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Comment by JKCalhoun | Hacker News Reader

I wonder why we can't model the sun. It would seem to be simpler than say modeling the weather on Earth.

https://en.wikipedia.org/wiki/Magnetohydrodynamics

Sure we do. It is different and no simpler than modeling weather. Weather at least has the advantage of a 3D system decomposing into a 2D sphere X 1D height dimension via a thin shell approximation, but also has the complexity of humidity. The Sun is intrinsically a 3D system, but has electromagnetic complications.

> the complexity of humidity

Without the nonlinearity of water vapor<=>liquid<=>ice, Earth weather predictions would be pretty darn easy.

IANA astrophysicist, but I'm guessing the same would be true about the Sun without magnetic fields.

1. The sun has a (weak) magnetic field that affects how its gas moves, which we don't fully understand. 2. There is a Coriolis force all the way down to the center of the sun, which makes the gas move in weird ways. 3. As a sphere of fluid, the sun supports vibrational modes that we are only just beginning to understand. (See work by e.g., Conny Aerts) 4. We can't really see into the sun’s interior, although understanding the vibrational modes will help.

Anecdotally, Argentina tried it[0]. The project was sold to Peron as way to create artificial suns.

0:https://en.wikipedia.org/wiki/Huemul_Project

What does “model” even mean here?

make the sun into a set of mathematical equations, like the way gargantuan was modeled in interstellar https://github.com/sirxemic/Interstellar or the way schrodinger wave equations model an atom. [libretexts schrodinger equation] https://chem.libretexts.org/Courses/University_of_California...

My question still stands? _What_ aspect are you modeling exactly? The Sun as a celestial body? The fluid dynamics of the surface? The nuclear process going on in the core?

You can’t just entirely “model” something as complex as a star anymore than you can do large scale simulations of the universe at the atomic level. If we could we would be much more ahead as a civilization.

Why would it be simple?

No butterflies.

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