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December 13, 2010

what is life

with the discovery of the arscenic eating bacteria found in Californias Mono Lake, the question now asked by scientists is what exactly is life? "We don't have a very good definition of life," said researcher Christopher Voigt of the University of California, San Francisco, who works on synthetic biology. "It's a very abstract thing, what we call life, and at what point we say something doesn't have the necessary components versus it does, it just becomes way too murky." Aristotle was the first to "define" life and concluded that life was something that grows and maintains itself. In 1944, Austrian physicist Erwin Schrödinger defined life as that which resists decaying to disorder and equilibrium. But as with most definitions of life their was a loophole. Some have theorized that life is something that which can reproduce itself. Others have said that life can take in energy to move or grow, and release waste. But with so many loopholes it has been hard to nail down a concrete definition of life. "Life, because it is such a complex system of things with so many interacting parts, each of which is essential, it's really tough to make a definition," said biochemist David Deamer of the University of California, Santa Cruz.
"The practical approach to the search for life is to determine what life needs," wrote astrobiologist Chris McKay of NASA's Ames Research Center. That is where the recent arsenic finding comes into play. This discovery opens up the field of new habitats that could hold life. Whether or not this discovery holds weight over time, it's possible that some of scientists' basic assumptions about what life is and what it requires to survive will need to be revised.
Moskowitz, Clara. "Life's Great Mystery: What, Exactly, Is Life? - Technology & Science - Science - LiveScience - Msnbc.com." Breaking News, Weather, Business, Health, Entertainment, Sports, Politics, Travel, Science, Technology, Local, US & World News- Msnbc.com. 12 Dec. 2010. Web. 13 Dec. 2010. .

Posted by joshscha at 03:36 AM | Comments (3)

December 12, 2010

Astronomers Detect First Carbon Rich Exoplanet

WASP-12b, an exoplanet located around 1200 light years away from the Earth, has an atmosphere enriched in carbon. This may not seem to be a huge deal, however, it is very important finding. Although this finding does not make us more inclined to think that it is habitable because it is so far away, astronomers believe that this discovery can teach them about the interiors of these carbon-rich, rocky terrestrial planets. What I found really interesting was that it is a "very hot jupiter," meaning it is a gaseous planet, however, it is extremely hot even though it is extremely far relative to the Sun. This new discovery will allow scientists to continue their studies on exoplanet atmospheres, and to see how their atmospheres have evolved over the last 4.4 billion years that our galaxy has existed. This new discovery can also allow us to see what type of life forms possibly exist there with immense amount of organic compounds. Read the article below for more information!

URL: http://www.sciencedaily.com/releases/2010/12/101208132212.htm

Posted by katzbra at 09:57 PM | Comments (3)

New Extrasolar Planet

A new carbon rich extrasolar planet has been found using the Spitzer Space Telescope. This planet may be able to support life having equal parts of carbon and oxygen in its atmosphere and possibly having water on its surface. Astronomers are hopeful that simple life may exist on the planet, but considering the high concentration of carbon monoxide in the atmosphere, astronomers must temper their expectations. With new knowledge about arsenic-based life on earth, astronomers have found new hope for life.
We can make very accurate temperature estimates of this planet because its daytime side faces earth just before the planet passes behind its host star. This luxury allows astronomers to gain a much better understanding of climate change on the planet and how the climate may affect possible life. There are many more interesting things to consider regarding this extrasolar planet. For one, this planet appears to possess a diamond-based core, making it a very dense planet. This makes me wonder that if humans were ever able to reach this planet that is light years away, would people be interested in capitalizing on this valuable natural resource? In my opinion, business tycoons would be itching to utilize this rich natural resource if drilling could be done to reach it. Another interesting thing to note about this planet is its great size compared to its host star. This planet is huge and is also found close in proximity to its host star. Astronomers do not see planets this large forming near the sun in our solar system. Astrobiologists and other astronomers have reason to be intrigued by this distant planet. For more information, visit the link that I have provided.

