Posted on by Ryan Anderson

Europa Analog Deep-Sea Vents Discovered in the Caribbean

A team recovers the hybrid robotic vehicle Nereus aboard the research vessel Cape Hatteras during a partially NASA-funded expedition to the Mid-Cayman Rise in October 2009. A search for new hydrothermal vent sites along the 110-kilometer-long ridge, the expedition featured the first use of Nereus in "autonomous," or free-swimming, mode. Image credit: Woods Hole Oceanographic Institution

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White sand, blue water, sunny skies, pina coladas. When you think of “extreme environments” I doubt the Caribbean is high on your list. But a team of scientists from Woods Hole Oceanographic institute and NASA’s Jet Propulsion Laboratory, exploring the 68-mile-long Mid-Cayman rise deep beneath the surface of the Caribbean, have discovered the deepest known hydrothermal vent in the world, along with two other distinct types of vents.

The mid-Cayman rise is a much smaller version of the mid-ocean ridge system, a chain of submarine mountains that encircles the globe. These ridges form in locations where tectonic plates are pulling apart, allowing mantle rocks to melt and emerge at the surface as lava. Seawater, percolating through the hot rocks at these spreading centers, is superheated and emerges at vents, bearing a rich bounty of dissolved nutrients to support thriving ecosystems that can live without any sunlight.

“This was probably the highest-risk expedition I have ever undertaken,” said chief scientist Chris German, a Woods Hole Oceanographic Institution geochemist who has pioneered the use of autonomous underwater vehicles to search for hydrothermal vent sites. “We know hydrothermal vents appear along ridges approximately every 100 kilometers [62 miles]. But this ridge crest is only 100 kilometers long, so we should only have expected to find evidence for one site at most. So finding evidence for three sites was quite unexpected – but then finding out that our data indicated that each site represents a different style of venting – one of every kind known, all in pretty much the same place – was extraordinarily cool.”

Towering carbonate formations at the Lost City hydrothermal field. Image Credit: Kelley, U of Washington, IFE, URI-IAO, NOAA

In addition to the deepest hydrothermal vent yet discovered, at a depth of 5,000 meters (16,400 feet), the team also found a shallower low-temperature vent. Only one other vent of this type has been discovered: the famous “Lost City” vent in the Atlantic.

“We were particularly excited to find compelling evidence for high-temperature venting at almost 5,000 meters depth,” said Julie Huber, a scientist in the Josephine Bay Paul Center at the Marine Biological Laboratory in Woods Hole. “We have absolutely zero microbial data from high-temperature vents at this depth.”

The ecosystems encrusting the deep sea vents on the mid-Cayman rise provide valuable clues to how life could arise and thrive elsewhere in the solar system. “Most life on Earth is sustained by food chains that begin with sunlight as their energy source. That’s not an option for possible life deep in the ocean of Jupiter’s icy moon Europa,” said JPL co-author Max Coleman.

With an airless sky, intense radiation, icy crust, and no pina coladas, the surface of Europa is about as different from the Caribbean as you can get. But deep on the sea floor, they may be remarkably similar.

“Organisms around the deep vents get energy from the chemicals in hydrothermal fluid, a scenario we think is similar to the seafloor of Europa,” Coleman said. “This work will help us understand what we might find when we search for life there.”

An artist's depiction of a future Europa mission. Image credit: NASA
Posted on by Steve Nerlich

Astronomy Without A Telescope – Animal Astronomy

Avian astronomers at work. Credit: abc.net.au.

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In the 1950s, the Sauer research team locked some birds in Olbers planetarium and started messing with them. First they projected a northern hemisphere autumn sky and the birds flew ‘south’ – away from Polaris and keeping Betelgeuse to the left (‘east’). Then they projected a spring night sky and the birds flew ‘north’ towards Polaris with Betelgeuse again to their left, albeit this time in the ‘west’. The position of Betelgeuse appeared to be significant, perhaps because it’s one of the brighter stars in the northern hemisphere and just to the north of the celestial equator.

Later experiments with Indigo Buntings demonstrated that birds raised with no experience of the night sky didn’t have a clue what to do when released into a planetarium. However, birds that were raised with the night sky visible would fly ‘south’ away from the sky’s axis of rotation, whether that was Polaris or an artificial arbitrary axis created within the planetarium.

