Submitted by MistWeaver80 t3_yp8a4b in science
Reply to comment by [deleted] in Bizarre star may have a solid surface, according to X-ray observations. Astronomers have now spotted a super strange one that seems to have a solid surface. Its intense magnetic field is strong enough to overcome its blistering temperatures and “freeze” its outer layers into a solid crust. by MistWeaver80
It's black body radiation, usually taught in stat mech classes when deriving the Planck distribution (distribution of energies in a gas of photons). It's low level mechanism comes from what are called "continuum" interactions. They are called that because they produce a continuous spectrum unlike atomic interaction which are discrete.
Some examples of continuum interactions include Thomson/Compton scattering (photons bouncing off electrons, Thomson scattering is the low energy approximation and Compton is the relativistic case), Bremsstrahlung radiation (electrons scattering off ions), photoionization (electrons being kicked out of their atoms), collisional interactions (atoms and ions bumping into eachother), and autoionization (atoms with multiple excited electrons reconfiguring to shoot off an outer most electron through quantum tunneling). For those for who it's not clear where exactly the light comes from in all of these, accelerating charged particles emit light.
All of these interactions together create the Black-body (or Planck) distribution.
Source: I'm one of the developers of an astrophysical radiative transfer code
Space is so tight
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Thats exceptionally cool.
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Does the black body spectrum change for a neutron star, given there are significantly less electrons and protons than in normal matter?
It's spectrum is much more complicated because it's very high energy and you need to consider how the light interests with the protons and the structure of the magnetic fields.
I'm not an astrophysicist, but are you saying electrons are moving so fast they generate light? Isn't light a photon? Where are they coming from?
According to Maxwell's equations, a changing electric field creates a magnetic field, and a changing magnetic field creates an electric field. If you set this up as a set of differential equations you get perpendicular propagating waves in the electric and magnetic fields.
A charged particle moving at a constant speed makes a constant magnetic field. An accelerating charge makes a changing magnetic field which makes a changing electric field etc. which makes an electromagnet wave. The quantization of this field results in the waves propagating as photons.
But where do the photons come from?
From the electromagnetic field
They just poof into existence? I'm assuming I just don't understand what a photon actually is.
Think of a photon as similar to a musical note when you play an instrument. For a string instrument, you pluck the string and it causes it to vibrate at a specific frequency depending on the length (i.e. it's boundary conditions). This is kind of like a photon but instead of plucking a string you are "plucking" the electromagnetic field and it makes a vibration at a certain frequency depending on the boundary conditions (electrons, ions, etc) of the system.
I understand sound to be the consecutive vibration of atoms which is why sound cannot traverse a vacuum. For light to traverse space is my understanding that is that photos are some kind of discrete particle with mass and that's why things like solar sails work.
From what you're saying, the interaction of the fields creates photons. Is this energy converting into matter and the genesis of a discrete particle?
Photons do not have mass. They do carry momentum though.
Man I feel dumb. What is a photon made of then? It's just energy that flows and glows until it dissipates? Thanks for humoring my ignorance!
Photons are made of photons. They are fundamental particles
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