>Electron gets excited, likely through atom/atom collision, either through literal collision in a gas or vibrations in a solid.
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>Electron comes back down and emits a photon

You can have thermal emission only from point charged particle, you don't need electron levels, no? I don't have experience with solids, but this was my understanding, that it is proportional to the distirbution of velocities of atoms in the object, much like the free-free emission is a continuous spectrum too. I understand that different objects have different emissivities, and that emission at different wavelengths is different, but why would that be the case outside electron transitions? Could a possible crystalline lattice play an effect in this, restricting movements of individual atoms?

Many rock types are fundamentally the same -- basalt on the Moon, Earth. Venus, and Mars is all pyroxene, olivine, and plagioclase feldspar. It weathers into different minerals depending on the environmental conditions, so Martian sand is going to be different from Earth sand (unless you pick a weird place on Earth) in some subtle ways, but it's ultimately a pile of little pieces of the same minerals, just with some textural differences and maybe different trace minerals mixed with it.

Earth also has a lot of life and water. You won't find soil in any recognizable form except here. That's a mix of rotting plant matter and what we call regolith, or the powder to gravel sized pulverized rock that all solid planets have some form of at the surface.

So, you'd encounter familiar minerals and rocks making up texturally odd usually super dry sediments in weird contexts, to summarize.

It's true! Googling spectral emissivity may give you extra info.

Thermal radiation (both in gases and solids!) can be extremely simplified to

1. Electron gets excited, likely through atom/atom collision, either through literal collision in a gas or vibrations in a solid.
2. Electron comes back down and emits a photon

If your material has a nice continuous energy band (something that doesn't happen in gases, but happens in metal), the electron can get excited and unexcited without many restrictions, so you get a plank type distribution. If the electron is restricted to belong to certain bands (like in gases and some solids) emission will have to be restricted to those bands.

In bulk materials with large optical density (such as solids) you have to account for reabsorption, which happens preferentially at the emission frequencies, and the fact that your system is out of equilibrium starts to matter a lot. You get a mess instead of clean bands, but you don't get black body either!

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The temperature does vary, but less than temps do just going from one part of Mercury to another.

1. Mercury has no appreciable atmosphere. This means the temperature rises and falls very quickly in response to changing light levels/solar energy.

2. Mercury rotates very slowly (59 days), so that heating remains extremely uneven.

So, on the dark side, it's actually probably close to the same exact temperature no matter where the planet is in its orbit. On the light side, it might be tens or more of degrees warmer when it's closer to the sun, but there's no global 'climate' to shift, if that makes sense?

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It's a good short hand for describing what happens to matter at the event horizon without getting too graphic. I don't believe most objects would actually get stretched out — they'd probably be torn apart before then.

Essentially, due to the strong tidal forces, an object will either become stretched out or break out into a vertical line of debris. Depending on what the material is would change the exact nature (ex. a star may get stretched out as it is gaseous, but an astronaut would probably fall apart. Neither is very pleasant though)

Still I bed and don't have my glasses on yet, so I'm going to have to punt those requests to others.

The blackbody radiation is indeed choppy from solids, just with so much noise that it appears mostly continuous when measuring the spectra from sufficiently geometrically complex surfaces.

The problem is the wiki article alludes that this line emission from atoms breaking off from the material and having chemical reactions in the flames around it is not entirely responsible for enhancing its glow.

edit: idk why i considered gases (which i thought i know) and solids (which i know i don't know) as so different. Kirchoffs law applies to solids too, so if a solid is a poor absorber at a wavelength, it must be a good emitter.

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>A true perfect blackbody emits EVERY energy of photon along the curve, real matter in our universe can only do it at discrete energy levels on the curve

The energy levels of individual atoms have little to do with black body emission, no? You mean to tell me that the black body spectrum of real objects is choppy? Isn't the planck spectrum the result of taking into consideration the quantum nature of light, i.e. as discrete oscillators? Can you please give me a link where these steps arising from thermal velocities are observed and their mathematical description please? Also, keep in mind we are talking about solids here, not gases or plasmas.