http://www.abc.net.au/science/articles/2010/12/09/3085997.htm

Posted by nvohra at 09:23 PM | Comments (3)

New study shows earthly gold came from 'alien' bombardment

Researchers from the University of Maryland, College Park, the Southwest Research Institute in San Antonio, Texas, the Massachusetts Institute of Technology in Cambridge, and the Scripps Institution of Oceanography in San Diego, California have come to a common ground for an explanation on why we have iron-loving elements, such as gold, platinum, and palladium on earth. While studying other planets will iron cores (Earth has an iron core), the researchers found that iron-loving elements should be pulled to the planet's core during planetary formation so essentially, none of these iron-loving elements should be in the crust of the planet.

Since Earth has a decent amount of these iron-loving elements in the crust, scientist have been searching for reasons as to why that occurred. Scientists suggested that something must have happened to bring new iron-loving elements to Earth after completion of the separation of the metallic core and silicate mantle. They concluded that these elements were brought to Earth by impacts during the final phase of planet formation in our solar system. The scientists then used models to see what sized objects would meet the criteria.

They concluded that the largest Earth impactor was 1,500 to 2,000 miles (2,400 to 3,200 kilometers) in diameter, while those hitting the Moon were only 150 to 200 miles (250 to 300 km) across. Notice that the size of the impactors that were hitting the Earth are roughly the size of Pluto.

http://www.astronomy.com/en/News-Observing/News/2010/12/New%20study%20shows%20earthly%20gold%20came%20from%20alien%20bombardment.aspx


Posted by kalajk at 03:28 PM | Comments (3)

December 10, 2010

New method of finding the universe's first light

Astronomers are looking back to the earliest times of the solar system, to figure out when and how the first stars formed. The epoch in question is officially named “reionization epoch”.

Astronomers hope they will have their questions answered by radio waves.

So far, MIT astronomers Judd Bowman and Alan Rogers built a custom antenna, which they aimed to look for hydrogen gas between galaxies, which would have emitted a characteristic radio signal. Next, the researchers looked for evidence showing how this radio signal may have changed over time. Their experiment, which was constrained for a ‘short-term basis’, did not detect any change in the signal, which means it is likely that it took longer than 3-12 million years for galaxies and stars to form.

Their observations fit with most models of the early-universe, though the astronomers claim that the study does rule out some fringe theories.

The researchers plan to refine the instrument design, which will allow them to be able to look at a wider range of radio frequencies.

http://www.msnbc.msn.com/id/40572599/ns/technology_and_science-space/

Posted by dkaknjo at 12:03 PM | Comments (2)

December 08, 2010

Pulsating Star Mystery Solved in Rare Alignment of Cepheid Variable and Another Star

This discovery is the first double star to be observed. Not only is this an amazing observation but also this has proven the stellar pulsation theory to be correct. This can lead to Cepheids (pulsating stars) to have more knowledge known about them and furthering the information known about our universe. The article below show the details of the mystery of this double star and the new discoveries that are being made about this.


http://www.sciencedaily.com/releases/2010/11/101124143405.htm

Posted by littj at 01:11 PM | Comments (0)

NASA's new arseninc life study flawed?

Just days after the announcement in a NASA press conference about arsenic-backbones in DNA for bacteria found in Mono Lake, experts in the field are disputing the results. See this Slate article.

Briefly, the article quotes other scientists who have noted problems with the methods used by the NASA scientists. For example, the fed the bacteria salt. The problem: the salt contained trace amounts of phosphorous. So maybe the bacteria found a way to extract that phosphorous more efficiently. Second, they did not test whether the DNA was indeed made of arsenic or whether the arsenic simply clung to tghe normal phosphorous-laden backbone. Finally, the use water in the DNA extraction process, which should have broken the DNA into tiny pieces. But instead, the DNA extraction showed it to be in normal phosphate-sized chunks (which are larger).

We can expect answers to these scientific concerns very soon.

This is real science in action and it is a great example of how the peer-review process can work. Even if the reviewers who accepted the published journal article did not do a thorough job (and I am no expert to make this judgement), the scientific field will put these results to the test.

