How to Stalk Your Scientist Colleagues - The NASA Astrobiology Announcement Revealed! Arsenic life exists!

Sadly, NASA’s press announcement failed to be the alien UFO disclosure we were all hoping and wishing for. Even the more reality-based speculation about discovering evidence of microbial life on Mars or Titan turned out to be a bust. But one lonely blogger did some foot work and guessed the results of the paper nearly a full day in advance of the embargoed publication date. While the majority of the people on earth probably do not understand or even care about the result, it is probably the most significant finding since the components of DNA were originally parsed.

There was a Star Trek Episode where the crew finds a silicon based life form buried in a deep mine on an alien planet. (Geek Alert Season 1, Episode 25 The Devil in the Dark, the silicon based life form is the Horta)

(Photo from http://en.wikipedia.org/wiki/The_Devil_in_the_Dark)

The idea was that the carbon in our DNA can be replaced by silicon, an atom that is right above carbon on the Periodic Table, and so is capable of performing many of the same chemical reactions. While nobody has found a silicon DNA or protein component, this new paper announces a similar substitution of a life-sustaining atom in a real-live Earthling bacteria.

The Science paper, announced today in a NASA Press Release briefing, states that the phosphorus found in DNA is replaced with arsenic in a strain of bacteria found in Mono Lake, CA. Here is the Science abstract. http://www.sciencemag.org/content/early/2010/12/01/science.1197258  But there is a significantly more detailed summary on the Arizona State University website that was pointed to me by my ASU mentor Ariel Anbar, a coauthor. http://asunews.asu.edu/20101202_arsenic

The significance of the announcement is that if substitutions for life-necessary elements can be found, then it is feasible that life processes can occur by entirely different chemical paths than what we generally find here on earth. Instead of looking for a fairly strict ratio of elements that we find in DNA, the search for life must be expanded to include any number of possible permutations that could lead to life. And the best part is that, at this time, we can not necessarily predict what elements will lead to life.

All in all, very cool. It tickles me a little bit to have worked in one of the labs that produced these results, even for a few months, without success on my project. Ariel’s a good guy and I anticipate many more significant results coming from the Keck lab at ASU.

Also, as a note, one of the big side issues that came out of this story is how the Science and Nature embargo system in tandem with the highly suggestive NASA press release caused trouble. I have a strong feeling that the scientists who wrote the paper felt like they were hogtied during the embargo while crazy speculation bounced around the internet. Additionally, the press release was extremely suggestive and lead to a lot of hype in a fairly technical topic that may have harmed the public confidence in science. I hope there are some lessons learned from this announcement that will be considered in future press releases.     

How to Stalk Your Scientist Colleagues - Speculation on the NASA Astrobiology Announcement

There was a pre-announcement at NASA HQ today on a big Astrobiology announcement coming this Thursday.  This story is too good to pass up. First, I want to look at the woo crystal ball and predict what will hit the news and then take a deeper look at what the announcement might actually be about.  Looking back at the old astrobiology questions is fun and interesting.

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

The Woo Crystal ball

I read about this story first from Phil Plait, the Bad Astronomer on his blog earlier today "Snowballing Speculation over a NASA Press Conference", and then by a movie director friend on Facebook. By that time, I figure the story must have hit the mainstream.  The Woo Crystal Ball says that an announcement from NASA about Astrobiology MUST be about the discovery of life on a different planet, maybe one of those rovers finally caught undisputable proof of a little green man or a Mars weed or something…some will say that it will be final disclosure that alien visitors have been with us on Earth for some time now.

This is silly. But I do hope that this week’s Mysterious Universe will be recorded before the Announcement so I can get a summary of what people are saying.

What the Announcement Might Actually Be About

The NASA Press Release gives very few details, but it gives a list of scientists and this sentence describing the meeting “to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life”. The potential of this announcement rings of the ALH84001 announcement, for which President Clinton made a formal announcement including this statement “If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined. Even as it promises answers to some of our oldest questions, it poses still others even more fundamental.” Well, sir, this might sound like an ALH84001 announcement, but it is NO ALH84001.  

As Phil Plait notes, important publications typically have an embargo period where the announcement is held back until the publication date. This is maybe to keep up sales of Nature and Science? In fact, the press release notes that this announcement is under embargo until 2:00pm on Thursday. Because Science, the journal, only reports significant findings, the announcement must be on the results of an aggressive and interesting study. But what could it be?

