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Nitrogen fingerprint in biomolecules could be from early sun

No need for extrasolar delivery by comet

Pairs of nitrogen atoms are more likely to be split by UV light from the Sun and other sources if one or both are the heavier isotope nitrogen-15. In this experiment those heavier atoms combined with hydrogen to form ammonia. Credit: UC San Diego

Pairs of nitrogen atoms are more likely to be split by UV light from the Sun and other sources if one or both are the heavier isotope nitrogen-15. In this experiment those heavier atoms combined with hydrogen to form ammonia. Credit: UC San Diego

Chemical fingerprints of the element nitrogen vary by extremes in materials from the molecules of life to the solar wind to interstellar dust. Ideas for how this great variety came about have included alien molecules shuttled in by icy comets from beyond our solar system and complex chemical scenarios.

New experiments using a powerful source of ultraviolet light have shown that no extra-solar explanation is needed and the chemistry is straight forward, scientists from the University of California, San Diego, Hebrew University and UCLA report in the early online edition of the Proceedings of the National Academy of Sciences the week of September 29.

Nitrogen occurs in two stable forms. Nitrogen-14, with an equal number of protons and neutrons in its nucleus, is most abundant. Nitrogen-15, with an extra neutron, is far more rare, but biological molecules like proteins have larger proportions; they’re enriched in nitrogen-15 relative to the nitrogen gas in Earth’s atmosphere. And Earth’s atmosphere itself has relatively more nitrogen-15 than other sources, such as the solar wind and Jupiter’s atmosphere.

Samples from the icy comet Wild 2, retrieved by NASA’s Stardust mission, and several kinds of meteorites also have relatively more nitrogen-15, and within the inhomogenous mix that makes up stony meteorites are inclusions, individual crystals that can have extremely high proportions of nitrogen-15. These observations led to the idea that the building blocks of life could have been ‘seeded’ on Earth, delivered perhaps by comet.

The new experiments render that hypothesis unnecessary. “We can generate this nitrogen enrichment inside the solar system. You can form all these building blocks of life inside our solar system. You don’t have to bring the pieces in from outside,” said Subrata Chakraborty, a project scientist in chemistry at UC San Diego and lead author of the report.

By shining a bright beam of very short wave ultraviolet light through nitrogen and hydrogen gas, Chakraborty and colleagues generated ammonia with drastically skewed ratios of nitrogen-15 relative to that found in the initial gas, which matched that of Earth’s atmosphere. Pairs of nitrogen atoms — the molecules of the gas — were more likely to be split by UV photons if one or both atoms are the heavier version. Those freed nitrogen atoms recombined with hydrogen to form ammonia.

Ammonia molecules, a nitrogen atom bound to three hydrogen atoms, makes up a fundamental chemical group, the ‘amines’ the characterize amino acids, which link up in long chains to form proteins. They also join aromatic rings of carbon to form nitrogenous bases, the information carrying components of DNA and RNA. And RNA is how many think life got its start.

Light like this, with wavelengths this short, doesn’t make it to Earth anymore. It’s deflected by Earth’s atmosphere. In fact, the experiments took place in a custom-engineered vacuum chamber aligned with the Lawrence Berkeley National Laboratory’s Advanced Light Source synchrotron and were a challenge to pull off.

The chemical events that produced amines with extra nitrogen-15 would have happened long ago, probably in the icy outer reaches of the early solar nebula said Mark Thiemens, professor of chemistry at UC San Diego who directed the work. “It’s the right time for this to have happened: before planets, before life.”

Image of patchy wrinkle structures from an outcrop. Ridge (upper right corner) and Pit (center) wrinkle structures are present on the same bedding plane. Swiss Army knife for scale. The location is the Upper Cambrian Big Cove Member of the Petit Jardin Formation, near Marches Point on the Port au Port Peninsula in western Newfoundland. Credit: Image courtesy of Giulio Mariotti

Life’s Wrinkles in the Sand

The total width of the image is 30 cm. Credit: Mariotti et al. 2014

Wrinkle structures reproduced in the laboratory​. by moving microbial aggregates on a bed of loose fine sand.
The total width of the image is 30 cm. Credit: Mariotti et al. 2014

A new study shows how wrinkle structures can form on a bed of sand when waves and microorganisms are present. Wrinkle structures on sandy bed surfaces are rare on Earth today, but were more common in ancient sedimentary environments. These ancient sediments often have trace fossils and imprints of early animals, and appear in the geological record after some of the largest mass extinctions on Earth.

Some scientists have theorized that wrinkle structures are the remnants of dense colonies of microbes known as microbial mats, but the new study proposes a different origin.

In their experiment, researchers placed microbial aggregates on bare sand in a wave tank. Microbial mats are dense colonies of microorganisms that are often many layers thick and attached to a surface. Microbial aggregates are basically broken-up pieces of microbial mats, which are produced when the mats are damaged in events like storms or strong currents. Animals that feed on microbial mats also help break them apart, making them more susceptible to storms and helping to produce free-floating microbial aggregates.

The team showed that the wrinkle structures are formed in the interaction between microbial aggregates and sandy sediments when waves are present. The waves do not move sand grains directly. Instead, they act on the microbial aggregates to produce these features. Aggregates of microorganisms (about a millimeter in size) are pushed around by waves, which results in the formation of features like ridges and pits.

The team concluded that wrinkle structures are indeed biosignatures (signs of life’s presence), but that they form when microorganisms are present at the interface between sediment and waves, and not beneath microbial mats.

Image of patchy wrinkle structures from an outcrop. Ridge (upper right corner) and Pit (center) wrinkle structures are present on the same bedding plane. Swiss Army knife for scale. The location is the Upper Cambrian Big Cove Member of the Petit Jardin Formation, near Marches Point on the Port au Port Peninsula in western Newfoundland. Credit: Image courtesy of Giulio Mariotti

Image of patchy wrinkle structures from an outcrop. Ridge (upper right corner) and Pit (center) wrinkle structures
are present on the same bedding plane. Swiss Army knife for scale. The location is the Upper
Cambrian Big Cove Member of the Petit Jardin Formation, near Marches Point on the Port au
Port Peninsula in western Newfoundland. Credit: Image courtesy of Giulio Mariotti


 

For more details on the study, Astrobiology Magazine spoke with lead author Giulio Mariotti of the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology (MIT) and co-author Tanja Bosak, Professor in Earth, Atmospheric and Planetary Sciences at MIT.

Astrobiology Magazine (AM): What is the difference between a microbial mat, a biofilm, and a microbial aggregate?

Mariotti: A biofilm is composed by many different microorganisms embedded in a gel-like substance and attached to a surface. A microbial mat is like a biofilm, but thicker (> 1mm) and vertically stratified. A microbial aggregate is a round-shaped, mm-size piece of a microbial mat.

AM: Wrinkle structures on sandy bed surfaces are rare on Earth today, but where are they found? Do wrinkle structures form on other surfaces?

Bosak: They are found in some coastal environments, but they do not last long, so there are very few reports of modern wrinkle structures. Our mechanism takes only a couple of hours to form these structures, so it would be hard to see them form in real time, and they can be easily destroyed. This is party because they can be destroyed by burrowing animals (which were not abundant during the time when wrinkle structures were very common), and partly because they are easily destroyed by stronger storms.

These structures only form on sandy and silty surfaces (i.e., grain sizes from ~ 0.1-0.25 mm).

AM: Where can ancient wrinkle structures found today?

Mariotti: Newfoundland (Canada), Death Valley (USA), Australia, India, and South Africa.

AM: Could you observe the formation of wrinkle structures in nature, or is it simply too difficult because they form so quickly (and are also quickly destroyed)?

Mariotti: We predict that wrinkles structures should form in water depth of about 10-100 m in the continental shelf, that is, in front of a beach facing the Ocean. Testing this mode would require us to dive, deliver some fragments of microbial mats, and wait for the right wave conditions to form the wrinkle structures. Alternatively the experiment might be attempted in water depth less than a meter in a protected environment, such as a sandy lagoon.

AM: Why were ancient wrinkle structures so much more prevalent (why were they not destroyed before being preserved in the rock record)?

Mariotti: Ancient wrinkle structures were more prevalent because microbial aggregates were more common in the past, especially during the time were only a small amount of grazers were present. However, it is also true that the growth of microbial mats on top of already formed wrinkle structures helped preserving them in the rock record, as microbial mats were more common in the past.

The study was supported in part by the NASA Astrobiology Institute and published in the journal Nature Geosciences.

This image is a composite of several images taken during two separate Titan flybys on Oct. 9 (T19) and Oct. 25 (T20). Credit: (NASA/JPL/University of Arizona)

Cassini Watches Mysterious Feature Evolve in Titan Sea

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn’s moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell

NASA’s Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn’s moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini’s radar experiment, but its appearance changed between the two apparitions.

Images of the feature taken during the Cassini flybys are available at:

http://photojournal.jpl.nasa.gov/catalog/PIA18430

The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini’s July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini’s infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini’s flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.

Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.

The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.

The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon’s northern hemisphere. Monitoring such changes is a major goal for Cassini’s current extended mission.

“Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan,” said Stephen Wall, the deputy team lead of Cassini’s radar team, based at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re hopeful that we’ll be able to continue watching the changes unfold and gain insights about what’s going on in that alien sea.”

A visualization of a protein's structure. Credit: Ken Downing, UC Berkeley and LBNL

Back from the Dead: Scientists “Resurrect” Ancient Proteins to Learn about Primordial Life on Earth

The young Earth differed markedly from today's world. Credit: NASA

The young Earth differed markedly from today’s world. Credit: NASA

Geological evidence tells us that ancient Earth probably looked and felt very different from the planet we all recognize today. Billions of years ago, our world was a comparatively harsh place. Earth likely had a hotter climate, acidic oceans and an atmosphere loaded with carbon dioxide. The fact that manmade climate change, through carbon dioxide pollution, is re-introducing such hotter, acidified conditions demonstrates their intertwinement.

More recently, the life sciences have begun buttressing these notions of primordial Earth. Thanks to advances in a niche field called paleobiochemistry, researchers in the last decade have started to “resurrect” ancient proteins. Studying these proteins’ properties is offering us glimpses of what life was like in bygone epochs.

The results so far are compelling. Take, for example, beta lactamase proteins, which first evolved between 2 to 3 billion years ago. These ancient proteins actually remain more stable and work better in hot spring-like temperatures of between 130 and 150 degrees Fahrenheit (54 and 66 degrees Celsius) compared to their modern counterparts. Other proteins, called thioredoxins, originated 4 billion years ago at the time of life’s origin, and these ancient proteins stay active in acidities that would break down many modern proteins. Findings of this sort help paint a portrait of life prior to 500 million years ago in the vast era known as the Precambrian.

“Molecular resurrection studies provide a new line of evidence supporting geological models that suggest that the Precambrian Earth hosted a hotter and more acidic ocean than its modern counterpart,” Eric Gaucher, a pioneering paleobiochemist and a professor biology at Georgia Tech. “Early life was adapted to this environment.”

Paleobiochemistry should have much more to eventually say on this topic. Toward this end, Gaucher and colleagues at the University of Granada in Spain have a new paper in the June 2014 issue of the scientific journal Proteins: Structure, Function, and Bioinformatics. The study compares two common techniques used in paleobiochemistry that have potential biotechnology applications, such as finding ways of dealing with the scourge of antibiotic resistance. The two methods allow scientists to extrapolate the composition of proteins from eons ago.

Deciphering the development of biota on Earth is important not only for piecing together our planet’s past — and thus its potential future — but also for gauging where else life might arise in the cosmos.