From this work, researchers concluded that it was unlikely that birds were born with a genetic star map, but instead learned to orientate themselves with respect to the rotating night sky by reference to other directional cues – like the position of the Sun and the Earth’s magnetic field.

It’s thought that many migratory birds closely monitor sunrise and sunset – allegedly when you see a line of birds on a power line, most will be facing east in the morning and west in the evening, recalibrating their internal compasses. Checking for a north-south plane of polarized light at sunrise and sunset may help them determine their latitude – by indicating how far off due east or west the Sun is when it’s at the horizon.

Pigeons have well developed magnetoreception that they can use as an alternative to solar navigation. For example, they can ‘home’ even with a heavily overcast sky – but get them to wear a little magnetized helmet that screws up their perception of the Earth’s magnetic field and they get lost. On the other hand, if it’s a clear day with the Sun visible they can find home just fine – even with a little magnetized helmet on.

As well as the birds – bacteria, bees, termites, lobsters, salamanders, salmon, turtles, mole rats and bats have all been shown to possess magnetoreception.

Magnetotactic bacteria manufacture their own magnetite crystals – building chains of crystals that mimic a compass needle. The bacteria appear to use their magnetite crystals for the simple purpose of determining which way is down – since a straight line to magnetic north will pass through the Earth’s surface.

Magnetospirillum with a line of synthesized magnetite crystals visible. Credit: www.microbiologybytes.com

It’s yet to be determined how a complex nervous system might interface with magnetite or whether magnetite is the primary mechanism in larger multicellular animals. Magnetite crystals have been isolated from bees and termites – and are apparently synthesized by them. However, in larger animals it’s harder to tell – as these crystals are tiny and difficult to find or visualize in vivo. An alternate magnetoreception mechanism based on photochemicals in the retina has been proposed for migratory birds – although a role for magnetite, particularly in pigeons which have relatively large concentrations of it in their beaks, can’t be ruled out.

Humans have traces of magnetite in their brains – although the court is still out on whether this gives us any capacity for direction finding by magnetoreception. Some research suggests a few individuals may have some very minor ability – but not enough for anyone to consider preferring this to their GPS.

Posted on by Nancy Atkinson

Zapping Titan-Like Atmosphere with UV Creates Life Precursors

Which Planets Have Rings?
This colorized image taken by the Cassini orbiter, shows Saturn's A and F rings, the small moon Epimetheus and Titan, the planet's largest moon. Credit: NASA/JPL/Space Science Institute

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From the University of Arizona

The first experimental evidence showing how atmospheric nitrogen can be incorporated into organic macromolecules is being reported by a University of Arizona team. The finding indicates what organic molecules might be found on Titan, the moon of Saturn that scientists think is a model for the chemistry of pre-life Earth.

Earth and Titan are the only known planetary-sized bodies that have thick, predominantly nitrogen atmospheres, said Hiroshi Imanaka, who conducted the research while a member of UA’s chemistry and biochemistry department.

How complex organic molecules become nitrogenated in settings like early Earth or Titan’s atmosphere is a big mystery, Imanaka said.

“Titan is so interesting because its nitrogen-dominated atmosphere and organic chemistry might give us a clue to the origin of life on our Earth,” said Imanaka, now an assistant research scientist in the UA’s Lunar and Planetary Laboratory. “Nitrogen is an essential element of life.”

However, not just any nitrogen will do. Nitrogen gas must be converted to a more chemically active form of nitrogen that can drive the reactions that form the basis of biological systems.

Imanaka and Mark Smith converted a nitrogen-methane gas mixture similar to Titan’s atmosphere into a collection of nitrogen-containing organic molecules by irradiating the gas with high-energy UV rays. The laboratory set-up was designed to mimic how solar radiation affects Titan’s atmosphere.

Most of the nitrogen moved directly into solid compounds, rather than gaseous ones, said Smith, a UA professor and head of chemistry and biochemistry. Previous models predicted the nitrogen would move from gaseous compounds to solid ones in a lengthier stepwise process.

Titan looks orange in color because a smog of organic molecules envelops the planet. The particles in the smog will eventually settle down to the surface and may be exposed to conditions that could create life, said Imanaka, who is also a principal investigator at the SETI Institute in Mountain View, Calif.

However, scientists don’t know whether Titan’s smog particles contain nitrogen. If some of the particles are the same nitrogen-containing organic molecules the UA team created in the laboratory, conditions conducive to life are more likely, Smith said.

