The discussion revolves around the mass of photons, phonons, and electrons, exploring concepts of rest mass, energy, and the behavior of these entities in different contexts. Participants engage in clarifying definitions, addressing misconceptions, and examining the implications of mass in various physical scenarios.
Participants generally agree that electrons have rest mass while photons do not. However, there is disagreement and uncertainty surrounding the mass of phonons and the implications of light behavior in different media. The discussion remains unresolved on several points, particularly regarding the interpretation of mass in various contexts.
Some participants express confusion over the definitions and implications of mass, particularly in relation to photons and phonons. There are references to various sources and articles, but no consensus is reached on the interpretations presented.
What does ##m_e## usually refer to?SSG-E said:
?berkeman said:
Copy/paste your thread title into a Google search. Then do some reading in the search results. That should answer the ##m_e## part. You will likely still have a few questions about the mass of a photon and phonon, so reply with links to your reading and ask *specific* questions about that reading so that we can help you. Thank you.SSG-E said:
It means electron rest mass. But an electron can't be at rest so how it has rest mass?berkeman said:
You are confusing electrons and photons. Can you post links to the reading you've been doing? That will help us to help you.SSG-E said:
I know the differences between electrons and photons. I just replied about the symbol 'me'. So the correction is: A photon can't be at rest so how it has rest mass? Is 0 considered mass?berkeman said:You are confusing electrons and photons. Can you post links to the reading you've been doing? That will help us to help you.
Where are you reading that?SSG-E said:
I have yet read at many websites and watched you tube videos.berkeman said:
Please post a link to such a source and highlight where they say a photon has rest mass...SSG-E said:
Electrons don't come at rest. Electron rest mass is the mass of an electron as measured when its speed is zero relative to an observer. A photon never comes at rest thus its rest mass is 0. But why can't be the rest mass of a photon be measured when its speed is zero relative to the observer?berkeman said:
Because photons move at velocity c (the speed of light) relative to all observers. They never appear at rest to any observers. There are probably some Insights articles that we can point you to. Back in a minute...SSG-E said:
Not always i.e. inside glass they are moving slower,and inside heavy water of a nuclear reactor very slow.berkeman said:
binis said:
You have right,might be inside the core,not in heavy water.Borek said:
binis said:
binis said:
A static EM field is practicaly not extending to infinite (math function has a definition field);how can EM waves do it,except viewing them as traveling particles? Moreover,you know that pair production is of one gamma-photon,not of a quantum EM field.weirdoguy said:
binis said:
binis said:
I'm not sure what you mean here, but I'm sure it won't help OP understand the concept of mass, so I don't think it's a good idea to continue that.binis said:
SSG-E said:
SSG-E said:
You can think of light moving through matter as photons slamming into atoms, being absorbed and then being emitted again, many times over. This process has the effect of slowing down the propagation of the wave as a whole but each individual photon still moves at c while being scattered from atom to atom, it's just that this whole process makes it take longer to get to the other side of the material.binis said:
Isn't this the fluorescent effect?AndreasC said:
binis said: