NASA: arsenic-based life?

[Dr Mordrid]

A major announcement is coming from NASA on Dec. 2, 2010 regarding a finding that will impact the search for extraterrestrial life. From the list of participants it's very likely to involve shadow biospheres.

[Dr Mordrid]

Multiple sources within the Astrobiology community are reporting that NASA's announcement tomorrow concerns Arsenic-based biochemistry, and that it may have happened more than once on Earth. If true this has huge implications for finding life on other planets.

[cjolley]

http://gizmodo.com/5704158/nasa-finds-new-life

Hours before their special news conference today, the cat is out of the bag: NASA has discovered a completely new life form that doesn't share the biological building blocks of anything currently living in planet Earth. This changes everything.

At their conference today, NASA scientist Felisa Wolfe Simon will announce that they have found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic. All life on Earth is made of six components: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same.

But not this one. This one is completely different. Discovered in the poisonous Mono Lake, California, this bacteria is made of arsenic, something that was thought to be completely impossible. While she and other scientists theorized that this could be possible, this is the first discovery. The implications of this discovery are enormous to our understanding of life itself and the possibility of finding beings in other planets that don't have to be like planet Earth.

No details have been disclosed about the origin or nature of this new life form. We will know more today at 2pm EST but, while this life hasn't been found in another planet, this discovery does indeed change everything we know about biology. I don't know about you but I've not been so excited about a bacteria since my STD tests came back clean. And that's without counting yesterday's announcement on the discovery of a massive number of red dwarf stars, which may harbor a trillion Earths, dramatically increasing our chances of finding extraterrestrial life. [NOS—In Dutch]

[Dr Mordrid]

Not only this, but another result announced this week indicates there are 3X as many red dwarf stars as previously estimated. These are the longest lived and the most numerous family of stars, and they have sizeable habitable zones.

This has profound implications for life and for how much missing mass remains in the universe; more stars = less need for things like "dark matter."

[Brian Ellis]

When I first saw "NASA: arsenic-based life?", I said to myself something to the effect of 'bollocks', simply because there is no electronic resemblence to carbon and the number of As-based organic compounds is small. Last night, I heard that the As was a substitute for phosphorus in a conventional C-based organic system. As P and As are electronically similar, this is much more believable. So the life would not be As-based but C-based.

[VJ]

This has profound implications for life and for how much missing mass remains in the universe; more stars = less need for things like "dark matter."

Something I haven't been able to find: does the larger amount of stars completely explains the missing matter (for which dark matter was "invented")? And if not, perhaps there are other normal matter things we cannot see yet? So where would this leave the dark matter theory?

So the life would not be As-based but C-based.

Yes... Of course, maybe our imagination is limiting it to having to be C-based. This discovery really changes what astrobiologists thought they knew, so perhaps there are other things possible they currently are not aware of...?

[Brian Ellis]

Yes... Of course, maybe our imagination is limiting it to having to be C-based. This discovery really changes what astrobiologists thought they knew, so perhaps there are other things possible they currently are not aware of...?

I agree that C is perhaps not the only element that could be a base for life. I would not exclude the possibility of Si or even Ge on very much hotter planets (with or without C mixed in the molecules). Why? Because an essential feature of life is polymerisation and the formation of cyclic compounds (the two going hand in hand). As we know it, methane, CH4, is the simplest organic substance. Ethane, C2H6, can be considered as the simplest polymer or dimer and could be named dimethane. Benzene, C6H6, is the best known cyclic substance, derivatives of which are found in all living creatures. Si could theoretically be substituted for C in all these compounds, although the simplest organic compounds are the silanes which bond with C atoms. The simplest is dimethylsilane H3C-SiH2-CH3, which is the analogue of propane.

I suppose if little green men were based on silicone chemistry, they would be slippery characters!

There is also a possibility of cyclic compounds based on N, such as pentazole, and theoretically phosphorus, but these are considered as inorganic. Pentazole has only one bond to an H atom, against benzene's six; this would very seriously limit its possibility of forming organic molecules.

[Dr Mordrid]

Something I haven't been able to find: does the larger amount of stars completely explains the missing matter (for which dark matter was "invented")?
>
....perhaps there are other normal matter things we cannot see yet?

>....So where would this leave the dark matter theory?
>

a. Not completely, but it takes a significant bite out of what's considered "missing mass."

b. Very, very likely.

c. In transition. With there being at least 10X more red dwarf stars, and them being the largest & longest lived variety, there's a ton of recalculation and debate to be done.

I've never felt very comfortable with exotic matter as a total explanation of "missing" mass. IMO it will be a mix of undiscovered weakly interacting massive (and not so massive) particles (WIMP's), matter that is "invisible" only because of the limitations of our sensing technologies, more black holes & brown dwarfs than currently estimated and adjustments to how gravity works at long distances - perhaps as a result of weak interactions with the electromagnetic force. No need for exotic matter beyond WIMP's.

Getting a big IR telescope like the James Webb Space Telescope up will help with brown dwarfs and other invisible normal matter, if budget overruns don't kill it first, but there's also a lot more theoretical work to be done too.