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Bah. The article doesn't appear to answer my long-standing question which is : where exactly do the photons come from? It says black bodies emit photons, but...

Bah. The article doesn't appear to answer my long-standing question which is : where exactly do the photons come from? It says black bodies emit photons, but...how exactly? It says maybe its emission spectrum photons which aren't black body radiation. I have a slightly better idea where those photons come from: an electron changes energy state in an atom and as a side-effect a photon is released. Still don't really know where the photon came from though..

dataflow 5y ago
IIRC (from high school chemistry?) electrons go into higher energy levels due to the release of chemical energy, then emit photons as they fall back to lower energy levels (the energy of the photon being the delta between the energy levels). Is that accurate/am I missing anything?
whatshisface 5y ago
Take an electron and shake it back and forth. Everything that feels its force will shake too. That's a photon.
- etrautmann 5y ago
  I had not quite thought about it in this way, thank you!
femto 5y ago
And if we get two photons above a certain energy and slam them together we get an electron and a positron. So where did they come from and where did the photons go? The electron emits a photon: photons from photons. And all those virtual photons that make the electron hang around near the the nucleus. It seems like its photons all the way down...
dbsmith83 5y ago
> It says black bodies emit photons, but...how exactly? When an object has any temperature above 0K, that means the chemically bonded particles are moving around/vibrating. This movement of charged particles (release of internal energy) creates electromagnetic radiation (photons). The other radiation you are talking about is also energy being released as photons, but it is from electrons in an excited state falling to a lower energy state. Molecules can take in energy differently. Some frequencies of incoming energy produce bond movement/vibrations, and other frequencies can excite an electron's state. Consequently, when the energy is released, it can be in different frequencies (infrared/heat, visible light, UV, etc.) depending on the amount of energy lost. Since electron orbitals are discrete states, the release of energy from an electron going to a lower orbital is a discrete frequency of light.

dataflow 5y ago

IIRC (from high school chemistry?) electrons go into higher energy levels due to the release of chemical energy, then emit photons as they fall back to lower energy levels (the energy of the photon being the delta between the energy levels). Is that accurate/am I missing anything?

whatshisface 5y ago

Take an electron and shake it back and forth. Everything that feels its force will shake too. That's a photon.

etrautmann 5y ago
I had not quite thought about it in this way, thank you!

femto 5y ago

And if we get two photons above a certain energy and slam them together we get an electron and a positron. So where did they come from and where did the photons go? The electron emits a photon: photons from photons. And all those virtual photons that make the electron hang around near the the nucleus. It seems like its photons all the way down...

dbsmith83 5y ago

> It says black bodies emit photons, but...how exactly? When an object has any temperature above 0K, that means the chemically bonded particles are moving around/vibrating. This movement of charged particles (release of internal energy) creates electromagnetic radiation (photons). The other radiation you are talking about is also energy being released as photons, but it is from electrons in an excited state falling to a lower energy state. Molecules can take in energy differently. Some frequencies of incoming energy produce bond movement/vibrations, and other frequencies can excite an electron's state. Consequently, when the energy is released, it can be in different frequencies (infrared/heat, visible light, UV, etc.) depending on the amount of energy lost. Since electron orbitals are discrete states, the release of energy from an electron going to a lower orbital is a discrete frequency of light.