Expert: Jayendra Upadhye - 1/25/2005

Question
I've read a few articles about scientists monitoring some white dwarf stars they are fairly certain have crystalized carbon and oxygen crusts.  The journalists loved writing about these diamond-stars, but I've been wondering, is the outer crystal lattice of the white dwarf--when it cools--dependent upon the immense gravity to maintain itself?  Would it ever be possible for a piece of that diamond to exist anywhere but the surface of the star?  I've read that the gravity produces of density of about 1 ton/cubic inch.  

What would happen to the "diamond" surface if the white dwarf star broke apart--say by a collision, or tidal forces?  Would any of the outer diamond shell remain?  Or would the lack of gravity cause the crystal structure to relax and explode, once there was nothing helping to contain the incredibly dense structure?

I know this is all theory, but I'm mulling over some ideas for a science fiction story and I find this concept of a large diamond fascinating.  Thanks for any help you can provide.

Answer
Hi,
Surely, Diamond material WILL exist on White dwarf stars PROVIDED, their surfaces have cooled enough to allow matter to exist in NON-IONISED solid form!

But then who would call them white?
By definitions, "WHITE" dwarf's are calles such becasue their surface temperatures are very very high! At those temperatures, we have only degenerate matter / plasma somehow held in the grip of the crushing gravity.

Over time, these dwarf stars become cooler brown dwarfs, and add to the "dark matter" that scientists are screaming about!
[We have sizable population of these old guys who have now gone infra-red! and they are massive indeed!]
You could even have alien civilisations somehow thriving on the surfaces of these immense giants, that remain perpetually warm! And their "vast inner energies" can be tapped too..provided our aliens can stand the gravity!

Coming to your question, once cooled, the carbon layers deep down, -- below the liquid oceans of oxides of gases, and nitrogen and methane etc, (yes there would be convective sedimentation as in the case of the earth, on the dwarf too! Laws of physics apply every where the same, -- would be indeed diamond!

Fear not! Once formed diamonds DO NOT EXPLODE! After all our earthly diamonds too formed deep down in volcanic vents, at very high pressures! DO THEY EVER EXPLODE just because they are "up" in the open air?

Carbon-carbon bonds are quite strong in the lattice structure of diamonds!
Read some crystallography if you can lay hands on it in the local library.

Jayen