[extropy-chat] will the sun rise?

[Reason]

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org
> [mailto:extropy-chat-bounces at lists.extropy.org]On Behalf Of Amara Graps

> Eugen Leitl:
> >Sun is harder because if you trap the radiation it will heat up
> >and bloat up and simultaneously reduce the fusion rate. Perhaps
> >you can blow off chunks of photosphere, by periodic/asymmetric
> >feedback of the solar output.
>
> >I don't see how this is a controlled disassembly process, though.
> >Ditto Jupiter.
>
> It seems to me that the convection process (usually assumed in
> the outer layers of a main sequence star) for transporting energy
> would make star-lifting very hard to control.

I wrote and maintained stellar modelling code a decade ago; pretty standard
Henyey iterative stuff that could be used to generate a model of star B when
starting from star A provided they weren't too different. This was used to
model the evolution of a star by tweaking metallicities in successive models
to reflect increasing age. One of the items I recall being a problem was
hacking in a way of adding mass loss through stellar wind; this was very
significant to the overall evolution in Pop III stars.

The onion layering in the model was done in such a way as to try and keep
the delta between variables in adjacent layers as low as possible. This
meant that half of the onion layers in the model were in the very outer
layers, where variables change greatly over a very small fraction of the
stellar radius. Any radical changes to the outer layers caused great
instability in the model, and finding a solution that both kept it happy and
was justifiable in terms of the physics was quite hard.

The other problem was core ignition events - about half of the evolutionary
sequences couldn't be convinced to iterate past that point, and getting the
thing past the first core ignition was a real art.

Reason
Founder, Longevity Meme