Martin Brown wrote:
On 14/02/2012 10:53, Dave Liquorice wrote:
On Tue, 14 Feb 2012 09:23:38 +0000 (UTC), Tim wrote:

I thought it was hollow with mirrors glued to the outside.

Has fecking google groups broken this thread into two halves?

Maths in the other half indicates that it is solid.

It's solid with small retro reflective mirror clusters set into
holes in the surface.

The holes could account for the approx 100kg difference between the
stated mass and the calculated one.

Reckoned to be the densest object in the solar system.

That I'm not convinced about that. How dense is the centre of the
sun?

Digging about there is some "disagreement" on the density of metals
but platinum (21.4g cm^3) is generally quoted with a density higher
than tungsten (19.6g/cm^3)(*). Variously uranium and plutonium are
quoted above or below tungsten, sometimes by quite a lot less!

Of the platinum group metals osmium is the densest at 22.48 just
sightly ahead of iridium 22.42 and well ahead of platinum 21.45.

Tungstens other claim to fame if highest melting point of any metal
and a coefficient of expansion that conveniently matches borosilicate
glass.

(*) Wrongipedia said 19.25 last night but several other sources "out
there" this morning say 19.6 g cm^3.

http://www.lenntech.com/periodic-cha...ts/density.htm

I think tungsten is generally taken to be around 19.35

Even if it isn't the densest element, I suspect that it's the densest object
*of that size* in the solar system. There can't be that many big lumps of
the other purified elements around.

Tim