Posted on by Paul Scott Anderson

Do Alien Civilizations Inevitably ‘Go Green’?

Beautiful view of our Milky Way Galaxy. If other alien civilizations are out there, can we find them? Credit: ESO/S. Guisard

[/caption]

In the famous words of Arthur C. Clarke, “Any sufficiently advanced technology is indistinguishable from magic.” This phrase is often quoted to express the idea that an alien civilization which may be thousands or millions of years older than us would have technology so far ahead of ours that to us it would appear to be “magic.”

Now, a variation of that thought has come from Canadian science fiction writer Karl Schroeder, who posits that “any sufficiently advanced technology is indistinguishable from nature.” The reasoning is that if a civilization manages to exist that long, it would inevitably “go green” to such an extent that it would no longer leave any detectable waste products behind. Its artificial signatures would blend in with those of the natural universe, making it much more difficult to detect them by simply searching for artificial constructs versus natural ones.

The idea has been proposed as an explanation for why we haven’t found them yet, based on the premise that such advanced societies would have visited and colonized our entire galaxy by now (known as the Fermi Paradox). The question becomes more interesting in light of the fact that astronomers now estimate that there are billions of other planets in our galaxy alone. If a civilization reaches such a “balance with nature” as a natural progression, it may mean that traditional methods of searching for them, like SETI, will ultimately fail. Of course, it is possible, perhaps even likely, that civilizations much older than us would have advanced far beyond radio technology anyway. SETI itself is based on the assumption that some of them may still be using that technology. Another branch of SETI is searching for light pulses such as intentional beacons as opposed to radio signals.

But even other alternate searches, such as SETT (Search for Extraterrestrial Technology), may not pan out either, if this new scenario is correct. SETT looks for things like the spectral signature of nuclear fission waste being dumped into a star, or leaking tritium from alien fusion powerplants.

Another solution to the Fermi Paradox states that advanced civilizations will ultimately destroy themselves. Before they do though, they could have already sent out robotic probes to many places in the galaxy. If those probes were technologically savvy enough to self-replicate, they could have spread themselves widely across the cosmos. If there were any in our solar system, we could conceivably find them. Yet this idea could also come back around to the new hypothesis – if these probes were advanced enough to be truly “green” and not leave any environmental traces, they might be a lot harder to find, blending in with natural objects in the solar system.

It’s an intriguing new take on an old question. It can also be taken as a lesson – if we can learn to survive our own technological advances long enough, we can ultimately become more of a green civilization ourselves, co-existing comfortably with the natural universe around us.

Posted on by Paul Scott Anderson

600 Million Year Drought Makes Life on Surface of Mars Unlikely

View of Mars' surface near the north pole from the Phoenix lander. Polygon shapes can be seen in the soil. Credit: NASA/JPL-Calech/University of Arizona

[/caption]

Mars is often referred to as a desert world, and for good reason – its surface is barren, dry and cold. While water was abundant in the distant past, it has long since disappeared from the surface, although ice, snow, frost and fog are still common. Other than liquid brines possibly trickling at times, all of Mars’ remaining water is now frozen in permafrost and in the polar ice caps. It has long been thought that the harsh conditions would make current life unlikely at best, and now a new study reaffirms that view.

The results come from continued analysis of the data from the Phoenix lander mission, which landed in the arctic region near the north pole of Mars in 2008. They suggest that Mars has experienced a prolonged drought for at least the past 600 million years.

According to Dr. Tom Pike from Imperial College London, “We found that even though there is an abundance of ice, Mars has been experiencing a super-drought that may well have lasted hundreds of millions of years. We think the Mars we know today contrasts sharply with its earlier history, which had warmer and wetter periods and which may have been more suited to life. Future NASA and ESA missions that are planned for Mars will have to dig deeper to search for evidence of life, which may still be taking refuge underground.”