Laboratory observations such as these indicate what the next space missions should look for and what instruments should be developed to help in the search, Smith said.

Imanaka and Smith’s paper, “Formation of nitrogenated organic aerosols in the Titan upper atmosphere,” is scheduled for publication in the Early Online edition of the Proceedings of the National Academy of Sciences the week of June 28. NASA provided funding for the research.

The UA researchers wanted to simulate conditions in Titan’s thin upper atmosphere because results from the Cassini Mission indicated “extreme UV” radiation hitting the atmosphere created complex organic molecules.

Therefore, Imanaka and Smith used the Advanced Light Source at Lawrence Berkeley National Laboratory’s synchroton in Berkeley, Calif. to shoot high-energy UV light into a stainless steel cylinder containing nitrogen-and-methane gas held at very low pressure.

The researchers used a mass spectrometer to analyze the chemicals that resulted from the radiation.

Simple though it sounds, setting up the experimental equipment is complicated. The UV light itself must pass through a series of vacuum chambers on its way into the gas chamber.

Many researchers want to use the Advanced Light Source, so competition for time on the instrument is fierce. Imanaka and Smith were allocated one or two time slots per year, each of which was for eight hours a day for only five to 10 days.

For each time slot, Imanaka and Smith had to pack all the experimental equipment into a van, drive to Berkeley, set up the delicate equipment and launch into an intense series of experiments. They sometimes worked more than 48 hours straight to get the maximum out of their time on the Advanced Light Source. Completing all the necessary experiments took years.

It was nerve-racking, Imanaka said: “If we miss just one screw, it messes up our beam time.”

At the beginning, he only analyzed the gases from the cylinder. But he didn’t detect any nitrogen-containing organic compounds.

Imanaka and Smith thought there was something wrong in the experimental set-up, so they tweaked the system. But still no nitrogen.

“It was quite a mystery,” said Imanaka, the paper’s first author. “Where did the nitrogen go?”

Finally, the two researchers collected the bits of brown gunk that gathered on the cylinder wall and analyzed it with what Imanaka called “the most sophisticated mass spectrometer technique.”

Imanaka said, “Then I finally found the nitrogen!”

Imanaka and Smith suspect that such compounds are formed in Titan’s upper atmosphere and eventually fall to Titan’s surface. Once on the surface, they contribute to an environment that is conducive to the evolution of life.

Posted on by Jean Tate

Maybe ET’s Calling, But We Have the Wrong Phone

The search (xkcd)

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To date, SETI (Search for ExtraTerrestrial Intelligence) has focused on ETs who ‘phone home’ using the radio part of the electromagnetic spectrum, and even a very small region within that.

But what if ET’s phone doesn’t use radio waves? Sure the xkcd comic, is funny, but maybe it points to a deep flaw in our attempts to contact, or hear from, an ETI?

When Giuseppe Cocconi and Philip Morrison suggested the possibility of interstellar communication via electromagnetic waves in a 1959 paper in Nature, only radio was feasible, as we then had the ability to detect only artificial radio signals, if produced by ETIs with 1959 human technology. Since then we’ve developed the ability to detect a laser signal, brighter than the Sun (if only for a nanosecond) if it came from a source several light-years away … but lasers weren’t invented then.

What might ET’s equivalent of ants’ pheromones be?

Back in 1959 if you’d said that the Earth would, within a mere half century, started to go ‘radio quiet’, not many people would have taken you seriously. Yet that’s exactly what’s happened! Free to air (FTA) broadcasting, especially for TV, is being replaced by TV delivered over coaxial cable, optical fibers, or even the phone company’s twisted copper pairs. And where it’s continuing, as in satellite TV broadcasting, its power has dropped (today’s digital formats are more efficient than the old analog ones). Military radars, the brightest source of artificial radio waves by far, no longer broadcast in a single channel, but hop, rapidly, from frequency to frequency, to avoid jamming.

“Our improving technology is causing the Earth to become less visible,” says astronomer Frank Drake, SETI’s paterfamilias. “If we are the model for the universe, that is bad news.”

