/sci/ - Science & Math

>>10538842
You can't go at c with rest mass.

>>10538842
while technically not proven, it would basically break everything if they had mass.
There are also upper limits on any possible mass. For example:
https://www.sciencedirect.com/science/article/pii/S0370269316301083

>>10538842
>it would basically break everything if they had mass
this is wrong, nothing would change. the literal speed of light could be less than the theoretical speed limit we call the "speed of light" and if that were the case, literally nothing would be different

>>10539083
We would have the change the standard model to give them mass and that could break things

>>10539083
No, it would imply gauge theory is wrong, which would basically break everything.

>>10539083
>nothing would change
except for Coulomb's law
and would mean that photons decay into smaller particles

>>10538894
Let's assume current value of c is not right and photons might actually have mass. It will explain so many weird observations we have about photons like photon momentum and why light can't escape blackholes.

>>10539257
>It will explain so many weird observations we have about photons like photon momentum and why light can't escape blackholes.
we've already have an explanation for that for like 100 years

>>10539273
>citations?

>>10539126
can you cite this claim?

all i could find when i tried researching this was that:

1) if light had non-zero mass then c in general relativity wouldn't signify the actual speed of light, just the theoretical upper limit we now call the "speed of light"

2) some shit with coulomb's law that doesnt really change anything

also i mean since a perfect vacuum doesnt exist, light literally doesnt even travel at c anyway

>>10539163
>except for Coulomb's law
>and would mean that photons decay into smaller particles
so nothing. a more accurate measurement of coulomb's law and knowing particles are going to decay long after everything in the universe is ripped apart really doesnt change anything

>>10539154
Nothing would break. All it would do is show us if we're wrong so that we can hurry up with finding the truth instead of dwelling on flawed ideas.

>>10539449
>it doesn't change anything
>here's things that would change
>yeah whatever who cares
nice

>>10539126
>that could break things
you scared of a new paradigm anon?

>>10539449
well there is a research paper on possibility of photons decaying into particles that travel ftl

>>10539472
are you retarded? do i really have to explain how words work to you?

>>10539564
link?

>>10539603
>are you retarded?
are you? someone claimed that nothing would change. someone else gave things that definitely WOULD change. you then brushed it aside because it isn't that big of a deal. just because it may not change the entire universe doesn't mean that it isn't worth pointing out.

>>10539603
https://www.livescience.com/38533-photons-may-emit-faster-than-light-particles.html

>>10538842
When people say mass they usually mean rest mass or invariant energy of a particle. Photons have energy though, as a function of their frequency, so you could say they have a relativistic mass, and since they are theorized to never be at rest in any frame of reference, they always have a 'mass'. I'm not sure we have measured exactly that light has zero mass but I would assume it would be very difficult to find experimentally while also having to find more and more exact values of Planck's constant. There havent been any experimental inconsistencies that have led us to think think otherwise, so assume their 'masslessness' is pretty certain at the moment.

Are photons the only massless particles out of there?

>>10538842
>Do photons have mass?

No. They don't.

It photons do have nonzero mass, it is experimentally constrained to less than 10^-18 eV/c^2. This is insanely small even by particle standards. Realistically, given the theory, we can confidently say it's 0.
http://pdg.lbl.gov/2009/tables/rpp2009-sum-gauge-higgs-bosons.pdf

>>10540939
If* photons do have nonzero mass

>>10540939
For reference, protons and neutrons are about 10^9 eV/c^2, and electrons are about 5*10^5 eV/c^2

>>10539083
The anon doesn't mean it would break the universe
He means it would break out current theories and models for physics (badly) and 120 years of work would go down the drain

If photons don't have mass, why are they pulled in by black holes?

>>10541379
Warped spacetime

>>10539366
>The theory of Special Relativity
>The theory of General Relativity

>>10541418
But are they trapped forever? So inside the black hole it must be really bright?

>>10541418
So that means space-time must have mass?

this thread causes me almost tangible pain

>>10539678
Read the article. The particles are "FTL" in the literal sense >>10539083 not the violate causality sense.