The team reached their conclusions by studying tiny microscopic particles in the soil samples dug up by Phoenix, which had been photographed by the lander’s atomic-force microscope. 3-D images were produced of particles as small as 100 microns across. They were searching specifically for clay mineral particles, which form in liquid water. The amount found in the soil would be a clue as to how long the soil had been in contact with water. It was determined that less than 0.1 percent of the soil samples contained clay particles, pointing to a long, arid history in this area of Mars.

Since the soil type on Mars appears to be fairly uniform across the planet, the study suggests that these conditions have been widespread on the planet, and not just where Phoenix landed. It’s worth keeping in mind though that soil particles and dust on Mars can be distributed widely by sandstorms and dust devils (and some sandstorms on Mars can be planet-wide in size). The study also implies that Mars’ soil may have only been exposed to liquid water for about 5,000 years, although some other studies would tend to disagree with that assessment.

It should also be noted that more significant clay deposits have been found elsewhere on Mars, including the exact spot where the Opportunity rover is right now; these richer deposits would seem to suggest a different history in different regions. Because of this, and for the other reasons cited above, it may be premature then to extrapolate the Phoenix results to the entire planet, similar soil types notwithstanding. While this study is important, more definitive results might be obtained when physical soil samples can actually be brought back to Earth for analysis, from multiple locations. More sophisticated rovers and landers like the Curiosity rover currently en route to Mars, will also be able to conduct more in-depth analysis in situ.

The Phoenix soil samples were also compared to soil samples from the Moon – the distribution of particle sizes was similar between the two, indicating that they formed in a similar manner. Rocks on Mars are weathered down by wind and meteorites, while on the airless Moon, only meteorite impacts are responsible. On Earth of course, such weathering is caused primarily by water and wind.

As for the life question, any kind of surface dwelling organisms would have to be extremely resilient, much like extremophiles on Earth. It should be kept in mind, however, that these results apply to surface conditions; it is still thought possible that any early life on the planet could have continued to thrive underground, protected from the intense ultraviolet light from the Sun, and where some liquid water could still exist today.

Given Mars’ much wetter early history, the search for evidence of past or present life will continue, but we may have to dig deep to find it.

Posted on by Paul Scott Anderson

New Study Shows How Trace Elements Affect Stars’ Habitable Zones

Comparison of the habitable zone around the Sun in our solar system and around the star Gliese 581. Credit: ESO

[/caption]

Habitable zones are the regions around stars, including our own Sun, where conditions are the most favourable for the development of life on any rocky planets that happen to orbit within them. Generally, they are regions where temperatures allow for liquid water to exist on the surface of these planets and are ideal for “life as we know it.” Specific conditions, due to the kind of atmosphere, geological conditions, etc. must also be taken into consideration, on a case-by-case basis.

Now, by examining trace elements in the host stars, researchers have found clues as to how the habitable zones evolve, and how those elements also influence them. To determine what elements are in a star, scientists study the wavelengths of its light. These trace elements are heavier than the hydrogen and helium gases which the star is primarily composed of. Variations in the composition of these stars are now thought to affect the habitable zones around them.

The study was led by Patrick Young, a theoretical astrophysicist and astrobiologist at Arizona State University. Young and his team presented their findings on January 11, 2012 at the annual meeting of the American Astronomical Society in Austin, Texas. He and his colleagues have examined more than a hundred dwarf stars so far.

An abundance of these elements can affect how opaque a star’s plasma is. Calcium, sodium, magnesium, aluminum and silicon have been found to also have small but significant effects on a star’s evolution – higher levels tended to result in cooler, redder stars. As Young explains, “The persistence of stars as stable objects relies on the heating of plasma in the star by nuclear fusion to produce pressure that counteracts the inward force of gravity. A higher opacity traps the energy of fusion more efficiently and results in a larger radius, cooler star. More efficient use of energy also means that nuclear burning can proceed more slowly, resulting in a longer lifetime for the star.”

The lifetime of a star’s habitable zone can also be influenced by another element – oxygen. Young continues: “The habitable lifetime of an orbit the size of Earth’s around a one-solar-mass star is only 3.5 billion years for oxygen-depleted compositions but 8.5 billion years for oxygen-rich stars. For comparison, we expect the Earth to remain habitable for another billion years or so, for about 5.5 billion years total, before the Sun becomes too luminous. Complex life on Earth arose some 3.9 billion years after its formation, so if Earth is at all representative, low-oxygen stars are perhaps less than ideal targets.”

As well as the habitable zone, the composition of a star can determine the eventual composition of any planets that form. The carbon-oxygen and magnesium-silicon ratios of stars can affect whether a planet will have magnesium or silicon-loaded clay minerals such as magnesium silicate (MgSiO3), silicon dioxide (SiO2), magnesium orthosilicate (Mg2SiO4), and magnesium oxide (MgO). A star’s composition can also play a role in whether a rocky planet might have carbon-based rock instead of silicon-based rock like our planet. Even the interior of planets could be affected, as radiocative elements would determine whether a planet has a molten core or a solid one. Plate tectonics, thought to be important for the evolution of life on Earth, depend on a molten interior.

Young and his team are now looking at 600 stars, ones that are already being targeted in exoplanet searches. They plan to produce a list of the 100 best stars which could have potentially habitable planets.

Posted on by Paul Scott Anderson

How Plants May Have Helped Create Earth’s Unique Landscapes

Credit: Wikimedia Commons

[/caption]

According to conventional thinking, plant life first took hold on Earth after oceans and rivers formed; the soil produced by liquid water breaking down bare rock provided an ideal medium for plants to grow in. It certainly sounds logical, but a new study is challenging that view – the theory is that vascular plants, those containing a transport system for water and nutrients, actually created a cycle of glaciation and melting, conditions which led to the formation of rivers and mud which allowed forests and farmland to later develop. In short, they helped actually create the landscapes we see today.

The evidence was just published in two articles in a special edition of Nature Geoscience.

In the first article, analysis of the data proposes that vascular plants began to absorb the carbon dioxide in the atmosphere about 450 million years ago. This led to a cooling of temperatures on a global scale, resulting in widespread glaciation. As the glaciers later started to melt, they ground up the Earth’s surface, forming the kind of soils we see today.

The second article goes further, stating that today’s rivers were also created by vascular plants – the vegetation broke the rocks down into mud and minerals and then also held the mud in place. This caused river banks to start forming, acting as channels for water, which up until then had tended to flow over the surface much more randomly. As the water was channeled into more specific routes, rivers formed. This led to periodic flooding; sediments were deposited over large areas which created rich soil. As trees were able to take root in this new soil, debris from the trees fell into the rivers, creating logjams. This had the effect of creating new rivers and causing more flooding. These larger fertile areas were then able to support the growth of larger lush forests and farmland.

According to Martin Gibling, a professor of Earth science at Dalhousie University, “Sedimentary rocks, before plants, contained almost no mud. But after plants developed, the mud content increased dramatically. Muddy landscapes expanded greatly. A new kind of eco-space was created that wasn’t there before.”

The new theory also leads to the possibility that any exoplanets that happen to have vegetation would look different from Earth; varying circumstances would create a surface unique to each world. Any truly Earth-like exoplanets might be very similar in general, but the way that their surfaces have been modified might be rather different.

It’s an interesting scenario, but it also raises other questions. What about the ancient river channels on Mars? Some appear to have been formed by brief catastrophic floods, but others seem more similar to long-lived rivers here on Earth, especially if there actually was a northern hemisphere ocean as well. How did they form? Does this mean that rivers could form in a variety of ways, with or without plant life being involved? Could Mars have once had something equivalent to vascular plant life as well? Or could the new theory just be wrong? Then there’s Titan, which has numerous rivers still flowing today. Albeit they are liquid methane/ethane instead of water, but what exactly led to their formation?

From the editorial in Nature Geoscience:

Without the workings of life, the Earth would not be the planet it is today. Even if there are a number of planets that could support tectonics, running water and the chemical cycles that are essential for life as we know it, it seems unlikely that any of them would look like Earth. Even if evolution follows a predictable path, filling all available niches in a reproducible and consistent way, the niches on any Earth analogue could be different if the composition of its surface and atmosphere are not identical to those of Earth. And if evolution is random, the differences would be expected to be even larger. Either way, a glimpse of the surface of an exoplanet — if we ever get one — may give us a whole new perspective on biogeochemical cycling and geomorphology.

