Posted on by Tammy Plotner

Europa’s Acidic Oceans May Prohibit Life

Europa's bizarre surface features suggest an actively churning ice shell above a salty liquid water ocean. That liquid could carry amino acids and signs of life to the surface. Credit: JPL
Europa's bizarre surface features suggest an actively churning ice shell above a salty liquid water ocean. That liquid could carry amino acids and signs of life to the surface. Credit: JPL

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The more we explore our solar system, the more we find things in common. Jupiter’s frigid moon – Europa – is about the size of our satellite and – like Earth – home to some very hostile environments. Underneath what is surmised to be an icy crust a few miles deep, Europa may possess an acidic ocean that could extend down as much as 100 miles (160 km) below the surface. We know from exploring our home planet that life happens under some very extreme conditions here… But what about Europa? What are the chances that life could exist there, too?

Check out liquid water on Earth and you’ll find some form of life. As a given, scientists hypothesize other worlds which contain water should also support life. According to recent studies, Europa’s ocean might even be saturated with oxygen – further supporting these theories. However, there’s a catch. Like Earth, surface chemicals are continually drawn downward. According to researcher Matthew Pasek, an astrobiologist at the University of South Florida, this could constitute a highly acidic ocean which “is probably not friendly to life — it ends up messing with things like membrane development, and it could be hard building the large-scale organic polymers.”

According to Charles Choi of Astrobiology Magazine, “The compounds in question are oxidants, which are capable of receiving electrons from other compounds. These are usually rare in the solar system because of the abundance of chemicals known as reductants such as hydrogen and carbon, which react quickly with oxidants to form oxides such as water and carbon dioxide. Europa happens to be rich in strong oxidants such as oxygen and hydrogen peroxide which are created by the irradiation of its icy crust by high-energy particles from Jupiter.”

Although it’s speculation, if Europa produces oxidants, they may also be drawn toward its core from ocean motion. However, it might be infused with sulfides and other compounds creating sulfuric and other acids before supporting life. According to the researchers, if this has happened for just half of Europa’s lifetime, the result would be corrosive, with a pH of about 2.6, “about the same as your average soft drink,” Pasek said. While this wouldn’t prohibit life from forming, it wouldn’t make it easy. Emerging life forms would have to be quick to consume oxidants and build an acid tolerance – a process which could take as much as 50 million years.

Are there similar acid-lovin’ lifeforms on Earth? You bet. They exist in acid mine drainage found in Spain’s Rio Tinto river and they feed on iron and sulfide for their metabolic energy. “The microbes there have figured out ways of fighting their acidic environment,” Pasek said. “If life did that on Europa, Ganymede, and maybe even Mars, that might have been quite advantageous.” It is also possible that sediments at the bottom of Europa’s ocean may neutralize the acids, even though Pasek speculates this isn’t likely. One thing we do know about an acidic ocean is that it dissolves calcium-based materials such as bones and shells.

It’s a lesson repeated on Earth…

Right now our oceans are absorbing excess carbon dioxide from the air which – when combined with seawater – forms carbonic acid. While it is mostly neutralized by fossil carbonate shells at the ocean’s bed, if it’s absorbed too quickly it can have some major ramifications on sea life such as coral reefs, plankton and mollusks. According to a recent study, this acidification is happening faster (thanks to human carbon emissions) than it has during four major extinction events on Earth in the last 300 million years.

“What we’re doing today really stands out,” said lead author Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “We know that life during past ocean acidification events was not wiped out—new species evolved to replace those that died off. But if industrial carbon emissions continue at the current pace, we may lose organisms we care about—coral reefs, oysters, salmon.”

According to this new research, our carbon dioxide levels have escalated by 30% in the last century. This means we’ve jumped to to 393 parts per million, and ocean pH has fallen by 0.1 unit, to 8.1–an acidification rate at least 10 times faster than 56 million years ago, says Hönisch. If this continues, the Intergovernmental Panel on Climate Change predicts the pH may drop as much as another 0.3 units… a drop that will constitute major biologic changes. While you might scoff at the extinction of a few forms of plankton or the annihilation of a small coral or shellfish, there is a ripple effect that cannot be denied.

“It’s not a problem that can be quickly reversed,” said Christopher Langdon, a biological oceanographer at the University of Miami who co-authored the study on Papua New Guinea reefs. “Once a species goes extinct it’s gone forever. We’re playing a very dangerous game.”

It may take decades before ocean acidification’s effect on marine life shows itself. Until then, the past is a good way to foresee the future, says Richard Feely, an oceanographer at the National Oceanic and Atmospheric Administration who was not involved in the study. “These studies give you a sense of the timing involved in past ocean acidification events—they did not happen quickly,” he said. “The decisions we make over the next few decades could have significant implications on a geologic timescale.”

For now, we’ll look to Europa and wonder at what may exist below its frozen waves. Is there an acid-loving form of life just waiting to bubble to the surface for us to find? Right now researchers are developing a drill which could assist in looking for extreme forms of life. The “penetrator” could eventually be part of a Europa exploration mission which could begin as early as 2020.

“Penetrators are the most feasible, cheapest and safest option for a landing on Europa today, and the knowledge to build those is there,” said Peter Weiss, a post-doc now at the National Center for Scientific Research (CNRS) in France. “Otherwise, we won’t have any confirmation on astrobiology on Europa — or maybe even in the solar system — during our lifetime.”

Original Story Source: Astrobiology Magazine. For Further Reading: Physorg.com.

Posted on by Nancy Atkinson

Life in the Universe, Reflected by the Moon

This view shows the thin crescent Moon setting over ESO’s Paranal Observatory in Chile. Credit: ESO/B. Tafreshi/TWAN

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Earthshine – a poetic, fanciful word for the soft, faint glow on the Moon when the light from the Sun is reflected from the Earth’s surface, onto the dark part of the Moon. And as unlikely as it might seem, astronomers have used Earthshine to verify there’s life in the Universe: Us. While we already know about life on our own world, this technique validates that faint light from distant worlds could also be used to find potential alien life.

“We used a trick called earthshine observation to look at the Earth as if it were an exoplanet,” said Michael Sterzik from the European Southern Observatory. “The Sun shines on the Earth and this light is reflected back to the surface of the Moon. The lunar surface acts as a giant mirror and reflects the Earth’s light back to us — and this is what we have observed with the VLT (Very Large Telescope).”

Sterzik and his team said the fingerprints of life, or biosignatures, are hard to find with conventional methods, but they have now pioneered a new approach that is more sensitive. The astronomers used Earth as a benchmark for the future search for life on planets beyond our Solar System. They can analyze the faint planetshine light to look for indicators, such as certain combinations of gases in the atmosphere – as they found looking at earthshine – to find telltale signs of organic life.

Looking at earthshine, they found strong bio-signatures such as molecular oxygen and methane, as well as the presence of a ‘red edge’ caused by surface vegetation.

By observing earthshine astronomers can study the properties of light reflected from Earth as if it were an exoplanet and search for signs of life. The reflected light is also strongly polarised and studying the polarisation as well as the intensity at different colours allows for much more sensitive tests for the presence of life. Credit: ESO/L. Calçada

Instead of just looking at the planet’s reflected light, astronomers can also use spectropolarimetry, which looks at the polarization of the light. Using this approach, the biosignatures in the reflected light from Earth show up very strongly.

“The light from a distant exoplanet is overwhelmed by the glare of the host star, so it’s very difficult to analyze — a bit like trying to study a grain of dust beside a powerful light bulb,” said co-author Stefano Bagnulo from Armagh Observatory in Northern Ireland. “But the light reflected by a planet is polarised, while the light from the host star is not. So polarimetric techniques help us to pick out the faint reflected light of an exoplanet from the dazzling starlight.”

By looking at earthshine, the team was able to deduce that the Earth’s atmosphere is partly cloudy, that part of its surface is covered by oceans and — crucially — that there is vegetation present. They could even detect changes in the cloud cover and amount of vegetation at different times as different parts of the Earth reflected light towards the Moon.

“These observations allow us to determine the fractional contribution of clouds and ocean surface, and are sensitive to Spectropolarimetry unveils strong biosignatures, visible areas of vegetation as small as 10%,” the team wrote in their paper.

“Finding life outside the Solar System depends on two things: whether this life exists in the first place, and having the technical capability to detect it,” said co-author Enric Palle from Instituto de Astrofisica de Canarias, Tenerife, Spain. “This work is an important step towards reaching that capability.”

“Spectropolarimetry may ultimately tell us if simple plant life — based on photosynthetic processes — has emerged elsewhere in the Universe,” said Sterzik. “But we are certainly not looking for little green men or evidence of intelligent life.”

The astronomers said that future telescopes such as the E-ELT (the European Extremely Large Telescope), could provide more detail about the type of life beyond planets that may exists on another world.

Read the team’s paper, (pdf) which was published in Nature.

Source: ESO

Posted on by Jason Major

SOLID Clues for Finding Life on Mars

Microbes have been found flourishing beneath the surface of the Atacama Desert. (Parro et al./CAB/SINC)

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Researchers from the Center of Astrobiology (CAB) in Spain and the Catholic University of the North in Chile have found an “oasis” of microorganisms living two meters beneath the arid soil of the Atacama, proving that even on the driest place on Earth, life finds a way.

Chile’s Atacama Desert receives on average less than .01 cm (.004 inches) of rain per year. In some locations rain has not fallen for over 400 years. But even in this harsh environment there is moisture… just enough, at least, for rock salts and other compounds that can absorb any traces of water to support microbial life beneath the surface.

Using a device called SOLID (Signs Of LIfe Detection) developed by CAB, the researchers were able to identify the presence of microorganisms living on thin films of water within the salty subsurface soil.

Even the substrate itself is able to absorb moisture from the air, concentrating it into films only a few microns thick around the salt crystals. This gives the microorganisms everything they need to survive and flourish — two to three meters underground.

SOLID's array of life-detector modules. (CAB)

At that depth, there is no sunlight and no oxygen, but there is life.

And even when researchers dug to a depth of five meters (a little over 16 feet) and took samples back to a lab, they were able to not only locate microorganisms but also revive them with the addition of a little water.

Of course, the implications for finding life — or at least the remains of its past existence — on Mars is evident. Mars has been shown to have saline deposits in many regions, and the salt is what helps water remain liquid, longer.

“The high concentration of salt has a double effect: it absorbs water between the crystals and lowers the freezing point, so that they can have thin films of water (in brine) at temperatures several degrees below zero, up to minus 20 C,” said Victor Parro, researcher from the Center of Astrobiology (INTA-CSIC, Spain) and coordinator of the study. This is within the temperature range of many regions of Mars, and also anything located several meters below the surface would be well protected from UV radiation from the Sun.

“If there are similar microbes on Mars or remains in similar conditions to the ones we have found in Atacama, we could detect them with instruments like SOLID,” Parro said.

The development of a new version of the SOLID instrument is currently underway for ESA’s ExoMars program.

Read more here on the Science Codex article.

What might be found just a few feet under the surface of Mars? (NASA/JPL-Caltech)
Posted on by Tammy Plotner

Ancient Antarctic Ice Sampled In Lake Vostok Drill

Panoramic photo of Vostok Station showing the layout of the camp. Credit: Todd Sowers LDEO, Columbia University, Palisades, New York (Image from physorg.com)

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Sealed off for millions of years beneath an almost impenetrable layer of ice, Lake Vostok has kept a vast archive of ancient history waiting for just the right moment to reveal itself. Here is a unique closed ecosystem captured in time below four kilometers of ice. Saved from environmental contamination, its water has been isolated from Earth’s atmosphere, and the outside world, long before man existed. Only one burning question remains… Could this pristine pocket of Lake Vostok show signs of early life?

“According to our research, the quantity of oxygen there exceeds that on other parts of our planet by 10 to 20 times. Any life forms that we find are likely to be unique on Earth,” says Sergey Bulat, the Chief Scientist of Russia’s Antarctic Expedition to Russian Reporter magazine.

So why be so excited over finding a few organisms? The reason is clear as the hidden waters. If a life form could exist here, it could also exist on a similar world…. Jupiter’s satellite, Europa.

“The discovery of microorganisms in Lake Vostok may mean that, perhaps, the first meeting with extra-terrestrial life could happen on Europa,” said Dr Vladimir Kotlyakov, Director of the Geography Institute at the Russian Academy of Sciences to Vzglyad newspaper.

Image from earth.columbia.edu
However, drilling through over 3,700 meters of pure ice hasn’t been an easy process – especially when you’re working in temperatures as low as minus 80 centigrade. The chill thrill drill began in 1970, but it was over 25 years later before Russian specialists discovered the hidden lake beneath the ice sheet. Along with British support, they then began sonar and satellite imagining to reveal one of the world’s largest undisclosed fresh water reservoirs. Now, speculation began in earnest. What might these waters contain? Could it be tiny microbes? Or perhaps even a dangerous organism… There was only one way to find out. Drill and sample.

“Everything but the samples themselves will be carefully decontaminated using radiation. There is no need to worry,” Valeriy Lukin, Head of the Antarctic Expedition told Russian Reporter Magazine. According to researchers at the Russian Arctic and Antarctic Research Institute, they surmise the findings as “the only giant super-clean water system on the planet.” and pristine water will be “twice cleaner than double-distilled water.”

Over the last few decades, there had been a lot of discord over anti-freeze drilling methods – each with its pros and cons. From kerosene to Freon – even hot water – the end result needed to be the same. No chance of contamination… either to the samples or the native environment. As it ended up, the Russian method of using the former turned out to be fine when 40 liters of frozen, pure water came to light on February 4. Just a day later, 1,500 liters of kerosene and Freon poured into special containers with no problems and the sample proved to be immaculate. The clear waters are now safely tucked away in sterile containers and are heading back home.

“I can say that everyone at Bellingshausen on the Antarctic Peninsula could probably tell you down to the meter what the daily progress of the drilling was at the Vostok Station in the center of the continent.” says reporter, Sean Thomas. ” After all, the work at Lake Vostok was a Russian project, at a Russian base with Russian scientists, so there is a lot of pride in the work that is being done there.”

Original Story Source: RT News.

Posted on by Amy Shira Teitel

Looks Like We’re Still Looking for Earthly Life Forms on Other Planets

GFAJ-1, the bacterium found in California's Lake Mono. Image credit: Science/AAAS

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In late 2010, NASA set the Internet buzzing when it called a press conference to discuss an astrobiological finding that would impact the search for extraterrestrial life. Many speculated that some primitive life had been found on Mars or one of Saturn’s moons. But the evidence was found on Earth; a strain of bacteria in California’s Lake Mono that had arsenic in its genetic structure. The discovery implied that life could thrive without the elements NASA typically looks for, mainly carbon and phosphorous. But now, a new study challenges the existence of arsenic-based life forms. 

The 2010 paper announcing arsenic based life, “Arsenic-eating microbe may redefine chemistry of life,” was written by a team of scientists led by Felisa Wolfe-Simon. The paper appeared in Science and refuted the long-held assumption that all living things need phosphorus to function, as well as other elements including carbon, hydrogen, and oxygen.

Lake Mono, as seen from Space. Image credit: NASA

The phosphate ion plays several essential roles in cells: it maintains the structure of DNA and RNA, it combines with lipids to make cell membranes, and it transports energy within the cell through the molecule adenosine triphosphate (ATP). Finding a bacteria that uses normally poisonous arsenic in the place of phosphate shook up the guidelines that have structured NASA’s search for life on other worlds.

But microbiologist Rosie Redfield didn’t agree with Wolfe-Simon’s article and published her concerns as technical comments in subsequent issues of Science. Then, she put Wolfe-Simon’s results to the test. She led a team of scientists at the University of British Columbia in Vancouver and tracked her progress online in the name of open science.

Redfield followed Wolfe-Simon’s procedure. She grew GFAJ-1 bacteria, the same strain found in Lake Mono, in a solution of arsenic with a very small amount of phosphorus. She then purified DNA from the cells and sent the material to Princeton University in New Jersey. There, graduate student Marshall Louis Reaves separated the DNA into fractions of varying densities using caesium chloride centrifugation. Caesium chloride, a salt, creates a density gradient when mixed with water and put in a centrifuge. Any DNA in the mixture will settle throughout the gradient depending on its structure. Reaves studied the resulting DNA gradient using a mass spectrometer to identify the different elements at each density. He found no trace of arsenic in the DNA.

Redfield’s results aren’t by themselves conclusive; one experiment isn’t enough to definitively disprove Wolfe-Simon’s arsenic-life paper. Some biochemists are eager to continue the research and want to figure out the lowest possible level of arsenic that Redfield’s method could detect as a way of determining exactly where arsenic from the GFAJ-1 DNA ends up on a caesium chloride gradient.

Dr. Redfield. Image credit: M. Dee/Nature

Wolfe-Simon is also not taking Redfield’s results as conclusive; she is still looking for arsenic in the bacterium. “We are looking for arsenate in the metabolites, as well as the assembled RNA and DNA, and expect others may be doing the same. With all this added effort from the community, we shall certainly know much more by next year.”

Redfield, however, isn’t planning any follow-up experiments to support her initial findings. “What we can say is that there is no arsenic in the DNA at all,” she said. “We’ve done our part. This is a clean demonstration, and I see no point in spending any more time on this.”

It’s unlikely that scientists will conclusively prove or disprove the existence arsenic-based life anytime soon. For the time being, NASA will likely confine its search for extraterrestrial life to phosphorus-dependent forms we know exist.

Source: nature.com

Posted on by Ken Kremer

Crucial Rocket Firing Puts Curiosity on Course for Martian Crater Touchdown

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NASA’s car-sized Curiosity Mars Science Lab (MSL) rover is now on course to touch down inside a crater on Mars in August following the completion of the biggest and most crucial firing of her 8.5 month interplanetary journey from Earth to the Red Planet.

Engineers successfully commanded an array of thrusters on MSL’s solar powered cruise stage to carry out a 3 hour long series of more than 200 bursts last night (Jan. 11) that changed the spacecraft’s trajectory by about 25,000 miles (40,000 kilometers) – an absolute necessity that actually put the $2.5 Billion probe on a path to Mars to “Search for Signatures of Life !”

“We’ve completed a big step toward our encounter with Mars,” said Brian Portock of NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif., deputy mission manager for the cruise phase of the mission. “The telemetry from the spacecraft and the Doppler data show that the maneuver was completed as planned.”

Mars Science Lab and cruise stage separate from Centaur upper stage just minutes after Nov. 26, 2011 launch. Thrusters on cruise stage performed course correction on Jan. 11, 2012. Up to 6 firings total will put the NASA robot on precision course to Mars.
Credit: NASA TV

This was the first of six possible TCM’s or trajectory correction maneuvers that may be required to fine-tune the voyage to Mars.

Until now, Curiosity was actually on a path to intentionally miss Mars. Since the Nov. 26, 2011 blastoff from Florida, the spacecraft’s trajectory was tracking a course diverted slightly away from the planet in order to prevent the upper stage – trailing behind – from crashing into the Red Planet.

