Uranus and Neptune May Have "Oceans of Diamonds"

Third Position writes "Oceans of liquid diamond topped with solid 'icebergs' of the precious gems could be on Uranus and Neptune. The first-ever detailed research into the melting point of diamond found it behaves like water during melting and freezing — with its solid form floating on the liquid. A large diamond ocean on one or both of the planets could provide an explanation for an oddity they both share: unlike Earth, they do not have magnetic poles that match up with their geographical poles." The article doesn't mention what the pressures might be like in these outer-planets environments, but the researchers found that liquefying diamond requires 40 million times Earth's atmospheric pressure at sea level.

Comments

Finally

[langelgjm]

So now /.ers can tell their "girlfriends" that if you want a diamond, you're free to look for one in Uranus?

Re:Finally

[theMoleofProduction]

So now /.ers can tell their "girlfriends" that if you want a diamond, you're free to look for one in Uranus?

Worth a shot...
"Hey, baby! Answer me this: What's the hardest thing known to man, and you can find lots of it way up in Uranus?"

*oof* ...and now I have a black eye to explain to my boss. Damn you, science!

For the dull knives in the drawer

[TheRealMindChild]

detailed research into the melting point of diamond found it behaves like water during melting and freezing -- with its solid form floating on the liquid

I only point this out because you would be surprised at how many human beings don't know this, but for it to float to the top, that means its frozen state is less dense, hence expands, when freezes. Almost nothing else does this.

Re:For the dull knives in the drawer

[wizardforce]

Bismuth, Silicon, Germanium and Gallium are all elements that have a solid phase that is less dense than their liquid phase. Acetic acid I hear is less dense in its solid phase but I haven't had a chance to verify this.

Re:For the dull knives in the drawer

[Artifakt]

Darkroom photography verifies this. 'Glacial' Acetic Acid is used in developing and fixing photographic film, and particularly silver halide based prints. Normally, it is kept heavily refrigerated between uses to slow evaporation and keep it at the right concentration, and it not infrequently gets cold enough for bits to solidify and float on top. Home photographers, who often left bottles sitting in their darkroom fridge for months, tended to notice sizeable bits more than pros who went through whole bottles in days, and it was some of these amateurs who tried thawing out just the frozen bits, and by proving they worked at the same speed in film processing, showed they were at least roughly the same concentration as the liquid chemical, and were not acetic acid depleted, near pure water ices.
    Of course, now that practically nobody actually develops film anymore, what was once well known chemistry for amateur hobbyists becomes unverified rumor to a new generation.

Re:For the dull knives in the drawer

[reverseengineer]

My guess is that the difference in density may be strongly dependent on the pressure. At standard conditions, diamond is actually the densest form of pure carbon, and at atmospheric pressure, carbon sublimates instead of melting. It seems possible to me that liquid diamond is more compressible than solid diamond, such that the liquid density is more variable than the solid density with respect to pressure. Under a relatively low applied pressure (well, still gigapascals), diamondbergs would sink. At some phenomenal pressure, the densities would match and solid would be neutrally buoyant in liquid. Above that pressure, the atoms in liquid diamond would be more crushed together than those in the diamond lattice, and the crystal would float. The inherent strength of the cage-like solid diamond structure makes it energetically favorable, despite the atoms being farther apart.

Much as I'd love to make a great pun about uranus.

[cmowire]

The possibilities of exploring the outer "ice giants" is massive. I think, at least. I may not even make the pun because I think the idea of exploring them is so interesting.

Submarines are designed to handle a test depth of maybe 1600 ft which means maybe 50 bar of pressure. At that pressure, the atmosphere of Uranus is a little below freezing. The gravity is less than Earth. I suspect that with correct ballasting you could make a metal sphere float in the atmosphere for quite some time by keeping the insides pressurized to a convenient atmospheric pressure. So sticking around for a while isn't hard.

I can't find any good information on the radiation environment there and if you could put humans in the little bubble circling Uranus.. um.. yeah, I lied above.

Good riddance

[langelgjm]

Might be worth the cost of shipping if it did away with the diamond industry once and for all! Of course, what with marketing, De Beers would probably buy up the stock from Uranus and either dump it in the ocean, or sell it at 500% the price of normal diamonds as "space diamonds... the most romantic diamond yet. Shit that's been floating on the seas of Uranus for millions of years can now be on your hand - FOREVER."

pressure off by a magnitude

[wizardforce]

40 million atmospheres is the kind of pressure that you'd measure under 400 million meters (400,000km) of material at a density of 1 g/cm^3 at a constant 1 g. Uranus and Neptune's gravity field is near 1g give or take and the density is not much more than 1g/cm^3 so the pressure in the core can not be 40 million atmospheres as there isn't ~400,000 km of material sitting above the core. Given that Uranus has a radius of ~25,000 km, density of ~1.27 g/cm^3, surface gravity of 8.7 m/s^2 and that the gravity field drops off roughly linearly with depth, the pressure is probably about a tenth of what TFA says diamond started to melt. Either someone dropped a zero where it didn't belong or Diamond isn't fluid in these planets' cores.

Re:Actually "Oceans of melted coal"

[wizardforce]

Normally when you try to melt a Diamond, the Diamond converts to graphite first and then melts. When the material freezes again, it isn't Diamond anymore. In the case of the article, the Diamond is under so much pressure that it no longer converts to Graphite before melting. When the liquid freezes again, it isn't Coal but Diamond.

It's a wonderful planet

[dangitman]

That's nothing. I know of a planet that is made out of candy and chocolate and ponies. Just step into my vehicle, and I'll show it to you, little girl.

What's Unlike Like?

[DynaSoar]

"...unlike Earth, they do not have magnetic poles that match up with their geographical poles."

Unlike Earth, neither does Earth. The Earth's south magnetic pole is presently about 25.6 degrees from the south pole. Granted, that's not 60 degrees, but apparently neither are theirs since according to TFA the magnetic poles on Uranus and Neptune "can be up to 60 degrees off the north-south axis", it they were, there's be no reason to say "can be".

There's no note regarding secondary poles on the giant planets like on the sun, but according the Oersted and Magsat satellite data and article in Nature in 2002 (416/8661, pp 620-623) there's an alternate pole developing in the South Atlantic west of South Africa. There's also a geomagnetic anomaly near Lake Baikal in Siberia that causes deflection in the magnetic field measured as far away as Japan, but there's no evidence (or none as yet) that it's a developing "alternate". But one's enough, when it comes to picking apart TFA. Not only is Earth unlike the Earth they compare against while constructing their theory, it's quite capable of being equal to the giants in its unlikeness in the complete absence of diamond seas with or without diamondbergs.

Re:Well, that's one way to get the space race movi

[Famanoran]

But then you'd miss out on all the fun of mining it out of the Earth...