Kevin's Watch

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

This is a first - a bacteria has been found that uses Arsenic to make its DNA and other components in place of Phosphorous.

This makes it unlike any other known lifeform.

I don't know much about this stuff, but, if I understand what I'm reading, the word "extraordinary" doesn't even approach it! I can't imagine why such things would be considered impossible. They've been doing it in sci-fi forever. But to actually find one... A form of life that is unique (afawk) in such an incredible way.

I assume there will be lots more of this in the news in the next couple days.

I've been wondering about this kind of thing for so long, cuz even in crappy cow country high school chemistry we were taught how vertical columns share certain properties...and in our crappy SF library section, there were real scientists who also do SF speculating.
Way so super cool that they found it right here.
One more evidence step in my belief that, contrary to the "life is so unlikely" school, life is practically inevitable...lots of life...lots of places.

[though I have to say...the announcement lead up to the story led me to expect something much more....poo poo on the PR departments].

Yeah, with it being NASA who found it, I assumed it was out there somewhere. Heh

Hahaha, they did it deliberately of course.

As for life, I don't think it's necessarily likely. It's just that the universe is so big that even a tiny possibility still adds up to a respectable number.

If life is present only once in each galaxy, we're still looking at an estimated 125 billion occurrences.

--A

Avatar wrote:Hahaha, they did it deliberately of course.

As for life, I don't think it's necessarily likely. It's just that the universe is so big that even a tiny possibility still adds up to a respectable number.

If life is present only once in each galaxy, we're still looking at an estimated 125 billion occurrences.

--A

I consider 125 billion Avatar-equivalents, typing 125 billion times 35000 KW-equivalent posts to be a sufficiently "packed with life" universe. [oh, and according to the latest cutting edge theory guy, there might be 3 times as many stars as we thought...so multiply all that crap by three, if ya wanna waste the time].

As far as I understand it, this bacterium purportedly incorporates arsenic into its DNA when there isn't enough phosphorus in the surroundings. While direct evidence for the presence of arsenic replacing phosphorus in the bacterium's DNA is still lacking, circumstantial evidence seems to strongly point to this theory as truth.

And yes, if this is demonstrated with direct evidence (for example, by direct detection of arsenic compounds in the bacterium's DNA through biochemical and spectrographical methods), this is a huge deal: it shows that the criteria thus far believed to be universal in terms of how life can develop should be completely rewritten. Then again, personally I always found those criteria very anthropocentric - i.e. the need for water, a carbon-based metabolism, a specific atmosphere, abundant sunlight, and so on. The fact is that in a near-infinite or downright endless universe, it's very arrogant to believe that life could only develop using the same building blocks we have here on Earth. Hopefully this bacterium - alongside those other micro-organisms which have been found in recent years - will enable xenobiologists to expand the definition of how life could present itself in extraterrestrial environments.

This is not the first time that we discover something here on Earth that dramatically alters our understanding of life processes. DId you know that there are bacteria and actually entire ecosystems of multicellular organisms in the depths of the ocean which do not depend on the sun at all? Before their discovery, it was believed that the ultimate source of nourishment of all life on Earth was sunlight, since it nourished plants and photosynthesizing bacteria, which formed the basis for the food web.

The discovery of hydrothermal vents deep beneath the ocean, and the ecosystems thriving in their vicinity, led to the belief that these organisms depended for their survival on detritus falling from the surface of the ocean (deriving from organisms using sunlight), but it was later discovered that most of the creatures living around hydrothermal vents do not depend at all on sunlight, nor do they depend on detritus from the upper layers of the ocean. Rather, they comprise a wholly separate ecosystem, which is independent of sunlight and uses instead geothermal energy as the basis for the food web, thanks to bacteria which thrive on it and serve much the same purpose in that world as plants do in ours.

Just for the record, it's believed that Mars used to have hydrothermal vents in the past, and that Europa (one of Jupiter's moons) has active hydrothermal vents. So between these two discoveries - bacteria using arsenic to build their DNA and ecosystems which do not depend on the sun's energy - we're looking at a dramatic expansion of the possibilities for life outside of Earth.

Yeah, I have to agree on there being an overly anthropomorphic view of life. The whole concept that life is only likely to exist on planets similar to earth strikes me as not much different from people a few centuries back thinking the earth was the centre of the universe.

People tend to think that however they themselves live and came to be is somehow the only way things could be.

Xar wrote:As far as I understand it, this bacterium purportedly incorporates arsenic into its DNA when there isn't enough phosphorus in the surroundings. While direct evidence for the presence of arsenic replacing phosphorus in the bacterium's DNA is still lacking, circumstantial evidence seems to strongly point to this theory as truth.

This is from news.nationalgeographic.com/news/2010/12/101202-nasa-announcement-arsenic-life-mono-lake-science-space/

The scientists cultured Mono Lake bacteria in Petri dishes, gradually increasing the amount of arsenic while reducing phosphorus. Chemical analyses with radioactive tracers showed that the GFAJ-1 strain bacteria was in fact using arsenic in its metabolism.

Isn't that direct evidence?

Xar wrote:This is not the first time that we discover something here on Earth that dramatically alters our understanding of life processes. DId you know that there are bacteria and actually entire ecosystems of multicellular organisms in the depths of the ocean which do not depend on the sun at all? Before their discovery, it was believed that the ultimate source of nourishment of all life on Earth was sunlight, since it nourished plants and photosynthesizing bacteria, which formed the basis for the food web.

The discovery of hydrothermal vents deep beneath the ocean, and the ecosystems thriving in their vicinity, led to the belief that these organisms depended for their survival on detritus falling from the surface of the ocean (deriving from organisms using sunlight), but it was later discovered that most of the creatures living around hydrothermal vents do not depend at all on sunlight, nor do they depend on detritus from the upper layers of the ocean. Rather, they comprise a wholly separate ecosystem, which is independent of sunlight and uses instead geothermal energy as the basis for the food web, thanks to bacteria which thrive on it and serve much the same purpose in that world as plants do in ours.

I've known about the life around the hydrothermal vents for years, but never knew - heck, never imagined - they were a wholly separate ecosystem! That's awesome!!

Fist and Faith wrote: I've known about the life around the hydrothermal vents for years, but never knew - heck, never imagined - they were a wholly separate ecosystem! That's awesome!!

If I'm not mistaken [and I might be] there's similar in deep rock...not only don't use sunlight, use almost no water either.

Xar wrote:Then again, personally I always found those criteria very anthropocentric - i.e. the need for water, a carbon-based metabolism, a specific atmosphere, abundant sunlight, and so on. The fact is that in a near-infinite or downright endless universe, it's very arrogant to believe that life could only develop using the same building blocks we have here on Earth.

Very much agree. The point about alien life is that it will be alien. We won't even necessarily have a relevant frame of reference for it.

--A

Some opposition. www.slate.com/id/2276919/?GT1=38001 I haven't read it yet, so don't know what the specific points are.

Possible problems with procedures and methodology, which doesn't mean the NASA people are wrong, but it might.

They say we should know the truth soon, cuz supposedly it's pretty easy to check.