Re: Hammer's Slammers

Geo-Hex wrote:
> Isn't that the dark greenish layer of muck used to date asteroid hits
> on the earth??

It's an element that is found more often in space objects than in the
Earth, so can be used to determine if an meteor or something has 
impacted in an area (the rationale being that if you find 
concentrations way above the baseline, then you've got a probably
strike.)

It's used as evidence in the 'Asteroids killed the Dinosaurs" theory,
as at the depth in the Earth corresponding to 65 million years ago,
there's a very thin layer of Earth where the concentration of 
iridium is above the baseline.

Some facts:

Symbol: Ir, Atomic Number: 77, Atomic Weight: 192.217
Colour:  Silvery White

The name iridium is appropriate, for its salts are highly coloured.
Iridium is
white, similar to platinum, but with a slight yellowish cast. It is very
hard
and brittle, making it very hard to machine, form, or work. It is the
most
corrosion resistant metal known, and was used in making the standard
metre bar
of Paris, which is a 90% platinum-10% iridium alloy. This metre bar has
since
been replaced as a fundamental unit of length (see Krypton). 

Iridium is not attacked by any of the acids nor by aqua regia, but is
attacked
by molten salts, such as NaCl and NaCN.

Courtesy of:
http://www.shef.ac.uk/~chem/web-elements/index.html

>From the WWW site, they do a comparison of hardness, density, and 
other physical factors.  Iridium is toward the top in terms of 
density, middle in terms of hardness, and a very high melting point
(though not as high as Osmium, another element that appears in 
the Slammers books.)  (It also becomes a superconductor at 
0.1125 Kelvin, for those who are interested in really useless facts.
(8-) )

J.

-- 
 *** Jerry Han - jhan@idigital.net - http://www.idigital.net/jhan ***
 "There's a tug of war between what I can and can't feel
		    The inevitable compromise determines the real..."
	 "Battle of Someone" - Blues Traveller - TBFTGOGGI