Posted by christoq at 10:25 AM | Comments (4)

December 07, 2010

Hopping Around Mars?

Scientists in the UK are working on a concept for a Mars rover different than anything we've seen so far. Essentially, this rover would be able to make short "hops" from location to location on Mars, covering distances of about one kilometer. Perhaps one of the most promising aspects of the rover would be its efficiency. It would not require fuel because in between jumps, it would compress gas while running on a special battery that would last years instead of weeks and allow the rover to explore hundreds of locations. Some of the prime objectives of the rover would be to explore evidence for past life by visiting many and varying locations, but also to look into the possibility of using existing materials for processing future space nuclear systems with basic manufacturing techniques.

A video of the concept can be found here: http://www.youtube.com/watch?v=grffBimdwUg

And the article itself can be found here: http://www.sciencedaily.com/releases/2010/11/101118084046.htm

Posted by dankeith at 10:11 PM | Comments (6)

December 05, 2010

Copying is not blogging

Just a reminder to all Astro 101 students who are trying to get the extra credit. The instructions for posting (on cTools here and on the Astro 101 blog itself) state that your posts/comments must be your own. Posts that are simply cut/pastes of a published article will not be counted.

Posted by christoq at 09:47 PM | Comments (0)

Jupiter's Little Red Spot

Scientists have been observing a massive anticyclone on Jupiter known as the Little Red Spot and from their measurements they believe that winds speeds in the Little Red Spot can reach 384 MPH. Scientists have concluded that the Little Red Spot is actually three separate storms that have combined to form one massive storm with winds rotating counter-clockwise. Although the Little Red Spot is not as big as The Big Red Spot, it is still larger than the Earth and it's getting bigger.

Check out the link if you want to see a video.
http://www.sciencedaily.com/videos/2008/1108-jupiters_little_red_spot.htm

Posted by msapick at 09:46 PM | Comments (9)

Dark Matter Could Transfer Energy in the Sun

Researchers from the Institute for Corpuscular Physics (IFIC) and other European groups have studied the effects of the presence of dark matter in the Sun. According to their calculations, low mass dark matter particles could be transferring energy from the core to the external parts of the Sun, which would affect the quantity of neutrinos that reach the Earth.

"We assume that the dark matter particles interact weakly with the Sun's atoms, and what we have done is calculate at what level these interactions can occur, in order to better describe the structure and evolution of the Sun", Marco Taoso, researcher at the IFIC, a combined centre of the Spanish National Research Council and the University of Valencia, explains to SINC.

The astrophysical observations suggest that our galaxy is situated in a halo of dark matter particles. According to the models, some of these particles, the WIMPs (Weakly Interacting Massive Particles) interact weakly with other normal ones, such as atoms, and could be building up on the inside of stars. The study, recently published in the journal Physical Review D, carries out an in-depth study of the case of the Sun in particular.

"When the WIMPs pass through the Sun they can break up the atoms of our star and lose energy. This prevents them from escaping the gravitational force of the Sun which captures them, and they become trapped, orbiting inside it, with no way of escaping", the researcher points out.
The dark matter cools down the Sun's core

Scientists believe that the majority of the dark matter particles gather together in the centre of the Sun, but in their elliptic orbits they also travel to the outer part, interacting and exchanging with the solar atoms. In this way, the WIMPs transport the energy from the burning central core to the cooler peripheral parts.

"This effect produces a cooling down of the core, the region from where the neutrinos originate due to the nuclear reactions of the Sun", Taoso points out. "And this corresponds to a reduction in the flux of solar neutrinos, since these depend greatly on the temperature of the core".

The neutrinos that reach the Earth can be measured by means of different techniques. These data can be used to detect the modifications of the solar temperature caused by the WIMPs. The transport of energy by these particles depends on the likelihood of them interacting with the atoms, and the "size" of these interactions is related to the reduction in the neutrino flux.

"As a result, current data about solar neutrinos can be used to put limits on the extent of the interactions between dark matter and atoms, and using numerical codes we have proved that certain values correspond to a reduction in the flux of solar neutrinos and clash with the measurements", the scientist reveals.

