• mojofrododojo@lemmy.world
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    7 hours ago

    it can take tens of thousands of years bouncing around inside the sun before they exit too. always thought that was pretty neat.

    • portuga@lemmy.world
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      6 hours ago

      Or just eat them by night. It’s pretty hard to escape those thousand year photons specifically targeting OP’s icecream by day

  • GooberEar@lemmy.wtf
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    14 hours ago

    From the perspective of the photon, this all happens more or less instantaneously. Or so I have been told. I was also told that my tongue has 5 or 6 zones where different aspects of flavor are detected and I now know that to be wrong. So maybe fuck your ice cream.

    • psud@aussie.zone
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      54 minutes ago

      more or less instantaneously

      That’s relativity. The faster a thing goes the slower time runs for them. Photons are travelling at light speed and so they don’t experience time at all

    • portuga@lemmy.world
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      6 hours ago

      Now you got me curious about photons, I mean what is wrong with your tongue? Thoughts and prayers

  • Eheran@lemmy.world
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    15 hours ago

    It is not direct sunlight that is melting your ice mate. Let’s say the scoop has 10 cm² getting blasted from the sun, that’s 1 Watt of heat under maximum possible conditions (Sun vertically above you, perfectly black ice, etc.). tl;dr: In total from convenction 1.8 W, condensation 2.5 W and radiation 0.65 W = 4.95 W -> maximum possible sunlight on earth would only increase this by 20 %, more realistic sunlight something like 10 %.

    Actual math: Compare that to ambient temperatures of say, 30 °C, and let’s again say 10 cm² cross section, which translates to a diameter of 3.57 cm, so a sphere with a surface of 40 cm². The heat transfer coefficient under normal conditions is about 15 W/(m²K), so we get: 15 W/(m²K) * 0.004 m² * 30 K = 1.8 W

    Additionally, we have latent heat from water (humidity) condensing on the cold surface: Let’s assume a Schmidt number of 0.6, so we get a mass transfer coefficient of: 15 W/(m²K) / [1.2 kg/m³ * 1000 J/(kgK)] * 0.6^(-2/3) = 0.0176 m/s Specific gas constant: 8.314 J/(molK) / 0.018 kg/mol = 462 J/(kgK) So the mass flux (condensation speed) is: 0.0176 m/s * 2000 Pa / [462 J/(kgK) * 273 K] = 0.00038 kg/(m²s)

    Given the heat of condensation of 2257 kJ/kg water we thus get: 0.00038 kg/(m²*s) * 2257000 J/kg = 632 W/m²

    And thus for our little sphere: 632 W/m² * 0.004 m² = 2.5 W

    … Then we also have radiation from the hot surrounding, let’s assume 30 °C again, we get: Q = 5.67E-8 W/(m²*K^4) * 0.004 m² * (303 K^4 - 273 K^4) = 0.65 W (omitting radiation from the sky)

    • JohnDClay@sh.itjust.works
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      9 hours ago

      So made this meme is eating ice cream when it’s below or near freezing? Because you still get ice melting below freezing due to radiation.

      • Eheran@lemmy.world
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        10 minutes ago

        Yes, while the radiation puts more energy in than the convective etc. cooling removes. So near 0 this is guaranteed, since the temperature difference from ice to ambient is almost 0 while radiation keeps pumping in something like 0.5 W. But who eats ice at freezing temperatures… And outside?

  • ryedaft@sh.itjust.works
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    17 hours ago

    Photons don’t gather energy and they definitely don’t move slowly through the sun.

    • Artyom@lemm.ee
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      16 hours ago
      1. They’re traveling in a medium, so they move slower than in space
      2. Due to the random walk caused by multiple scattering, it can take millions of years for a photon to escape the sun after bring produced in the core.

      You are right that they don’t gather energy, but they do multiply. What would be a single high energy x ray in the core will eventually downscatter into an army of optical photons.

    • take6056@feddit.nl
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      17 hours ago

      For photons, their moving relatively slow from the inside to the outside of the sun. Although, I think, it’s technically a bunch of photons bumping each other into existence.

    • Nougat@fedia.io
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      17 hours ago

      … they definitely don’t move slowly through the sun.

      They kind of do. While the photons inside the Sun move at a very high speed, they can take up to about 170,000 years to get from the middle of the Sun to the outside, because they change directions a lot on the way.

  • expatriado@lemmy.world
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    16 hours ago

    photons are generated at the core from matter by hydrogen fusion (bigger elements later in the star life), the photons travel to the surface by absorption and re-emission taking about 100,000 years in average to escape, despite traveling at the speed of light. so the slow part depends on perspective

    • I_Has_A_Hat@lemmy.world
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      17 hours ago

      And from the proton’s perspective, it is created and arrives at its ultimate destination instantly.

      • SnowmenMelt@lemmy.world
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        15 hours ago

        Thinking about a photon’s perspective is nonsensical. You are asking for a frame of reference where the photon is at rest but the very definition of a frame of reference in relativity is one where photon’s are travelling at the speed of light. Therefore there cannot be a frame of refernece where a photon is at rest and so a photon can never have a perspective, and neither can anything travelling at the speed of light.

      • henfredemars@infosec.pub
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        16 hours ago

        One has to imagine whether their life is satisfying provided it contains no journey whatsoever. Only destination.

        • expatriado@lemmy.world
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          16 hours ago

          ackchyually… the destination happens countless times before it leaves the surface of the sun

  • don@lemm.ee
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    17 hours ago

    “It took me a hundred thousand years to escape the prison of a motherfucking star, and you have the gall to complain about your little ice cream cone melting?!

    Fuck you.”

    Me: well when you put it like that

    • TriflingToad@sh.itjust.works
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      16 hours ago

      “to land in your Nintendo 64 and to give you the world record”
      *last frame is them celebrating together with matching Mario shirts*