Expert: Tom Whiting - 3/2/2005

Question
I have been doing a bit of research, and I recently ran into this bit of text:

"A simulation of Neptune's atmosphere was recently done at University of California, Berkeley... and it produced diamond dust. So, they think with all the carbon in Neptune's atmosphere and the extreme pressure on that planet that it may be, literally, raining giant diamonds!"

I thought that carbon made up only a small percentage of Neptune's atmosphere, but then, I'm not an expert. How accurate is this statement above? Thanks so much!

Answer
Hi Asks,
Yes, that was an article published in Oct 1999 at Berkeley
and picked up on, (and probably 'sensationalized' ) by
Space Daily and Science Monster...to sell more magazines
and papers, of course...which most of those publications do.


So it wasn't 'recently'....it was Oct. 1999.

As far as carbon, you are probably right...about free carbon.....being sparse in any gas giant planet's atmosphere.
But all the gas giants are loaded with 'natural gas'...common
name methane, CH4.  (One carbon atom and 4 hydrogen atoms).
(The "4" should be a small sub-script, but a computer, or
my computer can't make a little subscript "4").

So there is a fair amount of carbon, but it's initially tied
up as methane gas.

I went back and re-read the article, released at Berkeley
by Robert Sanders....remember it stated that most of those
alleged diamonds would begin about 1/10 into the planet's
atmosphere where the pressure was high enough to form
them....realize with a radius of about 15,000 miles, this would
be 1500 miles deep into the atmosphere before you meet
up with that kind of pressure.  And that's just the formation
height......
Realize that none of the gas giant planets have a normal
solid surface like the terrestrial planets of Mercury, Venus,
Earth, and Mars....they are 99% gas, mainly methane,
hydrogen, helium and trace of ammonia, until you get down
to a very small solid, rock-like core which is under tremendous heat and pressure....so humans would probably
never visit a gas giant planet directly, but rather explore
it at a distance, like land on one of their moons, where there
is a normal solid surface.  So it's unrealistic to assume that
humans could ever "mine" the alleged pure carbon
(diamonds) down on, or near the core of a gas giant.
An easier place where diamonds might exist, would be
in the asteroid belt....at least there is a possibility at that
location.
How accurate is the "raining diamond" hypothesis?
Only God knows.  It's all theorized by
Earthly experimentation and hypothesis....at Berkeley.
What the actual conditions are, no one really knows.
And won't, until we humans do what we just recently did
on Titan....send a probe down to find out.
Clear skies,
Tom Whiting
Erie, PA