulties here) - that is, it has inertia, creates gravitation, and is sensitive to gravitation.

 

The usual example of nuclear fission is in fact electrostatic energy (the repulsion among the protons) converted to kinetic energy of the fission fragments. Other energy forms like heat, chemical energy... also have a mass, but as these are less concentrated than nuclear energy, this mass is less obvious.

[swansont]

Energy does not have mass. Energy is a property, as is mass. An entity can have energy, and can also have mass. An entity with mass will also have inertia.

[bluephysics]

 

Except kinetic energy for center-of mass motion (i.e. KE that results from having linear momentum). Because of how we do the bookkeeping.

So in reality, that line between kinetic energy and mass is nonexistent, but we consider that it isnt equivalent since it wouldnt work with our equations and numbers, or how we describe physics with our language and number system?

[swansont]

So in reality, that line between kinetic energy and mass is nonexistent, but we consider that it isnt equivalent since it wouldnt work with our equations and numbers, or how we describe physics with our language and number system?

I don't know what "in reality" means here. You are free to try and construct a system with a different protocol. But if you want to discuss the system we have already, KE and mass are separate forms of energy.

[Enthalpy]

Energy does not have mass. Energy is a property, as is mass. An entity can have energy, and can also have mass. An entity with mass will also have inertia.

And energy has inertia, and it creates gravity. We had already this discussion.

[Mordred]

Energy is the property of an object, particle or system to perform work. It is not a thing unto itself. Just like mass does not exist without being the mass of an object, particle or system.

 

To state energy has momentum is garbage. It would be like stating momentum, charge, force etc can exist on its own

Edited June 17, 2016 by Mordred

[StringJunky]

And energy has inertia, and it creates gravity. We had already this discussion.

Energy is property unto itself; how can it have another property? For it to have inertia as well it would be an object. Objects have properties; it doesn't make sense that properties have properties.

Edited June 18, 2016 by StringJunky

[Enthalpy]

We had a similar discussion already.

 

Take for instance a photon. It changes its direction, hence momentum for a distant observer, when passing by a galaxy. The conservation of total momentum tells that the galaxy has changed its momentum too due to the photon passing by, hence this photon creates gravity, and by its energy since it has no rest mass.

 

If you prefer to formulate it like "any single form of energy contributes to the inertia and gravitation of any kind of related object" instead of "energy has inertia and creates gravity", I don't mind - "energy" is only shorter than "any form of energy". Just don't forget electromagnetic fields among said "objects", independently of the particle that created it.

[swansont]

We had a similar discussion already.

 

Take for instance a photon. It changes its direction, hence momentum for a distant observer, when passing by a galaxy. The conservation of total momentum tells that the galaxy has changed its momentum too due to the photon passing by, hence this photon creates gravity, and by its energy since it has no rest mass.

 

If you prefer to formulate it like "any single form of energy contributes to the inertia and gravitation of any kind of related object" instead of "energy has inertia and creates gravity", I don't mind - "energy" is only shorter than "any form of energy". Just don't forget electromagnetic fields among said "objects", independently of the particle that created it.

 

 

The photon — that's what has the energy. The photon is affected by gravity. If you can give an example where it's just energy that's not a property associated with something else, then you're onto something.

[Enthalpy]

Then we have converged to a common opinion. I don't care too much about distinguishing "energy" from "any form of energy".

 

What carries the energy and the associated inertia change resulting from interaction is still a mystery to me. These ramblings

http://www.scienceforums.net/topic/85377-relativistic-corrections-to-hydrogen-like-atoms/#entry891647

seem to tell that the electron doesn't carry half of the variation of inertia resulting from its electrostatic interaction with the nucleus.

And there, it's more than semantics. Experiment goes against simple comprehension.

[Sensei]

The photon that's what has the energy.

Obviously. Where is no photon, electron, or other particle, there is nothing that can transfer and deliver energy from one place to another (from one particle to other particle).

 

But,

In the one frame of reference photon has energy/frequency:

[math]E=E_0*(1\pm v_1)*\frac{1}{\sqrt{1-\frac{v_1^2}{c^2}}}[/math]

[math]f=f_0*(1\pm v_1)*\frac{1}{\sqrt{1-\frac{v_1^2}{c^2}}}[/math]

(Relativistic Doppler effect: redshift/blueshift)

 

In the second frame of reference the same photon could have energy/frequency:

[math]E'=E_0*(1\pm v_2)*\frac{1}{\sqrt{1-\frac{v_2^2}{c^2}}}[/math]

[math]f'=f_0*(1\pm v_2)*\frac{1}{\sqrt{1-\frac{v_2^2}{c^2}}}[/math]

 

In the third frame of reference the same photon could have energy/frequency:

[math]E''=E_0*(1\pm v_3)*\frac{1}{\sqrt{1-\frac{v_3^2}{c^2}}}[/math]

[math]f''=f_0*(1\pm v_3)*\frac{1}{\sqrt{1-\frac{v_3^2}{c^2}}}[/math]

 

etc. etc.

 

Who is right, without absolute frame of reference (of some kind).. ?

 

Every observer, looking at the same photon, from different frames of reference, tells completely different energy/frequency/wavelength of the photon..

 

Property does not change, from different perspectives, charge remain the same, invariant regardless of frame of reference transformation..

 

The photon is affected by gravity. If you can give an example where it's just energy that's not a property associated with something else, then you're onto something.

In the one frame of reference, there is so much Relativistic Doppler effect blueshift, that there is pair production, and photon is converted to pair of matter-antimatter,

in other frame of reference, photon has not enough energy, and there is just Compton effect,

or in yet another frame of reference, the same photon is simply "photon in visible spectrum"..

Or in extremely redshift, radiowave?

 

In the first case, newly created matter-antimatter, are source of gravity:

1) we can take just their rest-mass into account

2) we take their relativistic-mass, then in what frame? Relativistic FoR will have much more energy thus mass than rest-mass, causing issue while calculating gravity..

Edited June 23, 2016 by Sensei

[swansont]

 

 

In the one frame of reference, there is so much Relativistic Doppler effect blueshift, that there is pair production, and photon is converted to pair of matter-antimatter,

in other frame of reference, photon has not enough energy, and there is just Compton effect,

or in yet another frame of reference, the same photon is simply "photon in visible spectrum"..

Or in extremely redshift, radiowave?

 

 

The frame is not arbitrary, since this has to happen with a massive particle around. You have to include its energy and momentum as well. One photon can't form a matter/antimatter pair on its own.

[imatfaal]

 

...One photon can't form a matter/antimatter pair on its own.

 

Is that because the pair alone cannot satisfy both conservation of energy and conservation of momentum at the same time - or is there another (more fundamental - is there anything more fundamental?) reason that this cannot occur?

[swansont]

 

Is that because the pair alone cannot satisfy both conservation of energy and conservation of momentum at the same time - or is there another (more fundamental - is there anything more fundamental?) reason that this cannot occur?

 

 

That's it. If you conserve momentum you don't conserve energy, and vice-versa.

 

The described problem is similar to the black hole scenario; if a mass is moving fast enough, will it form a black hole? No. If it can't form one in one frame, it can't form one in all frames. But you can't exclude parts of the problem from your analysis.

[Markus Hanke]

we take their relativistic-mass, then in what frame? Relativistic FoR will have much more energy thus mass than rest-mass, causing issue while calculating gravity..

 

 

The source term in the gravitational field equations isn't mass, energy or even relativistic mass - it is the full stress-energy-momentum tensor. This is a frame-independent quantity, so all observers agree on it.