Does light have mass and can this mass create inertia?

Answer 1

Light has no REST mass - but it does have RELATIVISTIC mass. The relativistic mass of light can be calculated from the energy of a photon E = h (nu) where h = Planck's constant and (nu) is the frequency of the light wave.

Then, set E = mc^2 = h (nu) to calculate its relativistic mass.

Yes, a photon has inertia as well! Einstein's theory of relativity, as experimentally shown, accurately predicts inertial properties of light. Light's relativistic mass is affected in the same way by the laws of physics as any other object's mass.

Answer 2

A New Limit on Photon Mass

A new limit on photon mass, less than 10-51 grams or 7 x 10-19 electron volts, has been established by an experiment in which light is aimed at a sensitive torsion balance; if light had mass, the rotating balance would suffer an additional tiny torque. This represents a 20-fold improvement over previous limits on photon mass.

Photon mass is expected to be zero by most physicists, but this is an assumption which must be checked experimentally. A nonzero mass would make trouble for special relativity, Maxwell's equations, and for Coulomb's inverse-square law for electrical attraction.

The work was carried out by Jun Luo and his colleagues at Huazhong University of Science and Technology in Wuhan, China ([e-mail], 86-27-8755-6653). They have also carried out a measurement of the universal gravitational constant G (Luo et al., Physical Review D, 15 February 1999) and are currently measuring the force of gravity at the sub-millimeter range (a departure from Newton's inverse-square law might suggest the existence of extra spatial dimensions) and are studying the Casimir force, a quantum effect in which nearby parallel plates are drawn together. (Luo et al., Physical Review Letters, 28 February 2003)

Answer 3

Light acts as both a particle and a wave as such it does have an effect on masses. This is the principle behind a light sail. In theory if you had a sail the size of Texas you could accelerate a payload to near light velocity. Light actually creates a pressure on the sail similar to a mirror reflection. The reflected light losses a small amount of energy when it reverses direction and passes the lost energy onto the sail.

Answer 4

Light has mass. There is a theoretical solar cell which could catch light to allow a ship to reach closer to the speed of light. Also, light is susceptible to inertia thus is must cause inertia. If light is shown into a glass of water, the light bends because the water has a heavier mass to pass through. If light didn't have it's mass, then it would just pass through without any affects.

Imagine, anything you see has mass. If it were not composed of mass, it would not be visible. (hence, light is visible. If not to the eye, then it's visible by instruments - spectrometers.)

Answer 5

Light has no mass, it's just wavelengths. Mass can create inertia.

Answer 6

I think that when god created light he was forced to make it very light so that it could travel as fast as possible so that nothing could catch up with it. This way it could be the undisrupted messenger of the universe and the universe's memory could be well preserved.

photons mass is 0 when not moving, but it has energy when moving... aren't they funny little things?

Answer 7

Light, or any other form of EM radiation, does not have mass. While is sometimes has particle-like properties (wave-particle duality) it is not actually a particle with mass, but rather a discrete packet of energy.

Answer 8

Light does not have mass, all its mass is in the energy state.

Answer 9

Light does not have mass or inertia. But it does have energy and momentum. Believe it or not.

Answer 10

I think the answerer above is confused. Light bends when passing through water because of refraction. That has nothing to do with any mass property of light.

The answer to your question depends on how you define "mass." With the usual understanding of mass, the answer is no. But there is another understanding of the term that you can read about here:

http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

and here:

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html