The upper stage was not decontaminated to prevent it from infecting Mars with Earthly microbes. So, it will now sail harmlessly past the planet as Curiosity dives into the Martian atmosphere on August 6, 2012.

The thruster maneuver also served a second purpose, which was to advance the time of the Mars encounter by about 14 hours. The TCM burn increased the velocity by about 12.3 MPH (5.5 meters per second) as the vehicle was spinning at 2 rpm.

“The timing of the encounter is important for arriving at Mars just when the planet’s rotation puts Gale Crater in the right place,” said JPL’s Tomas Martin-Mur, chief navigator for the mission.


Video caption: Rob Manning, Curiosity Mars Science Lab Chief Engineer at NASA JPL describes the Jan. 11, 2012 thruster firing that put the robot on a precise trajectory to Gale Crater on Mars. Credit: NASA/JPL

As of today, Jan. 12, the spacecraft has traveled 81 million miles (131 million kilometers) of its 352-million-mile (567-million-kilometer) flight to Mars. It is moving at about 10,300 mph (16,600 kilometers per hour) relative to Earth, and at about 68,700 mph (110,500 kilometers per hour) relative to the Sun.

The next trajectory correction maneuver is tentatively scheduled for March 26, 2012.

Curiosity rover launches to Mars atop Atlas V rocket on Nov. 26, 2011 from Cape Canaveral, Florida. Credit: Ken Kremer

The goal of the 1 ton Curiosity rover is to investigate whether the layered terrain inside Gale Crater ever offered environmental conditions favorable for supporting Martian microbial life in the past or present and if it preserved clues about whether life ever existed.

Curiosity will search for the ingredients of life, most notably organic molecules – the carbon based molecules which are the building blocks of life as we know it. The robot is packed to the gills with 10 state of the art science instruments including a 7 foot long robotic arm, scoop, drill and laser rock zapper.

Curiosity’s Roadmap through the Solar System-From Earth to Mars
Schematic shows 8.5 month interplanetary trajectory of Curiosity. Credit: NASA/JPL-Caltech

Curiosity Countdown – 205 days to go until Curiosity lands at Gale Crater on Mars !

January 2012 marks the 8th anniversary of the landings of NASA’s Spirit and Opportunity Mars rovers back in January 2004.

Opportunity continues to operate to this day. Read my salute to Spirit here

Read continuing features about Curiosity and Mars rovers by Ken Kremer starting here:
8 Years of Spirit on Mars – Pushing as Hard as We Can and Beyond !
2011: Top Stories from the Best Year Ever for NASA Planetary Science!
Opportunity Discovers Most Powerful Evidence Yet for Martian Liquid Water
Flawlessly On Course Curiosity Cruising to Mars – No Burn Needed Now
NASA Planetary Science Trio Honored as ‘Best of What’s New’ in 2011- Curiosity/Dawn/MESSENGER
Curiosity Mars Rover Launch Gallery – Photos and Videos
Curiosity Majestically Blasts off on ‘Mars Trek’ to ascertain ‘Are We Alone?
Mars Trek – Curiosity Poised to Search for Signs of Life

Posted on by Tammy Plotner

Planetary Habitability Index Proposes A Less “Earth-Centric” View In Search Of Life

Artist concept of an exoplanet. Credit: David A. Hardy.

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It’s a given. It won’t be long until human technology will expand our repertoire of cataloged exoplanets to astronomical levels. Of these, a huge number will be considered within the “habitable zone”. However, isn’t it a bit egotistical of mankind to assume that life should be “as we know it”? Now astrobiologists/scientists like Dirk Schulze-Makuch with the Washington State University School of Earth and Environmental Sciences and Abel Mendez from the University of Puerto Rico at Aricebo are suggesting we take a less limited point of view.

“In the next few years, the number of catalogued exoplanets will be counted in the thousands. This will vastly expand the number of potentially habitable worlds and lead to a systematic assessment of their astrobiological potential. Here, we suggest a two-tiered classification scheme of exoplanet habitability.” says Schulze-Makuch (et al). “The first tier consists of an Earth Similarity Index (ESI), which allows worlds to be screened with regard to their similarity to Earth, the only known inhabited planet at this time.”

Right now, an international science team representing NASA, SETI,the German Aerospace Center, and four universities are ready to propose two major questions dealing with our quest for life – both as we assume and and alternate. According to the WSU news release:

“The first question is whether Earth-like conditions can be found on other worlds, since we know empirically that those conditions could harbor life,” Schulze-Makuch said. “The second question is whether conditions exist on exoplanets that suggest the possibility of other forms of life, whether known to us or not.”

Within the next couple of weeks, Schulze-Makuch and his nine co-authors will publish a paper in the Astrobiology journal outlining their future plans for exoplanet classification. The double approach will consist of an Earth Similarity Index (ESI), which will place these newly found worlds within our known parameters – and a Planetary Habitability Index (PHI), that will account for more extreme conditions which could support surrogate subsistence.

