Well, I think SCR is right; it can only exist at extremely high pressures, and it then behaves like a group I metal. Incidentally, hydrogen is not considered a noble gas, as it is extremely reactive. It is explosive in air at almost any concentration.

Could someone please tell me what “Liquid Metallic Hydrogen” would look/feel like if you could hold some in a cup? Would it look/act like mercury? I simply cant visualise something I know of as a noble gas being a metallic liquid…”

It wouldn’t stay liquid metallic Hydrogen (lm-H) for long in a cup at room temperature and pressures that’s for sure!

It exists deep beneath the clouds in Jupiter becauseof that planets immense gravityand conseq2uent extremely high pressures. My understanding is its electro-magnetically conducting hence generating tehradiowaves and magnetosphere of Jove which is pretty colossal.

Maybe they’ve been able to make some in a lab somewhere … I’m not sure. But pour it into a cup and it’ll most likely flash back to gaseous state striaghtaway. Possibly taking you with it in a big BOOM!

Don’t now if that helps much but …

The internal structure of Jupiter is still mysterious – we have a number of different theories about it and it appears its core is paradoxically much smaller than that of Saturn and the other gas giants – saw a diagram in anastronomy mag once depicting this.

Read that one theory is that its the size of Earth and probably molten by the intense central heat , but squashed spherical by the pressure. Another theory suggest the carbonaceous asteroids and cometary material common in the region it formed may imply itcould be tarry, carbon-rich, relatively small object or even as Arthur C. Clarke sugested in the ‘Space Odyssey’ series composed of diamond.

Whatever the Jovian core is I gather it’ll be a very, very, v-e-r-y, looo-ong time before we can find out for sure! (Theories are well & good but I can’t see us visiting it … or getting much evdence conclusively on its composition other ways.)

Triton too, Kullat Nunu, has volcanic activity – geyers erupting .. well I think its nitrogen or methane – cyrovulcanism of a weird variety anyhow. They’e spotted a whole lot of dark streaks and I think also some of the actual plumes.

What Triton can do I think Pluto-Charon can do as well -now okay Pluto’s not a moon but Charon is – although if you want to get really picky and call it a double-planet .. okay, double dwarf planet .. Anyay, Ithinkwe’ll find a few other moons (Dione, Iapetus around Saturn for instance) show signs of geologicc activityinvolving resurfacing by flowing material – whether you term them volcanic or not .. is up to you!

Moreover, our our Moon was very volcanic at one stage – all those flat dark areas (mare or “seas”) were once seas of molten lava. So that’s another one … Whats that then :

1) Io
2) Enceladus
3) Triton
4) Luna (our Moon -at least in the past and perhaps even today if TLP are really related to volcanic activity there.)
5) Titan – almost certainly …
6) Charon -probably? (I’d expect it although we won’t know for sure till New Horizons gets there!)
6) Dione -possibily? (if liquid water made of most likely water ice can be called volcanism)
7) Iapetus & some of the other Saturian moons … (ditto) Perhaps Ganymede – etherinpast or prenert at a low level …

Hmmn okay now I’m speculating but still .. seems a lot more than just Io and Enceladus tho’ they are the most dramatic examples.

Thanks Alan Stern and teh NewHorizons team -awesome images &welldone -thanks tooBA for posting them for our enjoyment.

Could someone please tell me what “Liquid Metallic Hydrogen” would look/feel like if you could hold some in a cup? Would it look/act like mercury? I simply cant visualise something I know of as a noble gas being a metallic liquid…

Aah, many Europas ago…

Hey, whaddya mean one of the fastest? I thought NH was the fastest. Is it, or not really?