>>10541493
>almost tangible
Does it have mass?

>>10538842
Photons are generally considered to have relativistic mass, but no rest mass, however most decent upper level books footnote the no rest mass description and say, "*or may have a very tiny rest mass".

I'm in the camp that they do have small rest mass, as it fixes so many inconsistencies. And it's not the worst to implement as it just bumps the speed of light by some small %, say, 1 billionth or smaller.

>>10538842
bosons are considered non-material and massless unless they are converted into fermions. a example being solar power. personally tho i don't agree with it... im just parroting their work

>>10541634
>bosons are considered non-material and massless
Helium isotopes beg to differ.

>>10541479
It has energy

I don't get how we can even receive photons from other stars.
If you cover a sphere in dots and pull lines from every dot you can simulate photons leaving stars but that should leave "holes" just few kilometers over the surface.

>>10541479

That's why we tried to cancel out vacuum energy with supersymmetry. Then we discovered Dark Energy and it ruined our game.

>>10541785
true but where those lines are is random and changing constantly. So when we're farther away, on average we get fewer of them per time period, hence far away stars seeming dimmer

>>10541574
hehehe

>>10540269
gluons too
all gauge bosons should be massless, but the higgs mechanism breaks SU(2) symmetry, giving mass to W and Z; the fact W and Z bosons have mass is what predicted the existence of a higgs boson

>>10541785
cos its a wave like gravity in this respect numbnuts, where the strength of the field falls off by an inverse square law

>>10541873
If you increased energy levels to where forces unify they decouple from the higgs field and can't into mass.

>>10538842
We know from experiments that

E = mc2/sqrt(1-v2/c2)
E*sqrt(1-v2/c2) = mc2
1-v2/c2 = mc2/E2

When v=c the lefthand side becomes zero. Since c and E are not zero, m must be zero.

>>10542371
From what experiments?
Also, E -> inf?

>>10539408
Well lets go just check up on the standard model... and the answer is yes.

>>10544292
E->infinity makes no sense. Work is difference in energy and any difference from infinity is infinite.

Pretty much every experiment involving GR and photons (gravitational lenses, GPS,...) since it's the 00 component of the energy-momentum tensor for arbitrary speed.

>>10539408

1) lightspeed as a fundamental limit is a misnomer. It's the speed of action that is limited. Actually, if you use rapidity instead of velocity all these counter-intuitive things disappear and it can become infinite.

2) light having mass will change everything. It would mean that electromagnetic force has finite reach. Atoms would fall apart.

Light is always as fast as light, there's no slowing down in media or anything. You just perceive it as that since the phase velocity changes due to interactions in the medium, but the group velocity always stays the same.

>>10544415
>the group velocity always stays the same.

https://www.mathpages.com/home/kmath210/kmath210.htm
>In a medium whose refractive index is constant, independent of frequency (such as the vacuum), we have dn/dk = 0 and therefore the group velocity equals the phase velocity. On the other hand, in most commonly observable transparent media (such as air, water, glass, etc.) at optical frequencies have a refractive indices that increase slightly as a function of wave number and (therefore) frequency. This is why the high frequency (blue) components of a beam of white light are deflected more than the low frequency (red) components as they pass through a glass prism. It follows that the group velocity of light in such media (called dispersive) is less than the phase velocity.

>...Any modulation will propagate at the group velocity, which, in dispersive media, is always less than c.

If light is refracted through water... does water contain little black holes?

>>10544457
Oops, switched group and phase velocity. My point still holds.

Photons are particles. So of course they have mass.

>>10544527
Phase velocity also changes based on the medium.

>>10538842
>does light bend because of gravity
yes

>what dies gravity attract
mass

hmmm

>>10538842
Photons aren't necessarily real. More likely we just don't understand electromagnetic radiation.

So much bullshit in here. Light is always traveling at lightspeed and it has no mass. Gravity is caused by energy (including mass energy mc^2) and momentum and attracts the same.

>>10547420
you know too much. you'd best be quiet if you know what's good for you...

Is it possible for a massless particle to carry a charge?

Technically no but they still have momentum so firgure that one out