Just as the many exoplanets now being found are of a previously unknown and amazingly wide variety, and all uniquely alien, even the ones that (may) support life are likely to be just as diverse from each other as they are from Earth itself. Earth’s “twin” may be out there, but in terms of outward appearance, it may be somewhat more of a fraternal twin than an exact replica.

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

[/caption]

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 Paul Scott Anderson

Key Step in Evolution Replicated by Scientists – With Yeast

Sacharomyces cerevisiae yeast cells. Credit: Wikimedia Commons

[/caption]

One of the great puzzles in science has been the evolution of single-celled organisms into the incredibly wide variety of flora and fauna that we see today. How did Earth make the transition from an initially lifeless ball of rock to one populated only by single-celled organisms to a world teeming with more complex life?

As scientists understand it, single-celled organisms first began evolving into more complex forms more than 500 million years ago, as they began to form multi-cellular clusters. What isn’t understood is just how that process happened. But now, biologists are another step closer figuring out this puzzle, by successfully replicating this key step – using an ingredient common in the making of bread and beer – ordinary Brewer’s yeast (Saccharomyces cerevisiae). While helping to solve evolutionary riddles here on Earth, it also by extension has bearing on the question of biological evolution on other planets or moons as well.

The results were published in last week’s issue of the Journal Proceedings of the National Academy of Sciences (PNAS).

Yeasts are a microscopic form of fungi; they are uni-cellular but can become multi-cellular through the formation of a string of connected budding cells, like in molds. The experiments were based on this fact, and were surprisingly simple, they just hadn’t been done before, according to Will Ratcliff, a scientist at the University of Minnesota (UMN) and a co-author of the paper. “I don’t think anyone had ever tried it before,” he said, adding: “There aren’t many scientists doing experimental evolution, and they’re trying to answer questions about evolution, not recreate it.”

Sam Scheiner, program director in NSF’s Division of Environmental Biology, also adds: “To understand why the world is full of plants and animals, including humans, we need to know how one-celled organisms made the switch to living as a group, as multi-celled organisms. This study is the first to experimentally observe that transition, providing a look at an event that took place hundreds of millions of years ago.”

It’s been thought that the step toward multi-cellular complexity was a difficult one, an evolutionary hurdle that would be very hard to overcome. The new research however, suggests it may not be that difficult after all.

It took the first experiment only 60 days to produce results. The yeast was first added to a nutrient-rich culture, then the cells were allowed to grow for one day. They were then stratified by weight using a centrifuge. Clusters of yeast cells landed on the bottom of the test tubes. The process was then repeated, taking the cell clusters and re-adding them to fresh cultures. After sixty cycles of this, the cell clusters started to look like spherical snowflakes, composed of hundreds of cells.

The most significant finding was that the cells were not just clustering and sticking together randomly; the clusters were composed of cells that were genetically related to each other and remained attached after cell division. When clusters reached “critical mass,” some cells died, a process known as apoptosis, which allows the offspring to separate.

This then, simply put, is the process toward multi-cellular life. As described by Ratcliff, “A cluster alone isn’t multi-cellular. But when cells in a cluster cooperate, make sacrifices for the common good, and adapt to change, that’s an evolutionary transition to multi-cellularity.”

So next time you are baking bread or brewing your own beer, consider the fact that those lowly little yeast cells hold a lot more importance than just a useful role in your kitchen – they are also helping to solve some of the biggest mysteries of how life started, both here and perhaps elsewhere.

Posted on by Amy Shira Teitel

What if the Earth had Two Moons?

