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Thread: Question about a very big number (# of photon interactions w/ particles)

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    Question about a very big number (# of photon interactions w/ particles)

    I was watching some youtube videos about the Bee movie, where you watch the bee movie but every time there's a bee you watch the entire ice age pentology but every time there's a syllable spoken you watch the entire toy story trilogy but every time the color green is in a frame you watch every video every uploaded on youtube but every 10 seconds you watch the every episode of the simpsons. it ended up being 4.2*10^35 seconds. This got me thinking about big numbers in general...I know shuffling a deck of cards can yield a possible 52! different combinations, but what would be the number if you calculated approximately how many times any photon has interacted with a particle in the history of the observable universe up until this point?

    I'm sure you could calculate photons per second coming out of a star, average photon bounces per second inside of a star, length of time each photon stays in a star, and multiply it out based on # of stars in the known universe, but i have no clue where i'd start. I asked this on Reddit /r/theydidthemath and someone told me it was impossible but using the simple (albeit huge) numbers i provided in the start of this paragraph, i don't think it'd be impossible to do a rough estimate.

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    Here is a NASA link that estimates the number of interactions in the Sun.
    https://image.gsfc.nasa.gov/poetry/ask/a11354.html
    That is some 5 x 1021 for each photon emitted from the photosphere, of which I estimate about 1045 per second. Those interactions occurred over a period of roughly a million years. With some 100 billion stars in our galaxy and billions of galaxies in the known universe, there are mind-blowing gazillions of interactions.

    It should be noted that an increment of energy consisting of one gamma photon generated by a fusion event in the core is transformed into thousands of visible light photons at the photosphere. It cannot be just one photon bouncing around and eventually reaching the photosphere, if I am not mistaken.

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    Quote Originally Posted by Hornblower View Post
    It should be noted that an increment of energy consisting of one gamma photon generated by a fusion event in the core is transformed into thousands of visible light photons at the photosphere. It cannot be just one photon bouncing around and eventually reaching the photosphere, if I am not mistaken.
    I donít think it becomes thousands of photons. I think what happens is that each photon is absorbed and then emitted (as a new photon,, so the number never increases.


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    Quote Originally Posted by Jens View Post
    I don’t think it becomes thousands of photons. I think what happens is that each photon is absorbed and then emitted (as a new photon,, so the number never increases.


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    If the number of photons per second leaving the surface is equal to the number per second generated in the core, the energy being radiated at the greatly reduced effective temperature would be way down, which it is not. I stand by my statement.

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    Surely the fusion reaction makes high energy neutrons, (or one per fusion i should say), and those neutrons carry energy into further reactions making photons for final radiation. So there is a photon multiplier effect.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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    Quote Originally Posted by profloater View Post
    Surely the fusion reaction makes high energy neutrons, (or one per fusion i should say), and those neutrons carry energy into further reactions making photons for final radiation. So there is a photon multiplier effect.
    We don't need anything fancy in further reactions. As I see it, we can have a particle take up some energy from a high-energy photon and subsequently emit it in two or more stages in the form of two or more lower-energy photons. Whatever the action is, we have the interior of the star thermalized at any given location, with the temperature dropping as we approach the photosphere. At or near the core we have a preponderance of gamma photons, while near the photosphere we have a preponderance of visible light photons. To keep the total energy flow equal at all radial positions we need to have more photons in the outer regions.

    If I am missing something here, I will welcome well-thought-out, convincing explanations.
    Last edited by Hornblower; 2019-Oct-07 at 04:32 PM. Reason: fix a misspelling

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    Quote Originally Posted by Hornblower View Post
    If the number of photons per second leaving the surface is equal to the number per second generated in the core, the energy being radiated at the greatly reduced effective temperature would be way down, which it is not. I stand by my statement.
    Sorry, I think I was wrong in my response. Thinking about it, I guess it would create extra protons because of the energy.
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