In the past half century SETI researchers have expanded the scope of their searches. Not only are far more radio channels being examined, but artificial signals in the optical are being sought too. How to decide which of the billions or trillions of possible radio channels to search? For example, the Allen Telescope Array will, when built, monitor a billion channels between 0.5 and 11 GHz – but that’s a trivial fraction of the entire radio waveband. Some ideas, however, seem cute; for example, the SETI Institute’s Gerald Harp has proposed searching at 4.462336275 gigahertz, in what’s called the PiHI range, because it’s the hydrogen atom’s emission frequency times pi. More seriously, Harvard University’s Paul Horowitz says optical SETI programs should really look at infrared frequencies “Stars are darker in the infrared and lasers are brighter and the smog goes away,” Horowitz says. Infrared allows astronomers to see into the galactic center, where dust scatters visible light.

There’s something rather ironic about SETI today; on the one hand, we recognize that our initial hopes were far too high, being based on overly simplistic assumptions; on the other, the tremendous progress in finding exoplanets has given us greater and greater certainty that Earth-like planets not only exist, but are, very likely, common. “All of astronomy has come to embrace this idea that there must be life out there,” says Harp.

So how to address the fact that we simply do not know what sorts of technologies a civilization like ours may have, a century or a millennium from now? After all, as Drake says “We are very conservative at SETI, we assume in our searches the existence of only things we ourselves have and know how to make.” Other scientists, and SETI enthusiasts, have proposed hunting in different electromagnetic realms, like gamma rays. Spacecraft that rely on nuclear fusion or antimatter-matter annihilation as a power source might produce such rays. But standard SETI strategy does not embrace such “speculative” scenarios.

SETI researchers, some say, should also contemplate what technologies supersmart aliens might possess and seek out the corresponding signals. In a 2008 arXiv paper, “Galactic Neutrino Communication“, John Learned of the University of Hawaii at Manoa suggested that ET could be sending beams of neutrinos Earth’s way. Energy requirements for such a beam make that scenario seem implausible, but not necessarily impossible. Detectors currently under construction, such as IceCube at the South Pole, could spot unexpected stray neutrinos. If a few with the same energy came from the same direction, astronomers would know something screwy was up.

In another paper, “The Cepheid Galactic Internet“, Learned suggests that ET could send a signal using a neutrino beam to deliver energy to a Cepheid variable. A Cepheid “blows up and comes crashing back down,” he says. “And the energy builds up and it blows again, like a geyser.” ET could leverage a Cepheid’s inherent instability by delivering a boost of energy that messes with the star’s schedule. Looking through existing data could reveal whether such meddling has occurred. “All that is needed is people analyzing for other reasons to do their analyses in another way,” Learned says.

Drake and most others agree that SETI’s approach should be multidirectional – let a thousand alien hunters bloom. The only ideas that don’t do anybody any good, Horowitz says, are the ones for which there is no conceivable way to look. “I’d like to keep an open mind,” he says, “but not so much that my brain falls out.”

Physicist Paul Davies of Arizona State University in Tempe, however, suggests that researchers don’t need to know what to look for. Find the fishy thing first, and then argue about its origin, he says.

As Davies has argued, maybe discovering ET does indeed depend on a thought revolution. Fifty years of signal-less searching suggests that the problem could lie not with the aliens among the stars, but with ourselves.

Maybe the sentient ants should not give up, just yet.

Sources: Science News. Cocconi and Morrison’s 1959 Nature paper (copyright Nature)

Posted on by Ryan Anderson

Ice Caves Possible on Mars

The circular black features in this 2007 figure are caves formed by the collapse of lava tubes on Mars. Image credit: NASA/JPL-Caltech/ASU/USGS

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New results published in the journal Icarus suggest that caves on Mars may provide future astronauts with more than just shelter. In many locations, even far from the poles, the caves may actually trap water ice.

Ice caves are made of rock, but they contain ice year-round. (Not to be confused with glacier caves, which are caves made of ice!) Ice caves can be found on the Earth even where surface temperatures are above freezing for months at a time. This happens because cold winter air sinks into the cave and is trapped, but during the summer, the circulation in the cave shuts off: it is full of dense cold air so the warm air outside can’t get in.

Now, in a study led by Kaj Williams of NASA Ames, scientists have used simulations of the global climate and assumptions about the thermal properties of the surface to figure out where on Mars similar cold-trapping might occur. Their results show that a significant portion of the martian surface has the right conditions for ice to accumulate in caves.