The Earth and Moon as seen from Mariner 10 en route to Venus. This could be a similar view of two moons as seen from Earth. Image credit: NASA/courtesy of nasaimages.org

The idea of an Earth with two moons has been a science fiction staple for decades. More recently, real possibilities of an Earth with two moons have popped up. The properties of the Moon’s far side has many scientists thinking that another moon used to orbit the Earth before smashing into the Moon and becoming part of its mass. Since 2006, astronomers have been tracking smaller secondary moons that our own Earth-Moon system captures; these metre-wide moons stay for a few months then leave.

But what if the Earth actually had a second permanent moon today? How different would life be? Astronomer and physicist Neil F. Comins delves into this thought experiment, and suggests some very interesting consequences. 

This shot of Io orbiting Jupiter shows the scale between other moons and their planet. Image credit:NASA/courtesy of nasaimages.org

Our Earth-Moon system is unique in the solar system. The Moon is 1/81 the mass of Earth while most moons are only about 3/10,000 the mass of their planet. The size of the Moon is a major contributing factor to complex life on Earth. It is responsible for the high tides that stirred up the primordial soup of the early Earth, it’s the reason our day is 24 hours long, it gives light for the variety of life forms that live and hunt during the night, and it keeps our planet’s axis tilted at the same angle to give us a constant cycle of seasons.

A second moon would change that.

For his two-mooned Earth thought experiment, Comins proposes that our Earth-Moon system formed as it did — he needs the same early conditions that allowed life to form — before capturing a third body. This moon, which I will call Luna, sits halfway between the Earth and the Moon.

Luna’s arrival would wreak havoc on Earth. Its gravity would tug on the planet causing absolutely massive tsunamis, earthquakes, and increased volcanic activity. The ash and chemicals raining down would cause a mass extinction on Earth.

But after a few weeks, things would start to settle.

Luna would adjust to its new position between the Earth and the Moon. The pull from both bodies would cause land tides and volcanic activity on the new moon; it would develop activity akin to Jupiter’s volcanic moon Io. The constant volcanic activity would make Luna smooth and uniform, as well as a beautiful fixture in the night sky.

New Horizons captured this image of volcanic activity on Io. The same sight could be seen of Luna from Earth. Image credit: NASA/courtesy of nasaimages.org

The Earth would also adjust to its two moons, giving life a chance to arise. But life on a two-mooned Earth would be different.

The combined light from the Moon and Luna would make for much brighter nights, and their different orbital periods will mean the Earth would have fewer fully dark nights. This will lead to different kinds of nocturnal beings; nighttime hunters would have an easier time seeing their prey, but the prey would develop better camouflage mechanisms. The need to survive could lead to more cunning and intelligent breeds of nocturnal animals.

Humans would have to adapt to the challenges of this two-mooned Earth. The higher tides created by Luna would make shoreline living almost impossible — the difference between high and low tides would be measured in thousands of feet. Proximity to the water is a necessity for sewage draining and transport of goods, but with higher tides and stronger erosion, humans would have to develop different ways of using the oceans for transfer and travel. The habitable area of Earth, then, would be much smaller.

The measurement of time would also be different. Our months would be irrelevant. Instead, a system of full and partials months would be necessary to account for the movement of two moons.

A scale comparison of the Earth, the Moon, and Jupiter’s largest moons (the Jovian moons). Image credit:Image Credit: NASA/courtesy of nasaimages.org

Eventually, the Moon and Luna would collide; like the Moon is now, both moons would be receding from Earth. Their eventual collision would send debris raining through Earth’s atmosphere and lead to another mass extinction. The end result would be one moon orbiting the Earth, and life another era of life would be primed to start.

Source: Neil Comins’ What if the Earth had Two Moons? And Nine Other Thought Provoking Speculations on the Solar System.

Posted on by David Warmflash

Phobos-Grunt Predicted to Fall in Afghanistan on January 14

Engineers tuck Phobos-Grunt into the rocket fairing. Credit: Roscosmos

[/caption]

According to a news report in RiaNovosti, Russia’s Phobos-Grunt spacecraft will fall January 14th, “somewhere between 30.7 degrees north and 62.3 degrees east,” placing debris near the city of Mirabad, in southwestern Afghanistan. RiaNovosti said this prediction is according to the United States Strategic Command who calculated the craft will reenter Earth’s atmosphere at 2:22 am.