The problem is the wiki article alludes that line emission from atoms breaking off from the material and having chemical reactions in the flames around it is not entirely responsible for enhancing its glow.

The answer is in the link you provided, and is alluded to by u/SirHerald. Black body radiation is the idealized emissions due to heat from a "black body." Any specific material will have a different actual emission spectrum when heated, depending on the difference in electron shell energy levels of its atoms or molecules. The energy levels that the electrons fall from in heated Thorium tend to release more photons that are in the visible spectrum of humans that the idealized black body radiation at the given temperature would.

Real atoms have individual electrons at specific energy levels. A true perfect blackbody emits EVERY energy of photon along the curve, real matter in our universe can only do it at discrete energy levels on the curve. Some elements have bigger 'steps' between certain parts of the spectrum. Thorium collects and then reemits a lot of visible photons, other elements have spikes in the IR or UV range, some have only very small divergence from a blackbody Planck curve. The elements which make 'extra' visible light are inherently superior things to heat up to make light as a result.

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Nevermind, found the correct answer: glow is due to oxides and chemical reactions AROUND the solid block of metal. However, the wiki article lists this effect as distinct from the black body spectrum of the object, and leaves the impression that even without it, the solid metal would glow more than a black body at those temperatures.

"Candoluminescence is the light given off by certain materials at elevated temperatures (usually when exposed to a flame) that has an intensity at some wavelengths which can, through chemical action in flames, be higher than the blackbody emission expected from incandescence at the same temperature.[1] The phenomenon is notable in certain transition-metal and rare-earth oxide materials (ceramics) such as zinc oxide, cerium(IV) oxide and thorium dioxide."

Whereas the wiki article for thorium says:

"A mantle glows brightly in the visible spectrum while emitting little infrared radiation. The rare-earth oxides (cerium) and actinide (thorium) in the mantle have a low emissivity in the infrared (in comparison with an ideal black body) but have high emissivity in the visible spectrum. **There is also some evidence** that the emission is enhanced by candoluminescence, the emission of light from the combustion products before they reach thermal equilibrium."

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No it's not combustion without oxygen. Spectral line emission usually originates from diffuse gases and plasmas, which exist also in flames, i.e. combustion, but not from solids. It is in the gas form that an atom can be excited, and then deexcite by emission of a photon, with little collisions happening while in the excited state. A solid block of metal (or other material) has a continuous spectrum, resulting from the velocity distribution of atoms in its composition, which usually resembles the Planck profile. Gases (plasmas!) also have a continuous spectrum, but that's a different story. If it was like the other poster said, a hot rod made of copper would glow blue when heated, while in reality the glow color depends on temperature of the rod.

Why does a solid block of thorium, when heated, emit more in the visible spectrum than in the infrared when compared to a black body of the same temperature? Is this claim even accurate?

Nevermind, found the correct answer: glow is due to oxides and chemical reactions AROUND the solid block of metal. However, the wiki article lists this effect as distinct from the black body spectrum of the object, and leaves the impression that even without it, the solid metal would glow more than a black body at those temperatures.
"Candoluminescence is the light given off by certain materials at elevated temperatures (usually when exposed to a flame) that has an intensity at some wavelengths which can, through chemical action in flames, be higher than the blackbody emission expected from incandescence at the same temperature.[1] The phenomenon is notable in certain transition-metal and rare-earth oxide materials (ceramics) such as zinc oxide, cerium(IV) oxide and thorium dioxide."

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You seem to be thinking of "the genetic mutation" as something separate from the cancerous cells. It's not.

That is, the genetic mutation that causes cancer isn't something that's expressed in your whole body that makes cancerous cells, it's something that happens in one cell that then divides uncontrollably (if the immune system doesn't eliminate is as foreign soon enough).

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What do you think incandescence is? It's essentially combustion without the oxygen, so the filament has to emit photons rather than undergo a chemical reaction. The spectral lines are essentially the same