The team has applied their calculations to better understand the effects of low mass dark matter particles (between 4 and 10 gigaelectronvolts). At this level we find models that attempt to explain the results of experiments such as DAMA (beneath an Italian mountain) or CoGent (in a mine in the USA), which look for dark material using "scintillators" or WIMP detectors.
Debate about WIMP and solar composition

This year another study by scientists from Oxford University (United Kingdom) also appeared. It states that WIMPs not only reduce the fluxes of solar neutrinos, but also, furthermore, modify the structure of the Sun and can explain its composition.

"Our calculations, however, show that the modifications of the star's structure are too small to support this claim and that the WIMPs cannot explain the problem of the composition of the sun", Taoso concludes.

Provided by FECYT - Spanish Foundation for Science and Technology

More information and pictures can be found at:
http://www.physorg.com/news/2010-12-dark-energy-sun.html

Posted by pjgarret at 02:28 PM | Comments (0)

December 04, 2010

Alien Life, the GAFJ-1 Bacteria

When life gives you arsenic, make DNA
By Emily Staudenmaier

Science bloggers were atwitter this week following NASA’s announcement on Monday that a press conference would be held to discuss an “astrobiology finding that will impact the search for evidence of extraterrestrial life.” The rather cryptic press release led to rumors that perhaps NASA had discovered evidence of life on another planet.

Thursday's press conference dispelled those rumors. Instead, NASA announced that a team headed by astrobiology researcher Felisa Wolfe-Simon had discovered a remarkable new microorganism, GFAJ-1, in California's highly toxic Mono Lake.

GFAJ-1, the researchers report in a paper in Science (it's behind a paywall, unfortunately), is capable of using arsenic instead of phosphorus as one of its basic building blocks when grown in an environment abundant with the former but lacking the latter. Biologists have never before encountered an organism like this.

NASA’s press conference seems to have underwhelmed some of the bloggers and reporters who had endured days of excited speculation. Hoping to hear about the discovery of an alien life form, they felt ripped off that all NASA had on offer was a new microbe from a lake in California (xkcd captured the researchers' side of this rather hilariously).

Well, they should be excited. The fact that NASA didn’t stumble upon ALF and ET having a tea party in some distant corner of the universe does not make the implications raised by the abilities of GFAJ-1 any less profound (though, to be fair, the ALF/ET announcement would have been pretty cool).

GAFJ-1 is the ultimate optimist — instead of making lemonade from lemons, it makes DNA from arsenic. It not only can survive in the arsenic, it incorporates the normally poisonous element into all of its biomolecular structures — an adaptive strategy that is unprecedented anywhere else in the field of physiology.

The ability of GAFJ-1 to use arsenic instead of phosphorus in its DNA, proteins, and lipids will, at the bare minimum, cause biology textbooks to be rewritten.

Every such textbook notes that six elements (carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus) serve as the building blocks of life. Imagine that these elements are Legos that are capable of combining to form neat, stable, and functional structures. Replacing phosphorus with arsenic is like trying to build something out of both Legos and K'NEX — the two pieces don’t normally fit stably together. And yet this microbe provides living proof that it is possible to live and grow with DNA that, in effect, has a backbone made of K'NEX and a body made out of Legos.

This broadening of the bounds of what is physiologically possible for life forms on Earth also rewrites the search for life elsewhere. Since the mechanisms common on Earth are no longer the only game in town, a wider set of elements will now be considered capable of sustaining life.

There could be a more immediate scientific impact as well. In the past, understanding how microbes are able to survive under extreme conditions has changed the way we do research, as well as the way we practice industrial science and medicine. For example, the bacteria Thermus aquaticus lives in hot springs and can withstand great heat, which makes one of its enzymes a perfect reagent for certain molecular biology techniques that must be done at high temperatures. Understanding the molecular and physiological capabilities of this bacteria led to a revolution in research. Studying GAFJ-1 in a similarly thorough manner could yield huge practical results.

