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Posting-Version: version B 2.10.1 6/24/83; site mmintl.UUCP
Path: utzoo!linus!philabs!pwa-b!mmintl!franka
From: franka@mmintl.UUCP (Frank Adams)
Newsgroups: net.sf-lovers
Subject: Re: what an advanced race would ...
Message-ID: <490@mmintl.UUCP>
Date: Tue, 16-Jul-85 13:53:35 EDT
Article-I.D.: mmintl.490
Posted: Tue Jul 16 13:53:35 1985
Date-Received: Sat, 20-Jul-85 04:27:58 EDT
References: <7800024@orstcs.UUCP>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Multimate International, E. Hartford, CT
Lines: 25
Summary: Hydrogen is more common than that


In article <7800024@orstcs.UUCP> richardt@orstcs.UUCP (richardt) writes:

>Not too long ago, Someone mentioned that Hydrogen and Oxygen were
>two of the most common elements in the universe.  Therefore, why 
>invade a defenseless Earth to get (possibly polluted) water?  They
>forgot one major fact:  Most of that hydrogen is tied up in stars.
>Now I don't know about you, but I'm not going to go and skim a star 
>for hydrogen any time soon.  Especially Rigel!

Maybe most of the hydrogen is tied up in stars (this isn't quite clear,
since we don't know exactly how much non-stellar material is floating around
in the universe.  But we do know certain minimums.)  But if you leave out
the stars entirely, and count only non-stellar matter, hydrogen is still
the most common material in the universe -- probably a larger fraction
than what is in the stars.  (Stars convert hydrogen to other things.)

Why then, you ask, is hydrogen so (relatively) rare as it is on Earth?
The reason is that the sun, early in its existence, blew it all (mostly)
away into space.  Thus small worlds near stars are hydrogen-depleted.
The only other things in the universe (as far as we know) which are hydrogen-
depleted are large, old stars or the remnants of same (white dwarfs,
neutron stars, etc.)  In particular, all the giant planets in our system
(one of which, Jupiter, contains a majority of the non-stellar mass in the
system) are all mostly hydrogen, and their satellites are not short of
hydrogen.