A Question on possible alien lifeforms.

[Killy_Mcgee]

Alright so right just now, I was browsing ITN, and I saw the thread that said Europa had really Oxygenated oceans. And that's all great and all and it's a huge scientific discovery, [U][B]but it also said that it had a higher chance of life than other places.[/B][/U]

Now, that's the thing that gets me. I mean, I have not seen a single article which could even agree with the possibility of life being on Pluto or Venus or the Sun for that matter. I mean, Plant's breath CO2, and Archaeobacteria or however you spell it lives off of incredibly high temperatures and no sun. I haven't seen any articles stating the possibility of Iron based life forms or Arsenic based life forms. Why is this?
Can someone explain why?

[wheresmyfish]

I've read this about six times and I still have no idea what you're asking.

[Athena]

Because iron and arsenic are not the fundamental building blocks of organic chemistry like Carbon, Hydrogen, Oxygen and Nitrogen are; metals behave completely different.

[Athelus]

[QUOTE=Athena;17779907]Because iron and arsenic are not the fundamental building blocks of organic chemistry...[/QUOTE]

However there have been speculations over the existence of Arsenic based life on Earth, or at least organisms which rely on arsenic;

[url]http://www.newscientist.com/article/mg19826533.600-early-life-could-have-relied-on-arsenic-dna.html[/url]
[url]http://news.bbc.co.uk/1/hi/sci/tech/7558448.stm[/url]
[url]http://www.astrobio.net/index.php?option=com_expedition&task=detail&id=3259[/url]

[Maucer]

[url]http://en.wikipedia.org/wiki/Chemosynthesis[/url]

:)

[DainBramageStud]

Iron and Arsenic cannot form complex chain-molecules as far as I am aware, so self-replicating macromolecules are out of the question. The best chances for non-carbon extraterrestrial life is either silicon- or nitrogen-based beings. The life-form will also need a decent solvent, so either water or ammonia.

[Athelus]

[QUOTE=DainBramageStudios;17781019]Iron and Arsenic cannot form complex chain-molecules as far as I am aware, so self-replicating macromolecules are out of the question. The best chances for non-carbon extraterrestrial life is either silicon- or nitrogen-based beings. The life-form will also need a decent solvent, so either water or ammonia.[/QUOTE]

Sulfur can form complex molecules, silicon is generally ruled out as being possible as a basis for life forms.

Also arsenic is simmilar enough to phosphorous, a key component in DNA. It can in some microbes actually replace it, and many theories suggest that the earliest DNA was indeed arsenic based.

[johanz]

I doubt there is like in our system.

[Triumph Forks]

[QUOTE=Killy_Mcgee;17779849]Alright so right just now, I was browsing ITN, and I saw the thread that said Europa had really Oxygenated oceans. And that's all great and all and it's a huge scientific discovery, [U][B]but it also said that it had a higher chance of life than other places.[/B][/U]

Now, that's the thing that gets me. I mean, I have not seen a single article which could even agree with the possibility of life being on Pluto or Venus [b]or the Sun for that matter[/b]. I mean, Plant's breath CO2, and Archaeobacteria or however you spell it lives off of incredibly high temperatures and no sun. I haven't seen any articles stating the possibility of Iron based life forms or Arsenic based life forms. Why is this?
Can someone explain why?[/QUOTE]

:wtc:

[bigdoggie]

[QUOTE=johanz;17781301]I doubt there is like in our system.[/QUOTE]

While I have my doubts, the universe never seizes to amaze me, so

[DainBramageStud]

[QUOTE=Athelus;17781225]Sulfur can form complex molecules, silicon is generally ruled out as being possible as a basis for life forms.

Also arsenic is simmilar enough to phosphorous, a key component in DNA. It can in some microbes actually replace it, and many theories suggest that the earliest DNA was indeed arsenic based.[/QUOTE]

Really? I always thought silicon was a good candidate ... :confused:

[matark]

All of the known organisms are carbon based. Obviously, this is because all known organisms are based on Earth, but until there is proof of silicon based organisms or something other than Carbon, scientists cannot assume they exist (and must indirectly assume they don't exist).

[Cheesemonkey]

[QUOTE=Athena;17779907]Because iron and arsenic are not the fundamental building blocks of organic chemistry like Carbon, Hydrogen, Oxygen and Nitrogen are; metals behave completely different.[/QUOTE]

What he's asking is, why aren't there other life forms not like the life forms we have now?

What we know are carbon based life forms, but there may be other life forms that perform radically different on a chemical scale.