Editor’s Update: In a call to USSTRATCOM to verify this information, a spokesperson said, “We are not making any statement at USSTRACOM at this time because we are not the lead for this event and cannot make an official statement for any predictions or what is releasable at this time.”

“Please note that the U.S. Strategic Command prediction had a large uncertainty associated with it, i.e., 11 days,” Nicholas L. Johnson, NASA’s Chief Scientist for Orbital Debris told Universe Today in an email. “No one is yet able to predict with confidence the day the Phobos-Grunt will reenter.”


If the probe is predicted to fall on land, this raises the possibility of recovering the Planetary Society’s Living Interplanetary Flight Experiment (LIFE), designed to investigate how life forms could spread between neighboring planets.

The Phobos-Grunt mission profile. Credit: Roscosmos

Carrying about 50 kilograms of scientific equipment, the unpiloted Phobos-Grunt probe was launched November 9th on a mission to the larger of Mars two small moons. Although the Zenit 2 rocket that launched the craft functioned flawlessly, sending Grunt into a low Earth orbit, the upper stage booster, known as Fregat, failed to boost the orbit and send it on a trajectory toward Mars. Thought to have reverted to safe mode, Phobos-Grunt has been flying straight and periodically adjusting her orbit using small thruster engines. While this maneuvering has extended the amount of time that the probe could remain in space before reentering Earth’s atmosphere, ground controllers have been struggling to establish a communication link.

For a while, space commentators considered the possibility that Grunt might be sent on an alternate mission to Earth’s Moon or an asteroid, if control could be restored after the window for a launch to Mars and Phobos was lost. During the past few weeks, the European Space Agency (ESA) started and ended efforts to communicate with the spacecraft on several occasions, but succeeded only twice. Various scenarios were imagined in which aspects of the probe’s mission could be salvaged, despite the serious malfunction that prevented the craft from leaving Earth orbit. But at this point, the only direction for the spacecraft to go is down.

In addition to equipment for making celestial and geophysical measurements and for conduct mineralogical and chemical analysis of the Phobosian regolith (crushed rock and dust), Grunt carries Yinhou-1, a Chinese probe that was to orbit Mars for two years. After releasing Yinhou-1 into Mars orbit and landing on Phobos, Grunt would have launched a return capsule, carrying a 200 gram sample of regolith back to Earth. Also traveling within the return capsule is the Planetary Society’s Living Interplanetary Flight Experiment (LIFE).

The Planetary Society’s Living Interplanetary Flight Experiment (LIFE) capsule, on board the Phobos-Grunt spacecraft. Credit:The Planetary Society

Specifically, LIFE is designed to study the effects of the interplanetary environment on various organisms during a long duration flight in space beyond the Van Allen Radiation Belts, which protect organisms in low Earth orbit from some of the most powerful components of space radiation. Although the spacecraft has not traveled outside of the belts, the organisms contained within the LIFE biomodule will have been in space for more than two months when the probe reenters the atmosphere.

The many tons of toxic fuel are expected to explode high in the atmosphere. However, since the return capsule is designed to survive the heat of reentry and make a survivable trajectory to the ground, it is quite possible that it will reach Afghanistan in one piece. Because the LIFE biomodule is designed to withstand an impact force of 4,000 Gs, it is possible that the experiment can be recovered and the biological samples studied.

To be sure, the possibility of recovering an unharmed returned capsule and LIFE depends on the willingness of the inhabitants around the landing site to allow the Russian Space Agency to pick it up. Given the proximity of the predicted landing area to a war zone and the fact that the Taliban are not known for being enthusiastic about space exploration and astrobiology, it is also possible that a landing on land could turn out no better than a landing over the deepest part of the ocean.

