Hey all. I know I haven't been posting much lately, but I've been working for a large software company located in Redmond WA for the last couple of months, and I've barely had a spare minute. BUT...just moments ago I finally caught up with my back brin-l mail.
I've kind of bit my tongue with all the Israel-US-Europe stuff, since although I have some opinions about it I'd rather see the list go in a different direction...more science, more philosophy, more history, more culture (y'know--like movies--n teevee--n stuff). So in that spirit I'm jumping onto the chlorine bandwagon. Why is chlorine imagined as an alternative to oxygen? Well, we breathe oxygen because it is so highly electronegative. It is the 2nd most electronegative element in the universe, after Flourine. And Chlorine comes in 3rd. So why aren't there chlorine and flourine breathing aliens out there? Well, there could be. I think the chemistry of chlorine and flourine would allow it. BUT...nuclear physics makes it unlikely. Just look at the list of the most common elements in the universe. Hydrogen first, sure. Then helium, which is useless for life (barring helium-2 life). Then comes the holy trinity of nitrogen, carbon and oxygen. These most common volatile elements are the basis for life on earth. But why are they so common? Well, it's just the way fusion works. Some elements are preferentially created and some are not. And it just happens that the halogens which would be interesting molecules to use in living systems are not created nearly as often as C, N, and O. I'm sure Alberto or somebody can find a table listing these frequencies, both in the universe and the earth's crust. So...back in the prebiotic soup that covered earth there just wasn't nearly as much chlorine and flourine as there was oxygen. Which means it wasn't part of the chemical toolkit of the first proto-organisms. A planet rich in chlorine could have chlorine breathers, but how could a planet rich in chlorine form? It would have to have a very unusual history to be enriched in chlorine, whereas just about every planet in our solar system is crawling with oxygen, albeit bound up in rocks and such. Since chlorine rich worlds are unlikely, therefore chlorine using ecosystems are also unlikely. ===== Darryl Think Galactically -- Act Terrestrially __________________________________________________ Do You Yahoo!? Great stuff seeking new owners in Yahoo! Auctions! http://auctions.yahoo.com
