Do Photons Have Mass Despite General Relativity?

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Discussion Overview

The discussion centers around the nature of photons, specifically addressing whether they possess mass and how this relates to concepts in general relativity and gauge theory. Participants explore the implications of photons being massless and their role in electromagnetic interactions, while also touching on the philosophical aspects of purpose in fundamental particles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Evenus1 questions how photons can have zero mass, suggesting a belief that all entities must possess mass to be real within the framework of general relativity.
  • Anorlunda clarifies that not everything needs mass to be real, using photons as an example of massless particles that are nonetheless real.
  • Another participant emphasizes that all particles have energy, and mass is a form of energy when a particle is at rest, noting that photons are always in motion and thus have energy without mass.
  • A participant discusses the concept of purpose in science, arguing that fundamental particles like photons do not have inherent purposes, contrasting them with human-made objects.
  • One participant explains that photons are gauge particles and discusses the concept of gauge symmetry, suggesting that if photons had mass, it would disrupt this symmetry, which is essential for long-distance electromagnetic interactions.
  • There are multiple mentions of the participant's age and educational context, with some light-hearted exchanges about their level of understanding and spelling.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the nature of photons and their mass. While some agree on the massless nature of photons and their role in electromagnetism, there is no consensus on the implications of this for broader concepts in physics or the philosophical aspects of purpose.

Contextual Notes

Some participants reference advanced concepts such as gauge symmetry and Maxwell's equations, which may not be fully accessible to all contributors. There is also a lack of clarity in communication regarding the participant's age and educational background, leading to some confusion.

Evenus1
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I am knew only in year 9 but am doing some research on photons and was wondering how they have a mass of 0 as I thought every thing had to have a mass to be within the realms of reality or general relativity.
but I might just be wrong and if so could you explain it to me simply why and the correct reasons.
Thanks
Evenus1
 
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Congratulations Evenus1 for thinking about such things at age 9.

No it is not true that everything needs mass to be real. You already have the number one example - photons. Photons are very real a
Yet they have zero mass.

It is better to think that all particles have energy. Mass is just the energy of the particle that remains when the particle is not moving (momentum zero). Photons never stop moving. They have energy, but no mass.

Later, you will learn that energy and mass are related.
 
Excellent question at your age. Anorlunda has addressed part of your question but I'd like to address the other part of your subject line "what is their purpose". In science, basically, fundamental things don't HAVE a purpose, they just exist. Purpose is something ascribed to those things by humans, but nature doesn't really care what we think it just does what it does. We say that light has the purpose of allowing humans to see, but nature creates photons whether we are here to use them or not.

That is, a baseball HAS a purpose because it is a macro object designed by humans FOR a purpose, but it is made up of fundamental particles called quarks and electrons and THEY don't have a purpose, they just exist. The goal of physics is to identify such fundamental objects and learn how they came about and how they work and how they interact with other objects to make up the universe we live in.
 
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hi its me agian i am not nine but 14 soz but in uk and there school system is in years not grades lol
 
Photons fit in as gauge particles. That is, they are what the electromagnetic field is made of. Light, radio waves, magnetism, electric charge, all of that involves photons.

They are massless because they have gauge symmetry. I know that sounds like so much gobble-dee-gook now. But basically, symmetry is the argument. If they had mass they would spoil this symmetry. And this symmetry is what makes electromagnetism a long-distance interaction. Or to put it another way, Maxwell's equations imply an interaction involving a massless vector field.

You probably won't make much traction on that at your level. You will need to study some calculus at least. You may get to start that in year 11 or 12 if you are keen.
 
Evenus1 said:
hi its me agian i am not nine but 14 soz but in uk and there school system is in years not grades lol
For someone 14 years old in UK, your knowledge of physics (English) is much above (below) average. No one's perfect, I guess. ;)
 
Demystifier said:
For someone 14 years old in UK, your knowledge of physics (English) is much above (below) average. No one's perfect, I guess. ;)
i don't understan your brackets they don't make sence
 
i am sort of trying to lern some basic calculus as. i need it for some of my algorithms
 
Evenus1 said:
i don't understan your brackets they don't make sence
He is saying

physics above average
English below average

This reflects the fact that your spelling is atrocious and your grammar is only slightly better.
 

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