The exact mechanisms that allow GAFJ-1 to survive and the evolutionary forces which led to the development of these mechanisms remain to be seen, but there’s no doubt that new information about this organism will continue to alter, on a very fundamental level, how we think about biology.

And that, I would argue, is just as cool as extraterrestrial aliens.

Emily Staudenmaier is a Neurobiology Research Assistant and Laboratory Manager at Brandeis University. She has a B.A. in Molecular Biology from Kenyon College.

http://www.boston.com/bostonglobe/editorial_opinion/blogs/the_angle/2010/12/when_life_gives.html

Posted by mbowang at 01:49 PM | Comments (5)

December 03, 2010

Dwarf Stars in Other Galaxies

A new estimate for stars in the universe has been created to include "dwarf stars", or stars that are cool and dim. The problem is that although astronomers know these stars exist, they are too dim to be seen and counted. So instead of counting them individually they count what they expect to find based on the light data they can collect. This new system has as much as tripled the estimation for how many stars we have in our universe. Also, this data shows that other galaxies may have way more stars than out galaxy. This shows that the Milky Way might be considerably different than the other galaxies around it.


How Many Stars? Three Times as Many as We Thought, Report Says

New York Times December 2 2010 A19

Scientists said Wednesday that the number of stars in the universe had been seriously undercounted, and they estimated that there could be three times as many stars out there as had been thought.

This undercounting, of cool, dim dwarf stars in certain galaxies, could throw a monkey wrench into astronomers’ understanding of how galaxies formed and grew over the eons.

“It’s very problematic,” said Pieter van Dokkum, a professor of astronomy at Yale who reported the findings in the journal Nature with Charlie Conroy of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

The conundrum is that astronomers cannot actually count the dwarf stars, which have masses less than a third of that of the Sun, in galaxies outside the Milky Way. So instead, they counted the brighter Sun-like stars and assumed that there were about 100 unseen dwarfs for each larger Sun-like star, as is the case in the Milky Way.

Yet not every galaxy looks like the Milky Way, with its spiraling pinwheel arms. Some are blobby and elliptical, and it was an untested assumption that the distribution of star sizes in elliptical galaxies is the same as in the Milky Way.

Dr. van Dokkum and Dr. Conroy took an innovative approach to counting what they could not see. Because the dwarfs are cooler, the fingerprint of certain colors they emit and absorb is different from that of larger stars. Thus, while they could not see individual stars, the astronomers could calculate the number of dwarfs required to produce the telltale color fingerprint they detected in the light coming from the whole galaxy.

And they found that in eight elliptical galaxies, the ratio of dwarf stars to Sun-like stars was 1,000 or 2,000 to 1, rather than the 100 to 1 in the Milky Way. A typical elliptical galaxy, thought to consist of about 100 billion stars, would have one trillion or more stars. Ellipticals account for about a third of all galaxies, leading to the new estimate of at least three times as many stars over all.

“We may have to abandon this notion of using the Milky Way as a template for the rest of the universe,” Dr. van Dokkum said. If the findings are correct, an undercount of dwarfs would mean astronomers have underestimated the masses of galaxies, and that would mean that galaxies developed earlier and faster than currently thought.

“Which would be very interesting, actually,” said Richard Ellis, a professor of astronomy at the California Institute of Technology who was not involved in the research. “It’s very important that papers like this are published so that we are reminded how fragile our knowledge of the universe is.”

Yet Dr. Ellis said he remained skeptical. “It’s good data and it’s a sound analysis,” he said, “but there are a few escape clauses.”

For one, the research assumes that the stars in an elliptical galaxy are made of exactly the same stuff as those in spiral galaxies, an assumption that cannot be tested yet.

