Does light, theoretically, have any mass?

[Bisjac]

That's bad logic. Speed doesn't require mass, it just requires any thing (even a theoretical mass-less box) move a certain distance over a certain amount of time relative to something else. Mass doesn't not factor into it.

you are talking about gravitational mass. (that technically we still dont know for sure exists the way we think it does)

light has inertial mass.

anything that moves (light) has a mass.
if it werent true, then even gravitational pulls wouldnt be able to bend and move it (and they do)

[Ad Bot]

[Nexus]

Light has momentum but no mass.  The things you learn about momentum and velocity in first year physics are actually just simplifications made for your own convenience about how they actually behave.  Momentum is more intrinsically related to the wavelength of the object than the mass and velocity.  Also just because an object has mass doesn't mean that it has a maximum momentum (such as mass times the speed of light).  Momentum will approach infinity as velocity approaches c.  Momentum simply being M*V only applies at non-relativistic speeds.

[Stocking]

Light has no mass, photons have no mass. They have ENERGY. Gravity acts on ENERGY

gravity doesnt act on energy. if something is really hot or really cold it will have no affect on its gravity or the effects of gravity on it.

light does have mass, because photons are particles. that's why gravity can affect light.

[Nexus]

gravity doesnt act on energy. if something is really hot or really cold it will have no affect on its gravity or the effects of gravity on it.

light does have mass, because photons are particles. that's why gravity can affect light.

Actually false on all accounts.

Warmer objects do in fact experience increased gravitational attraction although by a negligible amount since c^2 >> s*dt.
Gravity acts on relativistic mass, which includes energy.
Photons are in fact completely massless particles.

[Stocking]

Actually false on all accounts.

Warmer objects do in fact experience increased gravitational attraction although by a negligible amount since c^2 >> s*dt.
Gravity acts on relativistic mass, which includes energy.
Photons are in fact completely massless particles.

photons have relativistic mass

[Nexus]

photons have relativistic mass

Because they have energy.
Note that due to relativity, traditional mass is defined as "rest mass" for any given object.  For photons, this "rest mass" is defined to be zero.
Relativistic mass in generally measured in electron volts, and not kilograms or any equivalent unit.

[ABlockOfCheese]

No, it does not. Otherwise all the light would bend towards the ground.
Large amounts of gravity can distort light, but by very slim amounts. That has to do with more complicated stuff, though.

thats like saying you aren't affected by gravity unless you are more than 100lbs.  There isn't a theoretical wall of gravity that has to be broken before the light is affected by it.  It is affected by gravity period.  The reason it doesn't fall straight to the ground is because it is moving at such an insanely high speed.  It passes by Earth too fast to "fall down".  It isn't fast enough, though, to escape a black hole.

I guess this poses the question would light have any measurable mass if we were able to theoretically stop a photon and measure it.  We know that light travels faster in a vaccum than it does in earths atmosphere so it apparently is colliding with the molecules in the air, but further I can't really elaborate on it because it's beyond my realm of knowledge.

[BluetoothBoy]

Just wondering, how many of you have taken first year physics, let alone advanced physics? And how many of you are reading stuff on Wikipedia and then posting here (or just plain and simply are making these things up)?

[Ceist]

Light has momentum but no mass.  The things you learn about momentum and velocity in first year physics are actually just simplifications made for your own convenience about how they actually behave.  Momentum is more intrinsically related to the wavelength of the object than the mass and velocity.  Also just because an object has mass doesn't mean that it has a maximum momentum (such as mass times the speed of light).  Momentum will approach infinity as velocity approaches c.  Momentum simply being M*V only applies at non-relativistic speeds.

for a mass then (say a brick) to move at the speed of light would require an infinite amount of energy. from our current understanding of the universe, that's not possible.

Just wondering, how many of you have taken first year physics, let alone advanced physics? And how many of you are reading stuff on Wikipedia and then posting here (or just plain and simply are making these things up)?

i've only taken an intro to physics during my freshman year.
i read a lot on certain physics, mostly specific particles, neutrinos, higgs-boson, photons. i haven't found a good place to really start learning from the beginning of physics until recently.

[BluetoothBoy]

for a mass then (say a brick) to move at the speed of light would require an infinite amount of energy. from our current understanding of the universe, that's not possible.
i've only taken an intro to physics during my freshman year.
i read a lot on certain physics, mostly specific particles, neutrinos, higgs-boson, photons. i haven't found a good place to really start learning from the beginning of physics until recently.

It's also not possible for anything but the speed of light to reach the speed of light; therefore, the universe has no qualms. Also, I suggest reading up on Einstein's Theory of Relativity and spacetime. It gives a different view of how gravity might work, and it tends to follow the things we observe in the universe more closely than other theories.

[Måster Blåster]

Oops, I misread 'mass' in the title as 'ass'.

[Mariofan1701]

its why my goddamn scale is off 10 lbs each time

[Hammereditor^2]

Light is not matter.
"Matter" is any particle which takes up space and has mass.
Therefore, photons do not have mass.

[ABlockOfCheese]

Well anything that has mass cannot reach the speed of light so I guess light is massless.

[Ceist]

Light is not matter.
"Matter" is any particle which takes up space and has mass.
Therefore, photons do not have mass.

this statement makes no sense.