Has NASA Discovered Evidence for Extraterresterial Life?

[chemisttree]

All the buzz is that NASA has found out something important.

http://www.nasa.gov/home/hqnews/2010/nov/HQ_M10-167_Astrobiology.html

 

[Greg Bernhardt]

Universe Today seems to downgrade the event
http://www.universetoday.com/80817/calm-down-nasa-hasnt-found-any-aliens/

Exciting none-the-less! Any new findings are welcome findings!

 

[DaveC426913]

What do you suppose the nature of the "discovery" is?

 

[Ygggdrasil]

Could possibly be publication of a paper based on data from the Kepler Space Telescope's search for Earth-like planets. The research was mentioned at a TED talk a little while ago and caught by some science news websites (http://news.discovery.com/space/kepler-scientist-galaxy-is-rich-in-earth-like-planets.html).

[edit: actually after reading the link Greg posted, it seems like the paper is on arsenic biochemistry and implications for the origin of life. Still sounds pretty exciting.]

 

[hamster143]

I can't find a single article that is coauthored by more than two of the five participants. Voytek is probably just an administrator. Wolfe-Simon coauthored one article with Elser (about the role of molybdenum in bacteria, not too exciting and apparently unrelated to astrobiology) and one article with Benner (regarding signatures of life based on alternative types of biochemistry). There is another article, mentioned by Universe Today as well, that discusses the possibility of having life forms that use arsenic instead of, or in addition to phosphorus.

The last participant, Pamela Conrad, works at the Virtual Planetary Laboratory. To quote: "The Virtual Planet Laboratory (VPL) is a team of scientists who are using the best supercomputers available to simulate Earth-sized (terrestrial) planets. VPL's goal is to discover the likely range of habitable planets around other stars and to find out how these planets might appear to future planet-finding missions."

Based on this information, I think that we can rule out discovering evidence of extraterrestrial life. There's a good chance that they'll announce finding that allowing for arsenic-based life forms expands the range of habitability.

 

[Ygggdrasil]

Here's an interesting article from February 2009 that perhaps gives some insight into Thursday's announcement (http://www.cosmosmagazine.com/news/2556/does-earth-harbour-a-shadow-biosphere-alien-life ):

The tools and experiments researchers use to look for new forms of life - such as those on missions to Mars - would not detect biochemistries different from our own, making it easy for scientists to miss alien life, even if was under their noses.

"When you don't know what you're looking for or what it'll look like, you have to come up with a whole scientific method for how to go about [looking for] it," added Steven Benner, a Fellow at the Foundation for Applied Molecular Evolution and The Westheimer Institute for Science and Technology in Gainesville, Florida.

Scientists are looking in places where life isn't expected - for example, in areas of extreme heat, cold, salt, radiation, dryness, or contaminated streams and rivers. Davies is particularly interested in places that are heavily contaminated with arsenic, which, he suggests, might support forms of life that use arsenic the way life as we know it uses phosphorus.

It seems that researchers may have discovered life on Earth that uses novel biochemistries based on arsenic (certainly a discovery worth publication in Science). If this is the case then this discovery, in some senses, is more exciting than finding evidence of alien life on another planet (at least to a biochemist like me). This is in essence an "alien" life-form, but it lives on Earth and can be more easily studied than some hypothetical life in a far away solar system.

It remains to be seen just how different these arsenic-metabolizing organisms are from other life. Are they merely standard, run-of-the-mill microbes that have adapted to metabolize arsenic, thus providing a proof of principle of arsenic biochemistry (the more likely scenario)? Or might they represent a more ancient form of life that preceded or evolved in parallel with modern organisms (very unlikely, but if this were the case it would be an extremely significant finding)? Of course, this could all be idle speculation and the paper could be on something completely different.

Either way, I'm now eagerly awaiting this week's issue of Science.

 

[bobze]

Well the hype has got me all giddy :)

 

[FlexGunship]

http://www.nasa.gov/home/hqnews/2010/nov/HQ_M10-167_Astrobiology.html]...to[/PLAIN] discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.

If nothing else, we will be able to refine the Drake equation by an iota or more.

 

[FlexGunship]

It seems that researchers may have discovered life on Earth that uses novel biochemistries based on arsenic (certainly a discovery worth publication in Science).

I think your conclusion might be premature. I read that to mean that someone has thought of a way that this could be possible. Not that there are actually candidates for life that works this way.

I would put it on par with that movie Evolution where anti-dandruff shampoo with selenium was the arsenic-equivalent for nitrogen based lifeforms.

 

[Mu naught]

I hate the way people/the media hype everything up. We're living in the age of exaggeration.

 

[Oxieee]

I hate the way people/the media hype everything up. We're living in the age of exaggeration.