“The ESI is based on data available or potentially available for most exoplanets such as mass, radius, and temperature.” explains the team. “For the second tier of the classification scheme we propose a Planetary Habitability Index (PHI) based on the presence of a stable substrate, available energy, appropriate chemistry, and the potential for holding a liquid solvent. The PHI has been designed to minimize the biased search for life as we know it and to take into account life that might exist under more exotic conditions.”

Assuming that life could only exist on Earth-like planets is simply narrow-minded thinking, and the team’s proposal and modeling efforts will allow them to judiciously filter new discoveries with speed and high level of probability. It will allow science to take a broader look at what’s out there – without being confined to assumptions.

“Habitability in a wider sense is not necessarily restricted to water as a solvent or to a planet circling a star,” the paper’s authors write. “For example, the hydrocarbon lakes on Titan could host a different form of life. Analog studies in hydrocarbon environments on Earth, in fact, clearly indicate that these environments are habitable in principle. Orphan planets wandering free of any central star could likewise conceivably feature conditions suitable for some form of life.”

Of course, the team admits an alien diversity is surely a questionable endeavor – but why risk the chance of discovery simply on the basis that it might not happen? Why put a choke-hold on creative thinking?

“Our proposed PHI is informed by chemical and physical parameters that are conducive to life in general,” they write. “It relies on factors that, in principle, could be detected at the distance of exoplanets from Earth, given currently planned future (space) instrumentation.”

Original News Source: WSU News. For Further Reading: A Two-Tiered Approach to Assessing the Habitability of Exoplanets.

Posted on by Amy Shira Teitel

Could Electrical Sprites Hold the Key to Extraterrestrial Life?

Full color image of a red lightning sprite.

 

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In 1989, meteorologists discovered sprites. Not the spirits, elves, or pixies that pepper Shakespearean comedies but their equally elusive electrical namesakes. Lightning sprites are large scale electrical discharges inside the clouds above storms that make the upper atmosphere glow, sort of like a fluorescent lightbulb.

Meteorologists have already determined that sprites likely aren’t unique to Earth. In fact, this elusive form of lightning might be common throughout the solar system. Now, researchers at Tel Aviv University are asking whether the presence of sprites on other planets could indicate the presence of organic material in their atmospheres.  

The layers of our atmosphere. Image credit: National Weather Service, JetStream Online School for Weather.

Though not an uncommon phenomena, sprites are incredibly hard to find and observe. They can only be captured with highly sensitive high speed cameras. Sprites occur in the Earth’s Mesosphere, layer between the stratosphere and the thermosphere – about 50 km (31 miles) to 90 km (56 miles) high. At this altitude, the gases that make up our atmosphere are much thinner and unable to hold heat from the Sun making the average temperature a chilly 5°F (-15°C) to as low as -184°F (-120°C).

But gases at this altitude are still thick enough to slow meteors – this is where they burn up and create what we see as meteor showers. Gases in the mesosphere are also thick enough to light up with sprites, providing a window into the composition of our atmosphere. Sprites, which glow reddish-orange, indicate the kinds of molecules present in this layer of the atmosphere.

Lightning isn’t a rare occurrence in our solar system, which leads researchers to suspect sprites might be found on Jupiter, Saturn, and Venus – all planets with the right environment for strong electrical storms. Just like on Earth, sprites found on these planets could open a window in their atmospheric composition, conductivity, and possibly point to the presence of exotic compounds.

Jupiter and Saturn present the most exciting environments. Both gas giants experience lightening storms with flashes more than 1,000 as powerful as those found on Earth. It’s on these planets that Ph.D. student Daria Dubrovin, with her supervisors Prof. Colin Price of Tel Aviv University’s Department of Geophysics and Planetary Sciences and Prof. Yoav Yair at the Open University of Israel, is focussing on.

Dubrovin has re-created these planetary atmospheres in a lab to study the presence of sprites in space. Or, as she describes her work, “We make sprites in a bottle.” She hopes this will provide a new understanding of electrical and chemical processes on other planets.

A sprite as it might appear in Saturn's atmosphere, created in a TAU lab. Image credit: American Friends, Tel Aviv University

What’s more, understanding lightning on other worlds could help researchers understand the possibility of life on other worlds. As Dubrovin points out, lightning is commonly accepted as the generator of organic molecules that turned early Earth’s ocean into the life-filled primordial soup. Increased study of lightning on other planets could give another clue into the presence of extraterrestrial life. Their research could easily be applied to exoplanets, not just bodies in our solar system.

A lightning storm on Saturn has Dubrovin pretty excited. It’s currently producing over 100 electrical flashes per second, a rare occurrence even within the planet’s volatile cloud layers. If researchers could successfully gather images of higher altitude sprites from the Cassini spacecraft (currently in orbit around Saturn), it would not only yield information on the storm below but also add to the general knowledge base of sprites and lightning on other planets.

