Journal freality's Journal: Metallic sun 1
I'm posting this for follow-up commentary from @APODNereid, since the thread is now closed.
http://slashdot.org/comments.pl?sid=2967801&cid=40758811
You ask what would keep the surface metallic. Thinking about this more, I found a couple of facts:
The Sun's surface has an energy flux density ~30x that of a hot metal rod at 3,000 C (around the glow point for tungsten in a lightbulb) in the experiment described here:
http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Temperature_of_the_Sun
Which is hot indeed, and would surely evaporate the tungsten here on Earth.
However, the Sun also has 28 times greater surface gravity than that on the surface of the Earth (28x the surface gravity, so linearly greater pressure for the same area too):
http://en.wikipedia.org/wiki/Sun (see sidebar for surface gravity)
The core of the Earth is thought to be about as hot as the surface of the Sun, and yet still a solid metal ball:
http://en.wikipedia.org/wiki/Inner_core
What explains the core not evaporating into a gas or plasma? The pressure is very high.
A 1% depth crust on the SUn (similar to the Earth's proportion) would be roughly the diameter of the Earth, so the amount of material involved is at least equally astronomical
(also, whether or not it's metallic per se is beyond me; the more interesting point vis-a-vis the original article is whether the surface is solid.)
Thoughts?
Metallic hydrogen (Score:2)
Here's an interesting article:
http://en.wikipedia.org/wiki/Metallic_hydrogen#Metallization_of_hydrogen_in_shock-wave_compression [wikipedia.org]
Especially the discussion of the LLNL shock-wave compression. Metallic indeed :)
3000K is not too far from the temperature of the surface of the Sun, and the pressures are thought to vary from virtually nothing at the surface to Peta-pascals in the core, so somewhere there's a transition by the 140GPa needed for metallization. Whether this is within the convective l