Source: RiaNovosti

Posted on by Paul Scott Anderson

New Study Says Large Regions of Mars Could Sustain Life

The Planet Mars. Image credit: NASA
The Planet Mars. Image credit: NASA

[/caption]

The question of whether present-day Mars could be habitable, and to what extent, has been the focus of long-running and intense debates. The surface, comparable to the dry valleys of Antarctica and the Atacama desert on Earth, is harsh, with well-below freezing temperatures most of the time (at an average of minus 63 degrees Celsius or minus 81 Fahrenheit), extreme dryness and a very thin atmosphere offering little protection from the Sun’s ultraviolet radiation. Most scientists would agree that the best place that any organisms could hope to survive and flourish would be underground. Now, a new study says that scenario is not only correct, but that large regions of Mars’ subsurface could be even more sustainable for life than previously thought.

Scientists from the Australian National University modeled conditions on Mars on a global scale and found that large regions could be capable of sustaining life – three percent of the planet actually, albeit mostly underground. By comparison, just one percent of Earth’s volume, from the central core to the upper atmosphere, is inhabited by some kind of life. They compared pressure and temperature conditions on Earth to those of Mars to come up with the surprising results.

According to Charley Lineweaver of ANU, “What we tried to do, simply, was take almost all of the information we could and put it together and say ‘is the big picture consistent with there being life on Mars?’ And the simple answer is yes… There are large regions of Mars that are compatible with terrestrial life.”

So it seems that while, as we know, the surface of Mars is quite inhospitable to most forms of life (that we know of) except perhaps for some extremophiles, conditions underground are a different matter. It is already known that there are vast deposits of ice below the surface even near the equator (as well as the polar ice caps of course), so there could be liquid water a bit deeper where it is warmer. Those conditions would be ideal for bacteria or other simple organisms. While that idea has been proposed and discussed before, Lineweaver’s findings support it on a planet-wide basis – previous studies tended to focus on specific locations in a “piecemeal” approach, but these new ones take the entire planet into consideration.

The paper is currently available for free here. Abstract:

We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of *310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the *5km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to *3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life. Key Words: Biosphere—Mars— Limits of life—Extremophiles—Water. Astrobiology 11, xxx–xxx.

Posted on by Paul Scott Anderson

The Habitable Exoplanets Catalog is Now Online!

Credit: The Habitable Exoplanets Catalog, Planetary Habitability Laboratory @ UPR Arecibo (phl.upl.edu)

[/caption]

Anyone who has an interest in exoplanets probably knows about the various online catalogs that have become available in recent years, such as The Extrasolar Planets Encyclopaedia for example, providing up-to-date information and statistics on the rapidly growing number of worlds being discovered orbiting other stars. So far, these have been listings of all known exoplanets, both candidates and confirmed. But now there is a new catalog published by the Planetary Habitability Laboratory (a project of the University of Puerto Rico at Arecibo), which focuses exclusively on those planets which have been determined to be potentially habitable. The Habitable Exoplanets Catalog is a database which will serve as a key resource for scientists and educators as well as the general public.

As of right now, there are two confirmed planets and fourteen candidates listed, but those numbers are expected to grow over the coming months and years as more candidates are found and more of those candidates are confirmed. There is even a listing of habitable moons, whose existence have been inferred from the data, although none have been observed yet (finding exoplanets is challenging enough, but exomoons even more so!).

According to Abel Méndez, Director of the PHL and principal investigator, “One important outcome of these rankings is the ability to compare exoplanets from best to worst candidates for life.” He adds: “New observations with ground and orbital observatories will discover thousands of exoplanets in the coming years. We expect that the analyses contained in our catalog will help to identify, organize, and compare the life potential of these discoveries.”

The big question of course is whether any habitable planets are actually inhabited, two different things. To help answer that, it will be necessary to further analyze the atmospheres and surfaces of those planets, looking for any indication of possible biosignatures such as oxygen or methane. Kepler can’t do that directly, but subsequent telescopes such as the Terrestrial Planet Finder (TPF) will be able to, and provide a more accurate assessment of their physical composition, climate, etc.

Not long ago it wasn’t known if there even were any planets orbiting other stars; now we’re finding them by the thousands and soon we’ll be able to distinguish their unique physical characteristics and have a better idea of how many habitable worlds are out there – exciting times.