My first thought was not to speculate about what kind of research is being done in astrobiology or what the open questions are in the field. Nope, my first thought was, what does it take to stalk a scientist? Not very much, below I have the search results of typing in the five authors’ names into Google and tracking down descriptions of their work.  

-     Mary Voytek, director, Astrobiology Program, NASA Headquarters, Washington 

http://astrobiology.nasa.gov/directory/profile/4886/mary/voytek/

‘aquatic microbial ecology and biogeochemistry. She studies environmental controls on microbial transformations of nutrients, xenobiotics, and metals in freshwater and marine systems. She has worked in several extreme environments including Antarctica, hypersaline lakes, deep-sea hydrothermal vents, and terrestrial deep- subsurface sites. At the USGS, she heads the Microbiology and Molecular Ecology team. She has conducted deep-biosphere studies at the Chesapeake Bay Impact Structure.’

-     Felisa Wolfe-Simon, NASA astrobiology research fellow, U.S. Geological Survey, Menlo Park, Calif. 

http://www.ironlisa.com/research/

“a background in molecular biology, biochemistry, and phytoplankton physiology to uncover the sequence of events that shaped the evolution of the modern oceans phytoplankton and life itself.”

-     Pamela Conrad, astrobiologist, NASA's Goddard Space Flight Center, Greenbelt, Md. 

http://astrobiology.nasa.gov/directory/profile/201/pamela/conrad/

Conrad, P.G.,  et al  (2006).  The Bread-crumb trail: distribution of organic chemical biosignatures from cryptoendolithic communities on the surfaces of Arctic and Antarctic sandstone rocks. Astrobiology, 6(1):167.

-     Steven Benner, distinguished fellow, Foundation for Applied Molecular Evolution, Gainesville, Fla. 
http://www.ffame.org/people/sbenner.html

The origin of proteins and nucleic acids 
Ricardo, A Benner, SA 
Planets and Life: The Emerging Science of Astrobiology, ed. Woodruff T. Sullivan and John A. Baross, Cambridge University Press 154-173 (2007)

-     James Elser, professor, Arizona State University, Tempe

http://sols.asu.edu/people/faculty/jelser.php

  “In more recent work he has extended the work to investigate the connections among C:N:P stoichiometry, growth rate, rRNA physiology and genetics, and ecological dynamics in diverse biota and ecosystems and to evaluate the application of these ideas to tumor dynamics. Currently, he is an active member of the ASU’s NASA-funded Astrobiology project “Follow the Elements” and a co-organizer of ASU’s Sustainable Phosphorus Initiative.”

What do these descriptions have in common? What would the focus of a collaborative research effort of one or more of these folks include? Clearly, they all have an emphasis on microbiology, DNA, and evolutionary biology with an emphasis on astrobiology. While it is unclear to me precisely what kind of research this announcement is going to be on, it is clear to me that it is going to be a study on evolutionary geobiology. The youngest scientist, Felisa Wolfe-Simon, a NASA Astrobiology research fellow with grad time working at Dr. Ariel Anbar’s lab at ASU, had the most compelling blurb on her blog “To unravel details regarding the co-evolution of life and Earth.” I think they are going to announce a fundamentally different type of DNA or life process – maybe a non-carbon based chemistry that would support life. How cool would that be?

We’ll see and I’ll follow up with a little blurb Thursday evening!

Bacteria in Deep Rocks, but not really Deep Rocks

Life is found in deepest layer of Earth's crust - environment - 18 November 2010 - New Scientist

www.newscientist.com

An expedition to the deepest layer of the Earth's oceanic crust has revealed an ecosystem living over a kilometre beneath our feet

Bacteria were found in a deep drill hole where life was not expected. Now Sam sent this to me and I think I read the abstract that day too. This guy Sam does some kind of computery work and he rides a bike, but he definately has a sensitive science antenna because it clearly quivered enough for him to recognize that this is a potentially important article.

The idea of microscopic life surviving, and even thriving, in pore spaces or tiny fractures deep underground is not new. Dr. Tom Kieft has been doing this for some time (http://infohost.nmt.edu/~biology/people/faculty/t_kieft/research.html) and his group has been going much deeper than the New Scientist story. The difference is that Dr. Kieft has started at the bottom of deep mines in South Africa (with plans to do similar studies at DUSEL in South Dakota) and drilling down to access even deeper depths. The depths his group could theoretically reach with the infrastructure of DUSEL make the New Scientist study look like they just scratched the surface...and they expect life as far as they can drill. 