Video of Sprites from the University of Alaska

Source: Tel Aviv University

Posted on by Tammy Plotner

Alien Artifacts May Be Here… Just Hard To Find!

This image highlights the special cargo onboard NASA's Voyager spacecraft: the Golden Record. Each of the two Voyager spacecraft launched in 1977 carry a 12-inch gold-plated phonograph record with images and sounds from Earth. An artist's rendering of the Voyager spacecraft is shown at bottom right, with a yellow circle denoting the location of the Golden Record. The cover of the Golden Record, shown on upper right, carries directions explaining how to play the record, a diagram showing the location of our sun and the two lowest states of the hydrogen atom as a fundamental clock reference. The larger image to the left is a magnified picture of the record inside. Credit: NASA

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Greeting cards in space… We’ve certainly sent our share of them, haven’t we? So if humankind is foresighted enough to leave messages of our whereabouts – and our personalities – in space, then why haven’t other alien civilizations done the same? That’s a question a pair of postdoctoral researchers at Penn State are asking. By using mathematical equations, they’re showing us we simply haven’t looked in enough places… and would we recognize an alien artifact even if it were staring us in the face?

“The vastness of space, combined with our limited searches to date, implies that any remote unpiloted exploratory probes of extraterrestrial origin would likely remain unnoticed,” report Jacob Haqq-Misra, Rock Ethics Institute, and Ravi Kumar Kopparapu, Earth and Environmental Systems Institute, in a paper accepted by Acta Astronautica and posted online on ArXiv.

So far, we simply haven’t found any evidence of alien artifacts in our solar system – or anywhere else for that matter. According to the Penn State article, the Fermi paradox, originally formulated by Enrico Fermi, asks, if intelligent life is common, why have no technological civilizations been observed. Well, shucks… Maybe they’re shy – and maybe they’ve self-annihilated. There are hundreds of reasons “why” we haven’t found anything, but the most pertinent answer is we simply aren’t looking for the right thing in the right place at the right time. For example, have a look at just a few of the things we humans have sent into vastness of space to act as our ambassadors…

Duke Family Portrait: Apollo 16 Journal - Courtesy of Markus Mehring - Credit: NASA AS16-117-18841
Pioneer 10 and 11's famed Plaque features a design engraved into a gold-anodized aluminum plate, 152 by 229 millimeters (6 by 9 inches), attached to the spacecrafts' antenna support struts to help shield it from erosion by interstellar dust. Image Credit: NASA
Three LEGO figurines representing the Roman god Jupiter, his wife Juno and Galileo Galilei are shown here aboard the Juno spacecraft. Image credit: NASA/JPL-Caltech/KSC NASA's Jupiter-bound Juno spacecraft will carry the 1.5-inch likeness of Galileo Galilei, the Roman god Jupiter and his wife Juno to Jupiter when the spacecraft launches this Friday, Aug. 5. The inclusion of the three mini-statues, or figurines, is part of a joint outreach and educational program developed as part of the partnership between NASA and the LEGO Group to inspire children to explore science, technology, engineering and mathematics. Credit: NASA

And this is only just the tip of the human iceberg. How many of us have sent our name on missions to Mars, Pluto and more? There are footprints, plaques, flags, golf balls and an endless parade of human artifacts scattered far and wide. We might think they’re in plain sight, but would an alien culture see that? Would we comprehend what an alien culture might consider to be a greeting or sign or their presence? As far as we know, there could be unpiloted probes from alien civilizations out there right now, checking us out… But unless it were something the size of a proverbial school bus dropping itself on a house in Essex, our own arrogance would probably keep us from noticing it. And then again… it just might be hidden.

“Extraterrestrial artifacts may exist in the Solar System without our knowledge simply because we have not yet searched sufficiently,” said Haqq-Misra and Kopparapu. “Few if any of the attempts would be capable of detecting a 1 to 10 meter (3 to 33 foot) probe.”

Haqq-Misra and Kopparapu use a probabilistic method to determine the feasibility of aliens leaving us clues to their existence. Their work points to the Solar System as a fixed volume and then calculates the percentages of that volume that would need to be thoroughly searched to detect an alien probe or artifact. These searches would have to involve technology able to detect small, foreign objects and then apply it to a smaller portion of the volume to look for results. It’s a study which hasn’t been undertaken so far. We simply cannot say we’ve looked everywhere…

“The surface of the Earth is one of the few places in the Solar System that has been almost completely examined at a spatial resolution of less than 3 feet,” said Haqq-Misra and Kopparapu.

Sure. There are still a lot of nooks and crannies on Earth that haven’t been thoroughly explored – and our oceans are a good example. However, when it comes to searching elsewhere, it’s been a hit-or-miss proposition. While mapping the surface of the Moon, the Lunar Reconnaissance Orbiter is looking at the surface at a resolution of about 20 inches. It may take a few years, but perhaps something isn’t buried under the regolith. As for Mars, chances are slight – but new things seem to be discovered on Mars each day, don’t they? How about the LaGrange points, or the asteroid belt? Things could be hiding there, too.

