# A Creating mass (particles) from light

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1. Feb 13, 2016

### gabi

As far as I know both mass and energy affects space-time. Mass creates a "sphere like zone of distortion", the space-time is less altered as we move away from the center. Photons on the other hand alter the space-time rather wave like, along the propagation trajectory and not "locally".

Could it be that 2 colliding photons having the proper energy (very high energy actually) and proper colliding angle would start going around each other instead of continuing straight ? And if they would, is that "stable configuration of light chasing each other" what we call mass ? Because if we could shot 2 photons so they can start going around each other instead of going "straight" that means the space-time now would be locally altered (mass like) and it would somehow explain why mass can not be precisely located (in fact there are just two photon waves chasing each other on a sphere like surface)

2. Feb 13, 2016

### ZapperZ

Staff Emeritus
This is a very confusing post. The topic doesn't match the content!

If you are asking about creating mass from light in general (as reflected in the topic you created), then ask that! We know how to do pair-production already! This is not a mystery.

But in the second paragraph, you now talk about photon-photon collision, and then photons orbiting each other, which has nothing to do with "creating mass". So go back a bit. Have you looked into photon-photon collision phenomena in QED?

Zz.

3. Feb 13, 2016

### gabi

I think I was actually asking if mass at the most basic level is actually made of two photons orbiting each other. Or, could 2 colliding photons start orbiting each other ? If they could, would that be matter at the most basic level ?

4. Feb 13, 2016

### ZapperZ

Staff Emeritus
Then that question doesn't match the topic.

Secondly, can you figure out how much gravity it will require for 2 photons to have a geodesic curled in THAT small of a radius? It takes the gravitational field of something massive JUST to have a measurable effect on the path of a photon. Do a back-of-the-envelope calculation of how strong of a gravitational field that will produce that kind of a curvature, and see how realistic your scenario is.

Zz.

5. Feb 13, 2016

### gabi

I was thinking that though it would take a massive thing to change the path of a photon passing by at a distance of let's say 1Km, it would however take a much smaller one to change the path of a photon which is really really close by ...

I guess then the short answer is NO ... :)
So, though mass can be created out of pure energy, it's not a bunch of photons orbiting around on a very small sphere like surface because photons (doesn't matter how many, doesn't matter how close) won't be able to distort the space time so much so they could start going round. So really no way though to shrink the distance so to make it work ? :)
Thanks

6. Feb 13, 2016

### ZapperZ

Staff Emeritus
That is just ONE problem with your scenario. You haven't even tackled other problems that arose out of the apparent violation of several conservation laws. For example, how do you get a net charge out of something made of only 2 photons. After all, if an electron is made up of 2 photons, what is the origin of its net charge? Secondly, how do you get an intrinsic spin of 1/2 out of those two photons, considering that each photon has a spin of 1?

These, and several others, are problems that you haven't even dealt with in that scenario.

Zz.

7. Feb 13, 2016

### gabi

Did not really mean it's mandatory to be 2 photons only, there could be a bunch of them actually, I was only asking if it's possible to see matter as a lump of photons orbiting around ...
To be honest I did realize there would be a problem getting charge out of it but got them one at the time :)

8. Feb 13, 2016

### Staff: Mentor

There's no way to "add" any number of integer spins (e.g. spin 1 for the photon) to produce a half-integer spin, even when you include orbital angular momentum which is also integer (not half-integer).

9. Feb 13, 2016

### gabi

thanks for the answers, can't blame a non-physicists for trying a simpler model :)

10. Feb 13, 2016

### ChrisVer

still no matter how many times you add 0, you won't get the result q...

11. Feb 14, 2016

### Luiz Silveira

The idea gabi has would involve generating a stationary orbit (with distances in the Fermi nucleus radius and beyond) of a number of photos. This energy concentration could very well develop a pair prodution environment: a neutron and anti-neutron pair. The neutron can promptly decay in a proton and electron.

This way, a number of high energy photons can produce a hydrogen atom and a anti-neutron.

12. Feb 14, 2016

### ZapperZ

Staff Emeritus
But that is NOT what he/she is proposing. Read the thread again. The proposal is to argue that a "particle" is composed of nothing more than bound photons!

BTW, a pair production can't happen in vacuum. It has to happen in the vicinity of a heavy particle to ensure momentum conservation. It is why we shoot gamma ray into, say, Be to create e-p pair. You can't create e-p pair from photons in vacuum.

Zz.

13. Feb 14, 2016

### gabi

Thanks for the follow up Luiz, as I have no proper training in physics unfortunately I can't really talk in your terms ... But the idea is something like that: a high number of photons colliding at a proper angle and having the proper energy could maybe evolve into a "swirl" like trajectory (once again, please excuse the non-physic like language) which can become stable and form the basic building blocks of matter.
I mean, energy waves (photons) would distort time-space and thus change the trajectory of some other photons they collide with. And if they affect each other then they could maybe start swirling instead of going straight, each its own way. Of course there has to be the proper arrangement there so to get a circular orbit (proper energy, proper incidence angle). If energy is not enough the space-time bending would not be enough for example and they would just deflect ...
Other guys here say the space-time distortion would be too small to make a difference but I was thinking if the distance is also very small then maybe what lacks in energy is compensated by the small distance ...

Of course this has to go further because sometime such arrangement should create charged particles too but I did not take it that far, for the start I was only interested if at least such an arrangement would be possible (I mean, could they ever start swirling around or there is no way and the whole idea is completely wrong)