Even more tantalizing, the huge volcanic provinces of Tharsis and Elysium look to be particularly good at accumulating ice. This is important because caves formed by collapsing lava tubes have been seen on the flanks of these volcanoes. Lava tube caves on Earth tend to have limited air circulation, making them good candidates for ice accumulation.

Astronauts on the surface of Mars will likely need to take cover underground to avoid the harsh radiation environment of the surface. Natural caves such as lava tubes have been suggested as ideal ready-made shelters for astronauts, and they are only looking better. Not only could ice caves provide water as a resource, the ice could preserve valuable records of past climate cycles, and the caves may be important habitats for past or present martian life.

Williams and his team plan to continue refining their models, particularly focusing on the Tharsis and Elysium regions, using higher-resolution atmospheric models and more  precise geologic data to pinpoint areas that are best for cave-ice formation.

Ice formations in a terrestrial ice cave in Montenegro. © copyright by Jack Brauer.
Posted on by Nancy Atkinson

Alien Life on Titan? Hang on Just a Minute…

This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan. Image credit: NASA/JPL

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Two papers released last week detailing oddities found on Titan have blown the top off the ‘jumping to conclusions’ meter, and following media reports of NASA finding alien life on Saturn’s hazy moon, scientists are now trying to put a little reality back into the news. “Everyone: Calm down!” said Cassini imaging team leader Carolyn Porco on Twitter over the weekend. “It is by NO means certain that microbes are eating hydrogen on Titan. Non-bio explanations are still possible.” Porco also put out a statement on Monday saying such reports were “the unfortunate result of a knee-jerk rush to sensationalize an exciting but rather complex, nuanced and emotionally-charged issue.”

Astrobiologist Chris McKay told Universe Today that life on Titan is “certainly the most exciting, but it’s not the simplest explanation for all the data we’re seeing.”

McKay suggests everyone needs to take the Occam’s Razor approach, where the simplest theory that fits the facts of a problem is the one that should be selected.

The two papers suggest that hydrogen and acetylene are being depleted at the surface of Titan. The first paper by Darrell Strobel shows hydrogen molecules flowing down through Titan’s atmosphere and disappearing at the surface. This is a disparity between the hydrogen densities that flow down to the surface at a rate of about 10,000 trillion trillion hydrogen molecules per second, but none showing up at the surface.

“It’s as if you have a hose and you’re squirting hydrogen onto the ground, but it’s disappearing,” Strobel said. “I didn’t expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should ‘float’ to the top of the atmosphere and escape.”

The other paper (link not yet available) led by Roger Clark, a Cassini team scientist, maps hydrocarbons on Titan’s surface and finds a surprising lack of acetylene. Models of Titan’s upper atmosphere suggest a high level of acetylene in Titan’s lakes, as high as 1 percent by volume. But this study, using the Visual and Infrared Mapping Spectrometer (VIMS) aboard Cassini, found very little acetylene on Titan’s surface.

Of course, one explanation for both discoveries is that something on Titan is consuming the hydrogen and acetylene.

Even though both findings are important, McKay feels the crux of any possible life on Titan hinges on verifying Strobel’s discovery about the lack of hydrogen.

“To me, the whole thing hovers on this determination of whether there is this flux of hydrogen is real,” McKay said via phone. “The acetylene has been missing and the ethane has been missing, but that certainly doesn’t generate a lot of excitement, because how much is supposed to be there depends on how much is being made. There are a lot of uncertainties.”

McKay stressed both results are still preliminary and the hydrogen loss in particular is the result of a computer calculation, and not a direct measurement. “It is the result of a computer simulation designed to fit measurements of the hydrogen concentration in the lower and upper atmosphere in a self-consistent way,” he said in a statement he put out over the weekend. “It is not presently clear from Strobel’s results how dependent his conclusion of a hydrogen flux into the surface is on the way the computer simulation is constructed or on how accurately it simulates the Titan chemistry.”

However, the findings are interesting for astrobiology, and would require the actual existence of methane-based life, a theory McKay himself proposed five years ago, which he described today as an “odd idea.”

In 2005, McKay and Heather Smith (McKay and Smith, 2005) suggested that methane-based life (rather than water-based) called methanogens on Titan could consume hydrogen, acetylene, and ethane. The key conclusion of that paper was “The results of the recent Huygens probe could indicate the presence of such life by anomalous depletions of acetylene and ethane as well as hydrogen at the surface.”

