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The_Thinker
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how come light does not have mass, we know e=mc^2, so what gives; why is it that light doesn't have mass or rather what is the explanation for light not having mass?
The_Thinker said:how come light does not have mass, we know e=mc^2, so what gives; why is it that light doesn't have mass or rather what is the explanation for light not having mass?
dextercioby said:Physics does rather poorly into explaining WHY Nature behaves the way it does..
The answer to your question lies in the definition of the "m" in that expression. The definition of "m" is a much discussed topic in most physics forums, this one being no diffferent.The_Thinker said:how come light does not have mass, we know e=mc^2, so what gives; why is it that light doesn't have mass or rather what is the explanation for light not having mass?
I have to disagree on that point.marlon said:This is a classical mistake in the way we need to look at physics. It is NOT the intention of physics to tell us why nature does what she does.
...In other words, the nature of the questions changed. The questions became more fundamental. "Why?" was added to the "What?" and "How?" and "Where?". Alan Guth was one of the young pioneers of the new cosmology, asking the Whys, and his Inflationary Universe theory provided many answers.
Crosson said:Look at the great "why?"s that physics has solved in the past. "Why do the heavens move as they do?" got the answer "by the same force that gives you weight".
Perhaps not in your eyes, but in mine.marlon said:as to pmp : why you disagree ? the text you posted doesn't say anything in my eyes...
pmb_phy said:That is why I disagreed. However I assumed you disagreed with this philosophy. Is that correct?
Pete
Newton said:In the case of quantum electrodynamics; gauge invariane demands that the photon be massless!
you may say "why is electromagnetism a quantum field theory, etc etc". but that is a DEEPER question. at this point we do not have an answer to that.
One of the fundamental properties of light is its speed, which is constant and independent of the observer's frame of reference. According to Einstein's theory of relativity, objects with mass cannot travel at the speed of light. Therefore, since light does not have a rest mass and travels at the speed of light, we say that it has no mass.
The concept of mass is defined as the amount of matter in an object. Through various experiments, including the Michelson-Morley experiment and the Compton scattering experiment, it has been determined that light does not have a measurable amount of matter. This supports the conclusion that light has no mass.
Although light does not have mass, it does have energy. This energy can be transferred to objects, causing a force to be exerted. This is known as radiation pressure and is responsible for the force of sunlight on the Earth's surface, as well as the force of laser beams on small particles.
Even though light has no mass, it still has energy, and energy is affected by gravity. This means that light can be bent or redirected by massive objects, such as stars and galaxies. This phenomenon is known as gravitational lensing and has been observed by astronomers.
There is currently no evidence to suggest that light can have mass. However, some theories, such as string theory, propose that light may have a tiny amount of mass, but it is too small to be measured by current technology. This is still a topic of ongoing research and debate in the scientific community.