So, what's the big deal? They say in the article that they didn't expect to find life in this Gabbro layer, which is right above the mantle. However, careful study of the little cartoon shows that they just hit the very top of the gabbro layer. The substantive difference between the basalt and the gabbro is minimal. There is a relatively small geochemical difference and the crystals are bigger. Both will possess very similar porosities and minerals that the bugs can use to survive. I think as long as the temperatures are low enough to allow proteins to function, there is sufficient chemistry for microbiota to process, and water, you will find life in earth. And life seems to find ways to push the limits of temperature, chemistry, and water that we think will allow them to survive. 


There was one little gem that they mentioned but did not elaborate. They only found bacteria, but no Archaea. Now Archaea are a type of single celled microscopic bug that look, smell and taste just like bacteria, which is why they were not included in the textbooks until recently. For example, Archaea are not to be found in my high school text books. But recent advances in cell culturing, genetic sampling of ground up DNA, and a phylogenetic analysis indicate that Archea are distinct from bacteria and our branch of the tree, eukarotes. Archaea are typically known as the extremophiles that have the ability to live in super-high temperatures or chemical environments that kill off all the other types of life. They also do a lot of interesting geochemistry that allows them to not only survive, but use poisonous gasses and chemicals to gain energy. 

Why, why, why are Archaea not present in the basalt layer? What kind of genetic advantage do bacteria have that allow them to live so deep? Is it possible that the Archaea simply were not detected? The authors do include a hypothesis that the bacteria migrated from oil reserves. But is it reasonable that bacteria would go from a very high hydrocarbon environment to a very sparse hydrocarbon environment? Why would Archaea not be capable of making the same evolutionary step? 

Understanding the evolution of microscopic single celled life on earth is important because it holds the spot at the root of our tree of life. You could also imagine that better understanding the conditions that these critters live and evolve under will be helpful when we investigate other planets, like Mars and Europa, for life. And that is exciting. I think there are some big holes in this particular story that are open to the researcher community. It will be interesting following this story over the next few years.

Wobble in the Goldylocks Zone

Last week I talked a little about why I thought the new planet in the Goldylocks zone around Gliese 581 had a pretty high bogus factor. Since then I have been trying to rationalize it and came up with this figure. It shows the basic method for deconvolving a signal to resolve the wobble due to a planet. The dark blue line is something like what they would measure - in this case it is the sum of the other lines, each of which is the component of motion that each individual planet would apply on the star. The blue line shows that the star is moved as much as a few thousand meters several times a year as the planets circling it tug it around and also that the planets which circle it with different periods tend to cause perterbations in the star's motions. 

By modeling the effect of various mass planets at different distances (and thus periods), scientists can strip away the modeled value and use the residuals to calculate the size of the next smallest planet. I made the largest planet the red line, which has the most influence on the star. Much like Jupiter here in our solar system, it dominates the star's motion and likewise, small errors in the red line are probably just as significant as the total influence of smaller planets (like that grey line). 

The blue line actually includes the influence of 7 planets here, but the fact is that after I plotted the third planet, you couldn't even see the influence of any of the smaller planets. The Goldylocks planet Gliese 581g pulls at Gliese as much as 1 m, which is durn close to the precision of the technique they are using to measure relative velocity. Also note, that in this little model I have here, the largest influence moves the star by as much as 10,000. That means that the technique, including the modelling component, needs to be accurate and precise to one part in 10,000. While this level of accuracy is not unheard of, especially in the physics world, it would not surprise me if the planet is discovered to be a rounding error sometime in the next decade.

Announcement on Gliese 581g; amazing, probably untrue

Buzz About Gliese 581g: Doubts of Its Existence; Aliens Signals Detected | Universe Today

www.universetoday.com

Ever since the announcement of the discovery of exoplanet Gliese 581g, there has been a buzz in the news, on websites, Twitter – pretty much everywhere

This is a space science nut's favorite story in years. A new planet found in the Goldylocks zone in a different solar system. Why not expect it? 

It would not surprise me if in fact there is not one orbiting Gliese but that the nearest three dwarf stars did, just taking into account irony and error associated with the kind of assumptions that are made in this study. 

Interesting fact of the day: when visiting the Keck telescopes in Hawaii, the astronomers hosting our group tell me that the infrared interferometry method they use to make these planet-finding observations are precise enough to detect a star's motion as small as one yard.