Even though the two new papers seem to show evidence for all three of these on Titan, McKay said this is a still a long way from “evidence of life”. However, it is extremely interesting.

But what does McKay really think?

“Unfortunately, if I was betting, the most likely explanation is that Darrel’s (Strobel) results are wrong and that further analysis will show there is another explanation for the data he is trying to fit, besides the strong flux of hydrogen into the surface. I would be very happy if we did confirm all that data, but we do have to take it in steps.”

McKay provided four possibilities for the recently reported findings, listed in order of their likely reality:

1. The determination that there is a strong flux of hydrogen into the surface is mistaken. “It will be interesting to see if other researchers, in trying to duplicate Strobel’s results, reach the same conclusion,” McKay said.

2. There is a physical process that is transporting H2 from the upper atmosphere into the lower atmosphere. One possibility is adsorption onto the solid organic atmospheric haze particles which eventually fall to the ground. However this would be a flux of H2, and not a net loss of H2.

3. If the loss of hydrogen at the surface is correct, the non-biological explanation requires that there be some sort of surface catalyst, presently unknown, that can mediate the hydrogenation reaction at 95 K, the temperature of the Titan surface. “That would be quite interesting and a startling find although not as startling as the presence of life,” McKay said.

4. The depletion of hydrogen, acetylene, and ethane, is due to a new type of liquid-methane based life form as predicted (Benner et al. 2004, McKay and Smith 2005, and Schulze-Makuch and Grinspoon 2005 (Astrobiology, vol. 5, no. 4., p. 560-567.).

McKay said if further analysis shows that a strong flux of hydrogen into the surface really is happening, “then my first two explanations are no longer options and we are then left with two really quite remarkable alternatives, either there is some mysterious metalysis going on, which at 95 k is really hard to imagine, and would have enormous implications for things like chemical engineering. And the second alternative is that there is life, which is even more amazing.”

“So to make process on this,” McKay continued, “we have to confirm Darrel’s result that there is hydrogen being fluxed onto the surface of Titan, that is really way unexpected, and unfortunately, it constitutes extraordinary claims that need extraordinary evidence. Darrel’s paper is just a first step in that.”

What does McKay think about the rash of media reports claiming life on Titan?

“Well, I think it reflects our human fascination and desire to find life out there,” he said. “We want it to be true. When we’re given a set of facts, if they are consistent with biology we jump to that explanation first. The most biologically interesting explanation is the first one we look to. We ought to give that a name — something like ‘Carl Sagan’s Razor’ as opposed to ‘Occam’s Razor,’ which would say that ‘The most exciting explanation is assumed to be true until it is proven false.'”

You can read all of McKay’s written response on the CICLOPS website, which Porco said will be “the first installment in a new feature on the CICLOPS website, called ‘Making Sense of the News’, where from time to time, scientists, both involved in Cassini and not, will be invited to comment on new developments that bear on the exploration of the solar system and the study of planetary systems, including our own.”

Posted on by Nancy Atkinson

New Discovery Supports Possibility of Microbial Life on Mars

Lost Hammer Spring on Axel Heiberg Island, Nunavut Territory, Canada. Credit: Dept. Natural Resource Sciences, McGill University, Montreal.

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The discovery of methane-eating bacteria in a very unique region of Canada’s extreme north supports the theory that similar organisms could be on Mars. Researchers have found methane-eating bacteria in a cold, methane filled spring located on Axel Heiberg Island in Canada, and say the spring is similar to possible past or present springs on Mars, and that therefore they too could support life.

The spring, called Lost Hammer supports microbial life. It is so salty that it doesn’t freeze despite the cold, and it has no consumable oxygen in it, said Dr. Lyle Whyte from McGill University in Montreal. There are, however, big bubbles of methane that come to the surface, which made the research team – which also included scientists from National Research Council of Canada, the University of Toronto and the SETI Institute –curious as to whether the gas was being produced geologically or biologically and whether anything could survive in this extreme hypersaline subzero environment.

“We were surprised that we did not find methanogenic bacteria that produce methane at Lost Hammer,” Whyte said, “but we did find other very unique anaerobic organisms – organisms that survive by essentially eating methane and probably breathing sulfate instead of oxygen.”

The discoveries of methane and frozen water on Mars, along with recently formed gullies are similar to what is occurring on Axel Heiberg Island. The methane on Mars is quite intriguing since the short-lived gas is obviously being replenished in some way.