VERY true...more over i do get irritated by the term " might possibly " or " may one day "
where our modern science to confirm and then tell what's what

 

[Redbelly98]

When I heard about this upcoming announcement, I tried to think of where on the "spectrum" of searching for alien life this might fit. By "spectrum", I mean where on the following list this news could fall:

1. Finding conditions compatible with supporting life.
2. Finding direct evidence that life once existed.
3. Finding life.
4. Finding intelligent life.

I'm guessing this would have to be at level 1, or (remotely possible) 2. We'll see tomorrow.

 

[Greg Bernhardt]

3. Finding life.
4. Finding intelligent life.

I'm guessing this would have to be at level 1 or 2. We'll see tomorrow.

I could be wrong, but I would find it hard to believe there wouldn't be a leak if it was either 3 or 4. That kind of news would get around very quickly and difficult to contain.

 

[hamster143]

There's also level 0 - speculating about conditions that could be compatible with supporting life. Since none of the participants of the conference strike me as the kind that would be able to find anything physical (they are all theorists), we should be closer to level 0 than to level 2.

 

[Phyisab****]

There's also level 0 - speculating about conditions that could be compatible with supporting life.

I saw this on CNN and thought "holy crap!" But after reading and thinking, I'm going with level 0.

 

[DaveC426913]

Level 5. We the scientists are the aliens, and are now your overlords. This meeting is to lay out the new Rules for Approved Human Activities.

 

[Ygggdrasil]

I think your conclusion might be premature. I read that to mean that someone has thought of a way that this could be possible. Not that there are actually candidates for life that works this way.

There's also level 0 - speculating about conditions that could be compatible with supporting life. Since none of the participants of the conference strike me as the kind that would be able to find anything physical (they are all theorists), we should be closer to level 0 than to level 2.

I doubt that a purely theoretical paper speculating about the possible biochemical conditions of extraterrestrial life would make it into Science. There is reason to think that there could be some organisms with novel arsenic biochemistry. For example, in 2008, a team led by the US Geological Survey found organisms that could photosynthesize using arsenic in a lake in California (Kulp et al. Arsenic(III) Fuels Anoxygenic Photosynthesis in Hot Spring Biofilms from Mono Lake, California. Science 321: 967 (2008). http://dx.doi.org/10.1126/science.1160799).

My guess would be that the NASA team developed new methods for seeking evidence of arsenic metabolism (methods which could possibly be used in future space probes) and validated these methods by seeking arsenic-metabolizing microbes in Mono lake or other similar areas. Finding and sequencing more arsenic-metabolizing bacteria would be helpful as it would provide more data to help determine whether the ability to metabolize arsenic originated recently or represents a more ancient form of life perhaps present on the early earth.

 

[bcrowell]

Arsenic-based life tastes like chicken, but I hear it's not good for you.

 

[Ivan Seeking]

Perhaps?

Could the Mono Lake arsenic prove there is a shadow biosphere?
Do alien life forms exist in a Californian lake? Could there be a shadow biosphere? One scientist is trying to find out.

Mono Lake has a bizarre, extraterrestrial beauty. Just east of Yosemite National Park in California, the ancient lake covers about 65 square miles. Above its surface rise the twisted shapes of tufa, formed when freshwater springs bubble up through the alkaline waters.

Felisa Wolfe-Simon, a geobiologist, is interested in the lake not for its scenery but because it may be harbouring alien life forms, or “weird life”. Mono Lake, a basin with no outlet, has built up over many millennia one of the highest natural concentrations of arsenic on Earth. Dr Wolfe-Simon is investigating whether, in the mud around the lake or in the water, there exist microbes whose biological make-up is so fundamentally different from that of any known life on Earth that it may provide proof of a shadow biosphere, a second genesis for life on this planet...

http://www.timesonline.co.uk/tol/news/science/eureka/article7040864.ece

 

[DaveC426913]

Simon is investigating whether, in the mud around the lake or in the water, there exist microbes whose biological make-up is so fundamentally different from that of any known life on Earth that it may provide proof of a shadow biosphere, a second genesis for life on this planet...

Question about this arsenic thing. It's a substitute for phosphorus, right? But it's not a substitute for COHN-, or even RNA/DNA-based life, right?

This hypothetical arsenic-based life is still organic and based on RNA?

Yah, found this on Wiki:

It has been speculated that the earliest life on Earth may have used arsenic in place of phosphorus in the backbone of its DNA

 

[Ygggdrasil]

Question about this arsenic thing. It's a substitute for phosphorus, right? But it's not a substitute for COHN-, or even RNA/DNA-based life, right?

This hypothetical arsenic-based life is still organic and based on RNA?

