Comment by silicon2401 | Hacker News Reader

Comment by silicon2401 | Hacker News Reader

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Thanks for posting this comment, it was really entertaining to see how quickly it got wildly over my head and started sounding like sci-fi gibberish

> You can think of it, at a very high level, being the difference between a force mediator that has no self interaction (photon)

Don't really know what a force mediator is but I can somewhat imagine, and photons not interacting with themselves I think makes sense

> a force mediator that does have self-interaction (gluon)

I'm guessing these particles interact with themselves and maybe they're called gluons because they stick together or something, like glue

> Gluons interact with each other, whereas photons don’t.

I think I'm making progress

> Even this by itself isn’t naively enough to get all the strong force’s interesting behavior. But the math works out in such a way that when you start to pull two strongly bound particles apart,

Good so far

> the color field forms a flux tube of gluons between the two particles,

lost me, you just switched lanes into back to the future speak

>> the color field forms a flux tube of gluons between the two particles,

> lost me, you just switched lanes into back to the future speak

The way I interpreted this was that the interaction happens over a line beam (rather than a spherical surface) so it doesn't drop off as 1/r^2, but as 1 (i.e. constant). Which raised more questions for me (and made me wonder what the MOND case is), but I'm still digesting the comment.

>the interaction happens over a line beam (rather than a spherical surface) so it doesn't drop off as 1/r^2, but as 1 (i.e. constant). Which raised more questions for me (and made me wonder what the MOND case is)

To me the MOND is 1/r as i think the very weak gravity acting only in the plane of the galaxy disk is, very roughly speaking, a result of quantization - i.e. "not enough" gravitons to interact in all spherical directions and thus gravitational field basically exists only in that plane. It is like a mental experiment - say we generated a classic EM spherical wave yet of a very low energy of just one photon, and have several other charges placed at the same distance from the wave source - while the classical 1/r2 would have the wave interacting the same way with all the charges that would be a violation of energy conservation in our low energy "one photon" case where only one charge at best would get interacted with and thus it would look like supposedly violating 1/r2 law of the EM.

I think you're confusing 2 things. The "energy of a field", whether that's a magnetic field or gravitational field is fictional. It's potential energy.

In order to move from A to B you must "pay" the difference in potential energy between the 2 points in space. That payment can be negative (e.g. falling).

So if gravity increased in strength after ~2000 light years (which is the problem dark matter tries to solve) to 1/r instead of 1/r2 that would not represent any energy at all. It would not insert energy anywhere, into any particle, it only changes the "fictional" values of potential energy in a bunch of locations. Therefore it would not violate conservation of gravity.

Oh, and things form discs by default. If things fall into something, they form a disc shape. Round things are only formed once the collisions between stuff in the disc start going over a certain level. Galaxies are so incredibly low-density there are even a few galaxies that have multiple discs, but still very much discs. Only "small" things are ball-shaped, like stars and planets because the particles exert pressure on each other and the third dimension provides a way to relieve the pressure.

Is it because the force is affecting only a pair of particles instead of all like charge?

>> the color field forms a flux tube of gluons between the two particles,

>lost me, you just switched lanes into back to the future speak

Sadly, that's the most important part!

Basically, instead of imagining a field where the arrows go out in all directions, with gluons they mostly go straight toward the other gluon as you pull them apart.

So if you have two gluons, at -1 and +1, and a random gluon appears in between them at x, the graph of the force/pull of the gluon is close to a step function, correct?

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