Does light have "weight"?

Question

We understand light is made up of particles. A beam of light particles would have weight of some amount, if so could Light push or propel an object?

Answer 1

true, light doesn't fall into classical physics since light itself made up of the particles that make up atoms.

light isn't actually an atom thusly cannot display mass as we know it (as of yet)

light is energy and energy can be seen as mass, even converted in certain experiments..... you can transform matter <---> energy.

it only has mass at it moves thought.
light is said to not have any mass at rest.

an example of energy being seen as mass,

have you ever seen those glass bulbs that have a little weather vane looking thing inside with 4 paddles (black on one side white on the other) well, when light hits the white side of the paddle the whole vane spins......

thats because as the energy in light hits it, it pushes against it with the light's mass/energy.

Answer 2

Does Light Have Weight

Answer 3

It can, in a way. Classically, light has no mass, but DOES have momentum. Which is how the solar wind can move objects, like a solar sail.

People have been trying to measure the mass of light for decades (read the paper by Proca for more info). At the moment, we have an upper limit (it must be less than) 10^-61 grams per photon. There are many ways to test for light having mass, but so far, nothing.

Answer 4

Well, light can be viewed as a particle. But it's a massless particle.

On the other hand, a ray of light is "bent" when passing a massive object. And that could be viewed as one of the properties of a body that has weight.

So this means that I can't say "yes" and I can't say "no".
Gonna have to think about this one........

Answer 5

We already know that light can push or propel and object. All it needs for that is energy (which it is known to have).

Mercury's perihelion advance is explained (under Relativity) by the analogy that sufficienly dense light affect gravity as if it has mass (E = m c^2 becomes m = E / c^2 )

"Weight" is the response that mass has to a gravity field. Because we have mass, we are attracted by Earth. The surface is in our way and will press back to keep us from falling. This pressure is known as "weight".

Light is deviated by the presence of mass, showing that it can be subject to gravitational attraction. Some would use that to say that light has weight. It can only be used to show that light can act as if it had mass (alternatively, it can be used to show that the continuum is curved and light simply follows the curves).

However, if something gets in the way to keep it from falling, the light ceases to exist (its energy is absorbed) because light cannot exist at any other speed than the speed of light. So I say light has no "weight".

Your milleage may vary.

Answer 6

To answer your question, and to be on the safe side as to be sure you understand, and because it would be rude to answer your question in technical terms which some might not understand (common courtesy), the answer is NO.

See, light is made up of only protons, a part of an atom. Unlike neutrons and electrons (also part of an atom), it is weightless. Neutrons and electrons have a weight (oh so very little weight you have no idea haha), but the proton does not, so light is without weight. But it does have momentum since it travels at a speed.

Imagine water spraying onto your hand. It pushes your hand in whatever direction (down because of gravity-duh), and that's how you can think of pressure. That's the best way to describe it, but since water DOES have a weight, you gotta think of it like that somehow. Kind of like blowing of a super sensitive weight scale-it'll register weight because of that pressure. But now, because the scale is already set to compensate for the weight of the stuff in the air, now it is comparable to the pressure of light, because it won't pick up that weight, and now all there is left is the pressure, just like light.

So again, no, light is weightless :D

HOPE THAT'S HELPFUL AND MAKES SENSE!

Answer 7

One would not call it weight because that is a term from classical physics and does not apply.

But light has momentum and can push things, i.e. transfer its momentum. If it hits a mirror at right angle, it will transfer almost twice its momentum.

Light also gravitates (i.e. attracts other objects), but it would be very hard to find enough light anywhere to see that effect. But we know it is there and general relativity puts it into the equations at the right place.

Answer 8

This is a quite interesting question, and I have seen heated debates about the answer, because sometimes light behaves like a wave and sometimes light behaves like a particle.

Light itself is an enigma. It is deviated by the gravitational force of masive celestial bodies but if you catch a ray it doesn´t have weight.

So, to give a simple answer to your question, I would say it doesn´t have weight.

But I´ll leave a note:
We need to understand light better o give you the full answer.

Answer 9

Weight is a Force measured in newtons caused by an acceleration due to gravity.

F=(mass)(acceleration) becomes Weight=(mass)(acceleration due to gravity)

According to Newtonian mechanics the light particle has no mass and therefore is not affected by gravity and has no "weight"

However Einsteins relativity predicted that light waves are affected by gravity and are forced to move along a curved path just as matter is and therefore in that sense they do have a "weight". In fact this principle is what was used to prove the relativity theory when it was shown that light from a star that should not be visible because our star was in the way is actually forced around our sun due to gravity and is visible.

Answer 10

i think the opposite...since light has momentom or since the photon is a particle therefor it has mass. logically every partical of matter has a mass even it is equal to 10^(-999999999999999999) but it shoud have mass....also light is attracted by black holes which have a very big gravity, and no attraction without weight (but a=0 :D)