NASA Finding re Extraterrestrial Life

[RealityRules]

Loki had it at post #5 http://skymania.com/wp/2010/11/alien...-on-earth.html

Microbe found that substitutes Arsenic (As) for Phosphorus (P) in DNA and other molecules like ATP.

Both are close in the periodic table and have similar characterisitcs.

en.wikipedia.org/wiki/Arsenic#Physical_characteristics

http://en.wikipedia.org/wiki/Arsenic#Compounds

Previously had considered 6 essential "building-block" elements in organic chemistry - C, N, O, H, P and S.

This is a substitution of one of the "biggies" !!

As is not toxic at low concentrations - it has been a used as a tonic and appetitie stimulant in animals and humans. It was implicated in Phar Lap's death (Phar Laps strapper seemed to be using it, but there was a view a "higher-than-tonic" dose was administered)

http://en.wikipedia.org/wiki/Phar_Lap#Death

Implications for

1. consideration for formation of all "biomolecules" (organic chemicals/molecules) including all biological life on earth*, and
2. what they look for in
   1. other environs on Earth, and
      
   2. in other environs outside Earth.

* referred to evolutionary incorporation of microbes as intra-cellular organelles in all mammalian cells.

Implications for instrumentation used in extra-terrestrial exploration.

[Aldaron]

Well, talk about a disappointment. Interesting? Certainly. Impacting on the chances of ET life? Possibly (depending on how you view the Drake equation). But world-shattering news? Hardly.

I set my alarm an hour early to get up and learn about it...now I wish I'd slept in!

[Aldaron]

Well...that'll teach me to rely on the ABC to report science news. I read some article about discovering there are more dim red dwarf stars in other galaxies, possibly increasing the chances of ET life. Got disappointed and posted...and then read their updated page with the arsenic-based bacteria story on it!

[Fromm_Nicht]

Originally Posted by Aldaron

Well...that'll teach me to rely on the ABC to report science news. I read some article about discovering there are more dim red dwarf stars in other galaxies, possibly increasing the chances of ET life. Got disappointed and posted...and then read their updated page with the arsenic-based bacteria story on it!

I thought you must have been mad after reading that first post .

It may just be the scientist in me but this is a very exciting announcement, it changes the way we have to think about biomolecular science and about what conditions are required for life to develop.

[Loki]

They have been talking that work up and linking it to extraterrestrial life for years. I think they have somewhat missed the point. Yes it is very interesting work with implications for our understanding of a whole range of things and will inform how we go about searching for and detecting extraterrestrial life. However to associate it so strongly with extraterrestrial life and in effect downplay the actual significance of the work perplexes me.

My largely uninformed opinion only.

[Fromm_Nicht]

Originally Posted by Loki

They have been talking that work up and linking it to extraterrestrial life for years. I think they have somewhat missed the point. Yes it is very interesting work with implications for our understanding of a whole range of things and will inform how we go about searching for and detecting extraterrestrial life. However to associate it so strongly with extraterrestrial life and in effect downplay the actual significance of the work perplexes me.

My largely uninformed opinion only.

Well, yeah, the only real significant discovery in the search for extraterrestrial life would be the discovery of such life itself. The significance I mean to emphasise is that it shows that very specific circumstances are not necessarily required for the development of life. It seems a fairly hefty kick in the gut to the "fine-tuned universe" argument of the religious, but it also opens up enormous opportunities for bio-engineering.

[Xeno]

I allow this discovery suggests life could develop under different conditions but the actual bacterium thrives with Phosphorous. It can also use Arsenic. That is, it appears to be common life which has adapted to the extent of being able to use either Phosphorous or Arsenic in its DNA depending on concentrations available, but is not new life based on As instead of P.

[Loki]

PZ does a good job of explaining it all and why it's not extraterrestrial or even terribly exiting at pharyngula

[Aldaron]

Originally Posted by Loki

PZ does a good job of explaining it all and why it's not extraterrestrial or even terribly exiting at pharyngula

Actually, Pharyngula has missed the point. The media has hyped this as "extra-terrestrial" life. NASA - and the scientists involved - have said no such thing. What they have said is that it demonstrates that something other than CHNOPS can be used in DNA. That had never been observed prior to this particular bug. The fact that arsenic had previously been theorised as a possible replacement for phosphorous is now confirmed by observation.

If it can happen here, it can happen elsewhere. The excitement NASA is feeling is quite justified, IMO. They have just expanded the parameters - we no longer have to speculate on whether something other than carbon, hydrogen, nitrogen, oxygen, phosphorous and sulphur can be used in DNA. We now know it can.

[Goldenmane]

Originally Posted by Aldaron

Actually, Pharyngula has missed the point. The media has hyped this as "extra-terrestrial" life. NASA - and the scientists involved - have said no such thing. What they have said is that it demonstrates that something other than CHNOPS can be used in DNA. That had never been observed prior to this particular bug. The fact that arsenic had previously been theorised as a possible replacement for phosphorous is now confirmed by observation.

If it can happen here, it can happen elsewhere. The excitement NASA is feeling is quite justified, IMO. They have just expanded the parameters - we no longer have to speculate on whether something other than carbon, hydrogen, nitrogen, oxygen, phosphorous and sulphur can be used in DNA. We now know it can.

In limited scenarios, yes.

*waits to see if, for example, similar situations can be demonstrated for silicon. You know what I'm talking about.*