But just the fact that methane is on Mars could mean the planet could support life.

“The point of the research is that it doesn’t matter where the methane is coming from,” Whyte explained. “If you have a situation where you have very cold salty water, it could potentially support a microbial community, even in that extreme harsh environment.”

The Lost Hammer spring region is very analogous to Mars. “There are places on Mars where the temperature reaches relatively warm -10 to 0 degrees and perhaps even above 0 degrees C,” Whyte said, “and on Axel Heiberg it gets down to -50, easy. The Lost Hammer spring is the most extreme subzero and salty environment we’ve found. This site also provides a model of how a methane seep could form in a frozen world like Mars, providing a potential mechanism for the recently discovered Martian methane plumes.”

Source: McGill University

Posted on by Steve Nerlich

Astronomy Without A Telescope – Life In Cosmic Rays

Lightning and Thunder
Lightning

We all know that astronomy is just plain awesome – and pretty much everything that’s interesting in the world links back to astronomy and space science in one way or another. Here I’m thinking gravity, wireless internet and of course ear thermometers. But wouldn’t it be great if we could ascribe the whole origin of life to astronomy as well? Well, apparently we can – and it’s all about cosmic rays.

Three key contenders for how it all started are:

1) Deep ocean vents, with heat, water and lots of chemistry churning away, enabled the random creation of a self-replicating crystalline compound – which, being self-replicating, rapidly came to dominate an environment of limited raw materials. From there, because it was imperfectly self-replicating, particular forms that were slightly more efficient at utilizing those limited resources came to dominate over other forms and yada, yada;

2) Something arrived on a comet or asteroid. This is the panspermia hypothesis, which just pushes the problem one step back, since life still had to start somewhere else. A bit like the whole God hypothesis really. Nonetheless, it’s a valid option; and

3) The Miller-Urey experiment demonstrated that if you zap a simple mix of water, methane, ammonia and hydrogen with an electric spark, roughly equivalent to a lightning bolt in the early Earth’s prebiotic atmosphere, you convert about 15% of the carbon present in that inorganic atmosphere into organic compounds, notably 22 amino acid types. From this base, it’s assumed that a self-replicating molecule came to be and from there… well, see point 1).

Additional support for the Miller-Urey option comes from the analysis of ‘old’ genes, being genes which are common to a wide diversity of different species and are hence likely to have been passed down from a common early ancestor. It’s found that these old genes preferentially code for amino acids that can be produced in the Miller-Urey experiment, being the only amino acids that would have been available to early Earth organisms. Only later did a much larger set of amino acids become available when subsequent generations of organisms began to learn how to synthesize them.

Nonetheless, Elykin and Wolfendale argue that the available spark energy generated in a average lightning storm would not have been sufficient to generate the reactions of the Miller-Urey experiment and that an extra factor is needed to somehow intensify the lightning in early Earth’s atmosphere. This is where cosmic rays come in.

An electron air shower produced by a high energy cosmic ray particle.

While many cosmic rays are generated by solar activity and most don’t penetrate far into the atmosphere, high energy cosmic ray particles, which generally originate from outside the solar system, can create electron air showers. These arise from a cosmic ray particle colliding with an atmospheric particle producing a cascade of charged pions, which decay into muons and then electrons – resulting in a dense collection of electrons showering down to two kilometers or less above the Earth’s surface.

Such a dense electron air shower could initiate, enhance and sustain a high energy lightning storm and the researchers propose that, perhaps when the early solar system was drifting past some primeval supernova event over four billion years ago, this was what started it all.

Awesome.

Posted on by Nancy Atkinson

Are We Contaminating Mars?

A new image from the HiRISE camera on MRO showing mounds of south polar layered deposits. Credit: NASA/JPL/University of Arizona

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With Mars seemingly the destination of choice in NASA’s future, researchers are taking a look at what kinds of things we want to bring with us when we go to Mars. But also, just as important is what we don’t want to take with us. A new study by the University of Central Florida reveals that bacteria common to spacecraft may be able to survive the harsh environment of Mars long enough to inadvertently contaminate the Red Planet with terrestrial life. So, if we do find life on Mars, the question might be: is it them, or is it us?