Also inconclusive: whether we now have three times as many wishes.


http://www.nytimes.com/2010/12/02/science/space/02star.html?_r=1&scp=2&sq=astronomy&st=cse

Posted by rosiel at 05:23 PM | Comments (5)

Hot Spots on Saturn Moon

Readings from the space orbiter Cassini provide evidence that there is in fact warmth coming up through the icy cracks of Enceladus, one of Saturn's moons. Images taken from an infared spectrometer reveal that the heated lines, which they refer to as "tiger stripes" are some 245 degrees warmer than some of the coldest areas on the moon. Most of the attention in the article was focused on a particular fissure known as Damascus Sulcus, showing that its temperatures varied even within the warm trench. This evidence further supports the belief that this moon could have subsurface oceans.

Full article (with images of the stripes) available here: http://cosmiclog.msnbc.msn.com/_news/2010/11/30/5555919-see-whats-hot-on-saturn-moon

Posted by devdrake at 01:11 PM | Comments (3)

December 02, 2010

New Form of Life Changes What We Look for in the Search for Life

Second Genesis on Earth?
By Marc Kaufman
Washington Post Staff Writer
Retrieved from
Thursday, December 2, 2010; 2:55 PM

All life on Earth - from microbes to elephants and us - is based on a single genetic model that requires the element phosphorus as one of its six essential components.

But now researchers have uncovered a bacterium that has five of those essential elements but has, in effect, replaced phosphorus with its look-alike but toxic cousin arsenic.

News of the discovery caused a scientific commotion, including calls to NASA from the White House and Congress asking whether a second line of earthly life has been found.

A NASA press conference Thursday and an accompanying article in the journal Science, gave the answer: No, the discovery does not prove the existence of a "second genesis" on Earth. But the discovery very much opens the door to that possibility and to the related existence of a theorized "shadow biosphere" on Earth - life evolved from a different common ancestor than all that we've known so far.

"Our findings are a reminder that life-as-we-know-it could be much more flexible than we generally assume or can imagine," said Felisa Wolfe-Simon, the young biochemist who led the effort after being selected as a NASA Astrobiology Research Fellow and as a member of the National Astrobiology Institute team at Arizona State University.

"If something here on Earth can do something so unexpected - that breaks the unity of biochemistry - what else can life do that we haven't seen yet?" she said.

The research, funded through NASA and conducted with samples from California's Mono Lake, found that some of the bacteria not only used arsenic to live, but had arsenic embedded into their DNA, RNA and other basic underpinnings.

"This is different from anything we've seen before," said Mary Voytek, senior scientist for NASA's program in astrobiology , the arm of the agency involved specifically in the search for life beyond Earth and for how life began here.

"These bugs haven't just replaced one useful element with another, they have the arsenic in the basic building blocks of their makeup," she said. "We don't know if the arsenic replaced phosphorus or if it was there from the very beginning - in which case it would strongly suggest the existence of a shadow biosphere."

Theoretical physicist and cosmologist Paul Davies, director of the Beyond Center at Arizona State and a prolific writer, is a co-author on the paper. He had been thinking about the idea for a decade and had written a paper in 2005. So had University of Colorado at Boulder philosopher and astrobiologist Carol Cleland. Both asked why nobody was looking for life with different origins on Earth, and Cleland coined the phrase "shadow biosphere."

At a Beyond Center conference four years ago, Wolfe-Simon, then in her late 20s, proposed a way to search for a possible shadow biosphere, and it involved Mono Lake and its arsenic.

"We were kicking vague ideas around, but she had a very specific proposal and then went out and executed it," Davies said. "It defies logic to think she found the only example of this kind of unusual life. Quite clearly, this is the tip of a huge iceberg."

All life as we know it contains six essential elements - carbon, oxygen, hydrogen, nitrogen, sulfur and phosphorus - that have qualities that make them seemingly ideal for their tasks. A form of phosphorus, for instance, is near perfect for building the framework for the DNA molecule, and another form is crucial to the transfer of energy within cells.

These forms of phosphorus are well suited for their job because they are especially stable in the presence of water. Arsenic is not, and that fact is one that raises concerns for some researchers familiar with the Mono Lake bugs.

Chemist Steven Benner of the Foundation for Applied Molecular Evolution in Florida has been involved in "shadow biosphere" research for several years, and will speak at the NASA unveiling of Wolfe-Simon's work. He says that the Mono Lake results are intriguing - "I do not see any simple explanation for the reported results that is broadly consistent with other information well known to chemistry" - but he says they are not yet proven. And a primary reason why is that arsenic compounds break down quickly in water while phosphorus compounds do not.

His conclusion: "It remains to be established that this bacterium uses arsenate as a replacement for phosphate in its DNA or in any other biomolecule."

Nonetheless, the paper and its results have created an excitement reminiscent of the 1995 announcement at NASA headquarters of the discovery of apparent signs of ancient life in a meteorite from Mars found in Antarctica. That finding was central to establishing the field of astrobiology, but was also broadly challenged and a scientific consensus evolved that the case for signs of life in the meteorite had not been proven.

The Mono Lake discovery highlights one of the central challenges of astrobiology - knowing what to look for in terms of extraterrestrial life. While it remains uncertain whether the lake's microbes represent another line of life, they show that organisms can have a chemical architecture different from what is currently understood to be possible.

"One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should 'follow the elements,' " said Ariel Anbar, an ASU professor and biogeochemist. "Felisa's study teaches us that we ought to think harder about which elements to follow."

Mono Lake was selected as a work site by Wolfe-Simon because it is highly unusual and had been well studied by other scientists trying to answer different questions.

The lake receives run-off from the Sierra Nevada mountains, which have relatively high concentrations of arsenic. When the water arrives at Mono Lake, it has nowhere to go because there are no rivers carrying water further downstream. That means the arsenic, and other elements and compounds, can concentrate to unusally high levels. Arsenic is present in Mono Lake at a concentration 700 times greater than what the EPA considers safe.

Wolfe-Simon was invited to use the Menlo Park, Calif., lab of the U.S. Geological Survey and was aided in her work by senior research scientist Ron Oremland, who has studied arsenic in Mono Lake for decades. The initial work was quite simple: She took mud from the briny as well as toxic lake into the lab and began growing bacteria in Petri dishes. She gradually replaced phosphate salt with arsenic until the surviving bacteria could grow without needing the phosphates at all.

The bugs, an otherwise common bacteria in the halomonadaceae family, thrived without phosphates and with lots of arsenic. She then determined that the arsenic was embedded in the core genetic and energy transfer systems of the bacteria - that it appeared to have replaced (or preceeded) the phosphorus.

As she explained, replacing phosphorus with arsenic may seem suicidal, but the two are very similar in their makeup. Arsenic is considered toxic because most living things take it in and treat it like phosphorus, only to be destroyed by the small differences.

She said that while small amounts of the phosphorus remained in the arsenic-based bugs, she was able to determine that it was definitely not enough to supply the presumed phosphorus needs of the cell. That, she said, was being done with the arsenic.

"Sometimes I'm asked why something like this has never been found before, and the answer is that nobody has run the experiment before," Wolfe-Simon said. "There was nothing really complicated about it - I asked a simple question that was testable and got an answer."

Wolfe-Simon said she hopes to further test her findings in northern Argentina, where, she's been told, some microbes can not only tolerate arsenic, but absolutely need arsenic to survive.

Posted by lebeisma at 02:59 PM | Comments (5)

Astronomers analyze atmosphere of "Super-Earth" planet 40 lightyears away

http://www.scientificamerican.com/article.cfm?id=gj-1214-transit

Astronomers have furthered their search for an extrasolar planet that could potentially resemble Earth.

They are able to study the planets whose path takes them in front of the host star. This allows the starlight to filter through, allowing us from our perspective on Earth, to view the atmosphere.

This most recent alignment allowed us to study GJ 1214 b, a planet about 40 light-years away. It was found through spectral analysis that the planet has low absorption, meaning the planet either has a hydrogen atmosphere with high cloud cover, or it has a dense water vapor atmosphere which tightly hugs the planet.

While GJ 1214 b doesn't appear to be habitable, NASA plans to launch the James Webb Space Telescope in 2015 which could potentially scan extrasolar atmospheres for signs of life.

Posted by nealroth at 10:42 AM | Comments (2)