“Searches to date of the Solar System are sufficiently incomplete that we cannot rule out the possibility that non terrestrial artifacts are present and may even be observing us,” said Haqq-Misra and Kopparapu. They add that “the completeness of our search for non terrestrial objects will inevitably increase as we continue to explore the Moon, Mars and other nearby regions of space.”

After all, what did we expect? E.T. to interrupt a prime time television program to announce their presence? A take-over of the Internet? Maybe each time a meteor makes it to Earth it’s a little calling card that life-possible organisms exists outside our own little sphere…

And maybe somebody needs to drop a bus on us.

Original Story Source: Penn State News Release.

Posted on by Nancy Atkinson

Mars Likely Not Ever Warm and Wet Enough for Life – At Least on Surface

Impact cratering and erosion combine to reveal the composition of the Martian underground by exposing materials from the subsurface. Image credit: NASA/JPL-Caltech/JHUAPL

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Mars’ surface was probably not ever warm and wet long enough to support life, a new study published today in Nature concludes. But underground on the Red Planet might be a different story. By taking a look at several years of data from orbiting spacecraft and examining more than 350 sites on Mars, a team of researchers determined that Martian environments with abundant liquid water on the surface existed only in short episodes. But liquid and likely warm water more likely lasted for longer periods of time below the surface, and this would have been occurring at about the same time that life was developing on Earth.

“If surface habitats were short-term, that doesn’t mean we should be glum about prospects for life on Mars, but it says something about what type of environment we might want to look in,” said Bethany Ehlmann from Caltech and JPL, who is the lead author of the study. “The most stable Mars habitats over long durations appear to have been in the subsurface. On Earth, underground geothermal environments have active ecosystems.”

And so, the best place to look for signs of past life on Mars may be underground.

The researchers’ findings seem to indicate that Mars’ surface was almost always cold and dry, and any appearances of water – and the salts they left behind – occurred during geologically brief periods. This is certainly not the first time research has suggested brief periods of water flowing on Mars, or that underground water may have persisted, but the news study does help to provide a better picture of the history of water on Mars and even if it could possibly be there today.

Clays are crucial to understanding past water on Mars, as they form only when water is around long enough to change the chemical structure of rocks into clay, and different types of clay minerals result from different types of wet conditions.

Signs of deep water, deep life? Erosion has exposed clays (light blue) that subterranean waters favorable to life may have formed eons ago in the Nili Fossae region of Mars. Credit: NASA/JPL/JHUAPL/University of Arizona/Brown University

In 2005, clay minerals were discovered in many regions of Mars by the OMEGA spectrometer on the ESA’s Mars Express. This finding seemed to indicate the planet was once warm and wet. But there’s a problem with Mars’ atmosphere – it is not thick enough now for water to be retained on Mars’ surface, and there is not scientific consensus that it was ever thick enough in the past to have allowed water to remain on the surface.

But this new study supports an alternative hypothesis that warm water persisted under Mars surface and many erosional features seen by the orbiting spacecraft were carved during brief periods when liquid water was stable at the surface.

“The types of clay minerals that formed in the shallow subsurface are all over Mars,” said John Mustard, professor at Brown University in Providence, R.I. Mustard a co-author of the study. “The types that formed on the surface are found at very limited locations and are quite rare.”

During the past five years, researchers used OMEGA and NASA’s Compact Reconnaissance Imaging Spectrometer, or CRISM, instrument on the Mars Reconnaissance Orbiter to identify clay minerals at thousands of locations on Mars. Clay minerals that form with small amounts of water usually retain the same chemical elements as those found in the original volcanic rocks later altered by the water.

The study interprets this to be the case for most terrains on Mars with iron and magnesium clays. In contrast, surface environments with higher ratios of water to rock can alter rocks further. Soluble elements are carried off by water, and different aluminum-rich clays form.

Another clue is detection of a mineral called prehnite. It forms at temperatures above about 400 degrees Fahrenheit (about 200 degrees Celsius). These temperatures are typical of underground hydrothermal environments rather than surface waters.

Two upcoming missions will help decipher the water clues left behind on Mars. The Curiosity rover, or the Mars Science Laboratory will be heading towards Gale Crater, to investigate a large, layered hill that contain clay and sulfate minerals. Curiosity is scheduled to launch later this month.

These new findings also have implications for how Mars’ atmosphere may have evolved over time, and the Mars Atmosphere and Volatile Evolution Mission, or MAVEN, in development for a 2013 launch, may provide evidence for or against this new interpretation of the Red Planet’s environmental history. This new study predicts MAVEN findings will beconsistent with the atmosphere not having been thick enough to provide warm, wet surface conditions for a prolonged period.

Source: JPL