The research team replicated Mars-like conditions, such as a very dry environment, low barometric pressure, cold temperatures and intense UV radiation. They exposed one of our favorite bacteria, E. coli (Escherichia coli) – which is a potential spacecraft contaminant– to these conditions for a week, and found it likely would survive but not grow on the surface of Mars if it were shielded from UV irradiation, such as in nooks and crannies in a spacecraft, or even if it was covered by thin layers of dust.

“If long-term microbial survival is possible on Mars, then past and future explorations of Mars may provide the microbial inoculum (biological materials) for seeding Mars with terrestrial life,” said the researchers. “Thus, a diversity of microbial species should be studied to characterize their potential for long term survival on Mars.”

Even though NASA and other space agencies do sterilize spacecraft in an effort to reduce the chance of contamination to other bodies in our solar system, recent studies have shown that microbial species are likely still hitching a ride. And in what might be a more-harm-than-good scenario, the sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, including acinetobacter, bacillus, escherichia, staphylococcus and streptococcus. So we’re likely sending the worst of the worst kinds of bacteria, at least by human standards.

This research was published in the April 2010 issue of the journal Applied and Environmental Microbiology.

Source: American Society for Microbiology

Posted on by Nancy Atkinson

Life on Titan Could Be Smelly and Explosive

Artist concept of Methane-Ethane lakes on Titan (Credit: Copyright 2008 Karl Kofoed). Click for larger version.

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Could there be life on Titan? If so, one astrobiologist says humans probably couldn’t be in the same room with a Titanian and live to tell about it. “Hollywood would have problems with these aliens” said Dr. William Bains. “Beam one onto the Starship Enterprise and it would boil and then burst into flames, and the fumes would kill everyone in range. Even a tiny whiff of its breath would smell unbelievably horrible. But I think it is all the more interesting for that reason. Wouldn’t it be sad if the most alien things we found in the galaxy were just like us, but blue and with tails?”

While giving an obvious nod to the recent movie “Avatar,” Bains’ research provides insight to the difficulties we might encounter – beyond cultural – if we ever meet up with alien life. There could be unintended harmful consequences for one species, or both.

Bains is working to find out just how extreme the chemistry of life can be. Life on Titan, Saturn’s largest moon, represents one of the more bizarre scenarios being studied. While images sent back by the Cassini/Huygens mission might make Titan look Earth-like and maybe even inviting, it has a thick atmosphere of frozen, orange smog. At ten times our distance from the Sun, it is a frigid place, with a surface temperature of -180 degrees Celsius. Water is permanently frozen into ice and the only liquid available is liquid methane and ethane.

So instead of water based-life (like us), life on Titan would likely be based on methane.

“Life needs a liquid; even the driest desert plant on Earth needs water for its metabolism to work. So, if life were to exist on Titan, it must have blood based on liquid methane, not water. That means its whole chemistry is radically different. The molecules must be made of a wider variety of elements than we use, but put together in smaller molecules. It would also be much more chemically reactive,” said Bains.

Additionally, Bains said a metabolism running in liquid methane would have to be built of smaller molecules than terrestrial biochemistry.

“Terrestrial life uses about 700 molecules, but to find the right 700 there is reason to suppose that you need to be able to make 10 million or more,” Bains said. “The issue is not how many molecules you can make, but whether you can make the collection you need to assemble a metabolism.”

Bains said doing such assembling is like trying to find bits of wood in a lumber-yard to make a table.

“In theory you only need 5,” he said. “But you may have a lumber-yard full of offcuts and still not find exactly the right five that fit together. So you need the potential to make many more molecules than you actually need. Thus the 6-atom chemicals on Titan would have to include much more diverse bond types and probably more diverse elements, including sulphur and phosphorus in much more diverse and (to us) unstable forms, and other elements such as silicon.”

Energy is another factor that would affect the type of life that could evolve on Titan. With Sunlight a tenth of a percent as intense on Titan’s surface as on the surface of Earth, energy is likely to be in short supply.

“Rapid movement or growth needs a lot of energy, so slow-growing, lichen-like organisms are possible in theory, but velociraptors are pretty much ruled out,” said Bains.

Whatever life may be on Titan, at least we know there won’t be a Jurassic Park.

Bains, whose research is carried out through Rufus Scientific in Cambridge, UK, and MIT in the USA, is presenting his research at the National Astronomy Meeting in Glasgow, Scotland on April 13, 2010.

Source: RAS NAM