Photons don’t gather energy and they definitely don’t move slowly through the sun.
- They’re traveling in a medium, so they move slower than in space
- Due to the random walk caused by multiple scattering, it can take millions of years for a photon to escape the sun after being 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.
It can definitely take millions of years for photons to leave a star due to dense protons causing collisions.
https://futurism.com/photons-million-year-journey-center-sun
I get what you’re saying but taking a long time is not the same as moving slowly
Slowly making their way does not equal moving slowly. It describes the time it takes to exit the sun, not the speed of the particle.
They’re also rapidly making their way and taking a long time.
And cold wind is when slow-moving air hits you at a fast speed.
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.
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
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
Just eat your ice cream before it melts. Glad i could help.
Or just eat them by night. It’s pretty hard to escape those thousand year photons specifically targeting OP’s icecream by day
it can take tens of thousands of years bouncing around inside the sun before they exit too. always thought that was pretty neat.
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)
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.
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?
I have eaten ice cream outside when temperatures were sub-zero Fahrenheit. It’s not something I do regularly but it’s happened and will probably happen again.
If I want ice cream, then I want ice cream. No other considerations matter.
Alright then. But at 0 °F it is not going to melt without your intervention, no matter how sunny it is.
Absolutely, I don’t disagree with that.
I was just sharing my anecdote as a counterpoint to your minor rhetorical point at the end, because at least to me, it’s funny since eating ice cream outside at -10 degrees is a ridiculous thing to do.
Though, I will note that while ice cream won’t melt at those temperatures, at atmospheric pressure it will still sublimate. So, in that way you could still lose your ice cream without intervention, it would just take a while.
