OT: Extrasolar planets discovered directly

[Ron_Lugge]

This looks like a grenade to me...

http://redwing.hutman.net/~mreed/war...tm/grenade.htm

[narf poit chez BOOM]

Oh, don't worry. We've had religious discussions and we still like each other.

* PS: Fyron, that package you are holding isn't a bomb. Please shake it a few times for me, please.

[Strategia_In_Ultima]

HUH what are you talking about? This is a discussion about extrasolar life forms.....

oh but if your e-mail server is giving you problems you can open a Hotmail account temporarily and change your email adress in your profile to that adress until your original email account is back. That is, if you're talking about your account here..... otherwise, you could also open the hotmail account anyway and forward all the mails you want to keep, contacts etc. there.

[Raging Deadstar]

Ron_Lugge said:
This looks like a grenade to me...

http://redwing.hutman.net/~mreed/war...tm/grenade.htm

Funny Site, thanks.

Nah, I would say it's a bit extreme to call this thread a Grenade. What kind of peaceful utopia forum do you come from? Shrapnel here is usually great for mature posters and not the typical internet crowd (As Narf said, the Political and Religious threads do get slightly toasty at times though.) We have these conversations safe in the knowledge that it won't explode.

But dam, Do you come from the Heaven of Forums? The uBB Of Eden?
Imagines a utopian paradise, long sprawling forests, hills, rivers and lakes. A beautiful almost clear sky, animals graze peacefully. Then the Phong's Head Bar and Grill lot charge through...

[narf poit chez BOOM]

Actually, I think these arguements draw us together.

/me throws some popcorn. 'Boo! Hiss! I want more arguements! What is this, a sewing convention?'

[Renegade 13]

We should not ignore it. But it is difficult to predict the incidence of life in the universe when we do not even know all the viable forms it could take.

[Hunpecked]

Strategia and Renegade make the point that "life" in our galaxy need not be of a sort familiar to us, i.e. carbon-based. This is certainly valid (within the limits of our knowledge), and makes irrelevant any probability calculations requiring Earth-like conditions. Of course it's only natural to look for more-or-less familiar life forms first: we already have one example of a carbon-based ecosystem, but exactly zero examples of any other type.

What forms could "unconventional" life take? I vaguely recall a juvenile science fiction novel which featured Mercurian creatures that resembled ball lightning. Arthur C. Clarke wrote a short story ("Out of the Sun" ???) in which an electromagnetic entity of some sort was ejected from the sun in a solar flare. Silicon seems to be a popular basis for sci fi life forms, probably because of its position just below carbon in the Periodic Table. If I recall correctly the "Horta" of Star Trek fame (episode "Devil in the Dark") was silicon-based.

Nevertheless, silicon is not carbon. As I recall from my prehistoric chemistry classes, silicon's 4 valence electrons are one electron shell "out" from carbon's, giving the elements roughly similar but far from identical chemical properties. For example, silicon does form polymer chains (as the bosoms of countless Hollywood starlets attest), but I've read (I'm no chemist) that these chains don't approach the length and complexity of carbon polymers (DNA, anyone?). Recall also that silicon dioxide is a solid at temperatures that vaporize carbon dioxide. Now some earth organisms (e.g. diatoms, sponges) take advantage of that and use silicon dioxide STRUCTURALLY, but on Earth at least evolution has favored carbon chemistry for life's vital functions, despite the greater abundance of silicon.

Incidentally, as a naive layman I wonder if a detailed study of the ways these creatures build their silica frameworks might suggest how a hypothetical silicon-based life form could "work".

A couple of places on the web with some tidbits about silicon:

http://en.wikipedia.org/wiki/Silicon_dioxide

http://www.webelements.com/index.html (click on the elements)

[Fyron]

There are silicon-based lifeforms on the Earth right now... They are all monerans, nothing complex, but they are out there.

[Hunpecked]

Interesting. I wasn't aware that any Monerans formed silicaceous structures. Protistans, yes. Any references on the web?

[Fyron]

Dunno. It was in a scientific journal of some sort I read several years ago. A quick google turned up this mention to an upcoming book. No idea if this is a reputable site or not, but there it is:

http://www.gsreport.com/articles/art000035.html