The hypothetical arsenic-"based" life would still be based primarily on carbon, oxygen, hydrogen and nitrogen. The main difference would be, as said in wikipedia, substitution of arsenic for phosphorus. Felisa Wolfe-Simon and co-authors argue that it is possible that such molecules could exist (without being too unstable to allow life) and why these types of molecules may have been easier for life to use on the early Earth in an article in the International Journal of Astrobiology (abstract below):

"All known life requires phosphorus (P) in the form of inorganic phosphate (PO₄^3- or P_i) and phosphate-containing organic molecules. P_i serves as the backbone of the nucleic acids that constitute genetic material and as the major repository of chemical energy for metabolism in polyphosphate bonds. Arsenic (As) lies directly below P on the periodic table and so the two elements share many chemical properties, although their chemistries are sufficiently dissimilar that As cannot directly replace P in modern biochemistry. Arsenic is toxic because As and P are similar enough that organisms attempt this substitution. We hypothesize that ancient biochemical systems, analogous to but distinct from those known today, could have utilized arsenate in the equivalent biological role as phosphate. Organisms utilizing such 'weird life' biochemical pathways may have supported a 'shadow biosphere' at the time of the origin and early evolution of life on Earth or on other planets. Such organisms may even persist on Earth today, undetected, in unusual niches"​

(Wolfe-Simon, Davies and Anbar. Did nature also choose arsenic? Int. J. Astrobiol 8: 69 (2009). doi:10.1017/S1473550408004394, http://www.ironlisa.com/WolfeSimon_etal_IJA2009.pdf )

In particular see fig 2 for the authors' speculative picture of As-RNA and As-DNA.

I would be absolutely stunned if Thursday's Science paper announced they found As-DNA or As-RNA. I could definitely see other aspects of arsenic metabolism (e.g. using it as an electron donor for the fixation of carbon dioxide) and maybe limited incorporation into some biosynthetic pathways, but an organisms with a form of genetic material chemically distinct from all other known organisms would be a huge discovery.

 

[bobze]

Well I know a lot of people are let down, but I'm pretty excited. Because this has major implications for the origins of life on earth. Arsenic compounds for things like nucleotides form much more readily than phosphorous ones. It may mean that nucleoside arsenates came before nucleoside phosphates.

Pretty cool.

 

[Jack21222]

I would be absolutely stunned if Thursday's Science paper announced they found As-DNA or As-RNA. I could definitely see other aspects of arsenic metabolism (e.g. using it as an electron donor for the fixation of carbon dioxide) and maybe limited incorporation into some biosynthetic pathways, but an organisms with a form of genetic material chemically distinct from all other known organisms would be a huge discovery.

Are you stunned?

It still uses some phosphorus, so it hasn't swapped ALL of it out for arsenic, but still, it's pretty freaking cool.

 

[DaveC426913]

All the buzz is that NASA has found out something important.

http://www.nasa.gov/home/hqnews/2010/nov/HQ_M10-167_Astrobiology.html

Wow. I went to that page and the video completely froze my system - even the mouse (yet the audio played on). I had to do a hard boot recovery.

 

[nismaratwork]

Wow. I went to that page and the video completely froze my system - even the mouse (yet the audio played on). I had to do a hard boot recovery.

Ouch, that's almost as bad as the early speculation on the news networks as to what this announcement was going to be.

 

[Ygggdrasil]

Are you stunned?

It still uses some phosphorus, so it hasn't swapped ALL of it out for arsenic, but still, it's pretty freaking cool.

I was very stunned, then I read the paper, thought about it, and am skeptical of the claim that the bacteria uses As-DNA as its genetic material (it may contain As-DNA, but these would likely be nonfunctional). For my (very longwinded) thoughts on the paper, see my post on the biology board (https://www.physicsforums.com/showthread.php?p=3016806#post3016806).

Despite my skepticism, I still think the paper is very neat and exciting. Who knows what other undiscovered biochemistires are out these in other extreme environments.

 

[_Tully]

A cool discovery (creation?), but I think the hype is overshadowing the fact that we know water can support life without the need of atmosphere or sunlight, we've known this for a long time (I believe ever since we started poking around hydrothermal vents?). Isn't that a bit more exciting, or at least equally so, as we know there is plenty of water elsewhere?

Or has the excitement shifted from the astrobiological implications to biology in general? In which case, yes, very interesting!

 

[Redbelly98]

I am puzzled as to why NASA has any role in this. It is terrestrial biology.

 

[FlexGunship]

According to a new paper published in the journal Science, reporters are unable to thrive in an arsenic-rich environment.

 

[FlexGunship]

I am puzzled as to why NASA has any role in this. It is terrestrial biology.

They funded the research under a branch of exobiology. Basically trying to answer the question: "what else should we look for that might indicate life?"