Is the Photon Mass Really Zero or Does It Have a Finite Value?

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The discussion centers on the mass of photons, with participants debating whether photons truly have zero mass or a finite value. While photons are defined as massless particles that travel at the speed of light, some argue that their energy, calculated using Planck's formula, suggests a small but finite mass. The conversation highlights misconceptions about Einstein's equation E=mc², noting that it does not apply directly to massless particles like photons, which possess momentum instead. Additionally, the idea that a massless particle would travel at infinite speed is challenged, emphasizing that light from the sun takes time to reach Earth, contradicting the notion of a zero-distance universe. Overall, the thread underscores the complexity of photon properties within the framework of modern physics.
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Photon is the sub-atomic particle that light is made of. The properties of Photon:
Mass = 0, Charge = 0, Spin = 1.

According to Einstein's relativity, light travels fastest at 300,000 km / sec. When any other object travels at the speed of light, the universe shrinks to zero distance. But, we know that it takes 8.3 minutes for light from the sun to reach earth. So, even for sun light, the universe does not shrink to zero.

I find it hard to believe that photon has no mass. The energy of a photon is h x λ (Planks constant multiplied by Frequency) is roughly 10-20 Joules, small but finite.

According to Einstein, E = mc2. In a nuclear reaction, the mass lost is converted to energy which is carried by photon. Consider a hypothetical experiment, where photon is converted to a truly mass-less energy "particle". In the experiment, the mass of a photon is converted to pure energy. In short, the mass of the photon is lost. The lost mass is equivalent to the energy calculated by Planks formula (proportional to its frequency). So, the mass of a photon is 10-36 (small but finite).

If there was a mass-less particle, it would travel at infinite speed and can move from one end of the universe to the other end of the universe in zero time. For a truly mass-less particle, the universe would truly shrink to zero.
 
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vijayst said:
But, we know that it takes 8.3 minutes for light from the sun to reach earth. So, even for sun light, the universe does not shrink to zero.

You seem to be working in the frame of a photon. This is not possible in physics.

I find it hard to believe that photon has no mass. The energy of a photon is h x λ (Planks constant multiplied by Frequency) is roughly 10-20 Joules, small but finite.

According to Einstein, E = mc2.

This is not the actual formula. The formula is fine for slow moving objects, but not for things like photons.

If there was a mass-less particle, it would travel at infinite speed and can move from one end of the universe to the other end of the universe in zero time. For a truly mass-less particle, the universe would truly shrink to zero.

This is completely false and contrary to mainstream physics. Please do not write things like that.

Some things to read:
https://www.physicsforums.com/showthread.php?t=511175
https://www.physicsforums.com/showthread.php?t=511173
https://www.physicsforums.com/showthread.php?t=511170
https://www.physicsforums.com/showthread.php?t=512541
 
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vijayst said:
According to Einstein, E = mc2.

The full form of the equation is e2 = m2c4 + p2c2, where p = the momentum of the an object. Photons do not have mass, but they do possesses momentum. So even when the mass is zero, you still have a finite amount of energy.

You can check that here: http://en.wikipedia.org/wiki/Photon#Physical_properties
 
Thank you, micromass, Drakkith. It is 17 years since I last read a formal textbook in physics. I recently got interested in Particle Physics. One of the YouTube video misled me to come to the above conclusions.

As you rightly pointed out, I should have warned the reader that I was trying to prove a claim.
 
vijayst said:
One of the YouTube video misled me to come to the above conclusions.

You better avoid youtube videos and watch some nice lectures. Sometimes, youtube videos tend to mislead others
 
vijayst said:
Photon is the sub-atomic particle that light is made of. The properties of Photon:
Mass = 0, Charge = 0, Spin = 1.

According to Einstein's relativity, light travels fastest at 300,000 km / sec. When any other object travels at the speed of light, the universe shrinks to zero distance. But, we know that it takes 8.3 minutes for light from the sun to reach earth. So, even for sun light, the universe does not shrink to zero.

I find it hard to believe that photon has no mass. The energy of a photon is h x λ (Planks constant multiplied by Frequency) is roughly 10-20 Joules, small but finite.

According to Einstein, E = mc2. In a nuclear reaction, the mass lost is converted to energy which is carried by photon. Consider a hypothetical experiment, where photon is converted to a truly mass-less energy "particle". In the experiment, the mass of a photon is converted to pure energy. In short, the mass of the photon is lost. The lost mass is equivalent to the energy calculated by Planks formula (proportional to its frequency). So, the mass of a photon is 10-36 (small but finite).

If there was a mass-less particle, it would travel at infinite speed and can move from one end of the universe to the other end of the universe in zero time. For a truly mass-less particle, the universe would truly shrink to zero.

You should phrase your statements as questions. That way it doesn't sound like you think you understand something that you really don't.
 
adjacent said:
You better avoid youtube videos and watch some nice lectures. Sometimes, youtube videos tend to mislead others

I vote for less avoidance and more participation so that more people are exposed to real Science. Granted, it can seem an often thankless "job" but it's difficult to argue that it is ignore-worthy.
 
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