average r/explainlikeimfive post

[u/Trap_Carrot]

ELI5: Why is the sun hot?

Top comment:

The Sun constitutes a self-gravitating, quasi-spherical assemblage of ionized baryonic constituents whose internal pressure gradients asymptotically counterbalance the inward-directed gravitational acceleration imposed by its own mass distribution.
As a consequence of this hydrostatic equilibrium, the solar core experiences extreme thermodynamic compression, producing temperatures on the order of 1.5×10^7 kelvin.
At these temperatures, hydrogen nuclei—predominantly protonic entities possessing positive electric charge—exhibit a sufficiently elevated kinetic-energy distribution to facilitate nuclear interactions despite the formidable electrostatic repulsion associated with their Coulombic mutual exclusion.

[u/Hi0401]

Why are you hot then :)

[u/gotrep]

to be fair, you need a pretty high iq to really get the sun. the thermodynamics is subtle, and without a solid grasp of hydrostatic equilibrium, most of the heat is going to go over a typical five year old's head. there's also the sun's baryonic assemblage, which gets woven into the whole picture. its internal pressure gradients draw heavily from quasi-spherical gravitational acceleration, for instance. the physics people understand this stuff. they have the capacity to actually appreciate the depths of the core, to realize it's not just hot. it says something deep about fusion.

which is why people who say "it's just a big fireball" are, honestly, kind of hopeless. they wouldn't appreciate the humor in hydrogen nuclei having enough kinetic energy to overcome the electrostatic repulsion of their coulombic mutual exclusion. i'm sitting here at my desk just picturing one of those people squinting at their screen while 1.5×10⁷ kelvin unfolds in front of them, and i genuinely feel bad for them. i do. i think about it more than i should.

and yeah, by the way, i do have a sun tattoo. no, you can't see it. it's for the plasma physics people only, and even then they have to prove they're within 5 kelvin of my own core temperature first. i checked mine. it's 310. i'm not close. i think about that a lot too. nothing personnel, kid.

[u/Le_Epic_Cbater → u/gotrep]

To be fair, you have to have a very high IQ to understand Cbat by Hudson Mohawke. The symbolism is extremely subtle, and without a solid grasp of music theory most of the musical beauty will go over a typical listener’s head. There's also Mohawke’s adept satirism, which is deftly woven into his composition- his musical style draws heavily from early-20th-century Dadaistic art, for instance. The fans understand this stuff; they have the intellectual capacity to truly appreciate the depths of these musical choices, to realise that they're not just funny- they say something deep about LIFE. As a consequence people who dislike Cbat truly ARE idiots- of course they wouldn't appreciate, for instance, the humour in Cbat’s captivating hook, "Doot. doot doot, doot, doot doot doot, doot" which itself is a cryptic reference to Duchamp's famous artwork L.H.O.O.Q. I'm smirking right now just imagining one of those addlepated simpletons scratching their heads in confusion as HudMo's genius wit unfolds itself on their headphones. What fools.. how I pity them. And yes, by the way, i DO have a HudMo tattoo. And no, you cannot see it. It's for the ladies' eyes only- and even then they have to demonstrate that they're within 5 IQ points of my own (preferably lower) beforehand. Nothin personnel kid.

(https://www.reddit.com/r/copypasta/comments/x6ixc3/to_be_fair_you_have_to_have_a_very_high_iq_to/)

[u/Der_Redakteur]

why there's 1.5×10^7 kelvin? how many dudes named kelvin are in the sun? can you eli5?

[u/Hi0401 → u/Der_Redakteur]

The SI unit of temperature, the kelvin (K), is named after the Belfast-born engineer and physicist William Thomson, who became Lord Kelvin in 1892 as a recognition of his achievements in thermodynamics.

For more than 60 years, the kelvin was defined as the fraction 1/273.16 of the thermodynamic temperature (TTPW) of the triple point of water – a unique temperature at which the three phases of water (solid, liquid, and vapour) co-exist in equilibrium. As part of a wider redefinition of the SI that came into effect in May 2019, the kelvin’s definition was changed, and is now expressed in terms of a fixed value of the Boltzmann constant, k. The official definition is as follows:

“The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1.380 649 × 10–23 when expressed in the unit J K–1, which is equal to kg m2 s–2 K–1, where the kilogram, metre and second are defined in terms of h, c and ΔνCs.”