“Knowing how life originated and diversified on early Earth provides us with a perspective on the conditions that support primitive life,” said Gaucher. “This information can better inform our decisions to search for life on other planets.”

Breathing new life into old proteins

Living creatures use proteins for much of life’s business. These molecules form many of the structural components of cells and facilitate the chemistry for powering them. Made from combinations of any of 20 amino acid building blocks, proteins come in an almost endless variety of complexity and function.

A visualization of a protein's structure. Credit: Ken Downing, UC Berkeley and LBNL

A visualization of a protein’s structure. Credit: Ken Downing, UC Berkeley and LBNL

“It is remarkable to think that there are billions of different proteins contained within all organisms on modern Earth,” said Gaucher. “Yet, these proteins are composed of the same building blocks, only arranged in different configurations or sequences.”

Researchers have compiled huge databases full of the proteins’ amino acid sequences. The sequences have changed over evolutionary history. By comparing today’s sequences to each other, scientists can get a good idea of the sequence of an ancestral protein from which the modern versions descended.

The concept is rather like that of tracing modern languages back to older, source languages, as Gaucher has previously explained to Astrobiology Magazine. By comparing several European languages, for instance, one would discern that French, Italian, Portuguese, Romanian and Spanish all have clear Latin roots.

“Molecular resurrection studies use a top-down method, whereby modern biological information is used to infer ancient biology,” said Gaucher. “Studying this ancient biology gets us closer to the origins of life itself.”

A consensus approach

One method is called consensus-sequence engineering, and is the more simplistic of the two. Scientists just plug the sequence of a protein of interest into a protein database. The query returns a large number of “hits,” or analogous sequences.

“These sequences likely correspond to modern proteins that are evolutionarily related to the query protein,” said Valeria Risso, lead author of the new Proteins paper and a chemist at the University of Granada.

From there, Risso and colleagues gather statistics on the particular amino acids that appear at corresponding positions on the analogous proteins. Whichever amino acid pops up most frequently is deemed the “consensus” amino acid.

In theory, this consensus amino acid had previously occurred at the sequence location earlier on in evolutionary history, before mutations led to divergent, modern sequences. This makes sense, because nature is conservative. Evolution should favor keeping a sequence that works versus a mutated one that doesn’t. Every now and then, of course, a mutation will “earn its keep” by providing the organism with an advantage or — at the very least — not hinder its possessor from reproducing.

The consensus-seeking task is completed for every amino acid position. The next step: artificially generating the consensus protein in the lab. This is done by introducing a modified gene into a model organism, such as the bacterium E. coli. The organisms handily cranks out the protein through natural means. The new, yet old-fangled protein can then be put through its paces by seeing how it chemically reacts in certain conditions.

Tree of life

The second method more closely follows the historical linguist analogy. It involves creating what is known as a phylogenetic tree. Essentially, the protein sequences are compared, as before, but they go through an evolutionary model-based analysis to search for “nodes,” or branching points.

A phylogenetic tree of life. Credit: Wikimedia Commons

A phylogenetic tree of life. Credit: Wikimedia Commons

The nodes’ sequences represent the last common ancestor for the species that subsequently split off, on down to modernity. Another way to think of this phylogenetic tree method is that it is essentially a genealogy.

The node sequences are inferred and compiled. The proteins encoded by the reconstructed sequences are then synthesized in the laboratory — “laboratory resurrection,” as it’s called. The protein, as with consensus-sequence engineering, is produced by a model organism and its properties are then assessed.

Hopefully, the resulting protein’s properties, when compared to its descendant proteins, should fit like a link in a logical evolutionary chain.

“These properties are expected to ‘tell’ a story that makes sense in biological terms by providing a convincing evolutionary narrative,” said Gaucher.

An example of this proteinaceous storytelling: the fact that ancient proteins, as mentioned before, seem optimized for the high-heat, high-acidity environmental conditions which geology suggests characterized the young Earth.

Both paleobiochemistry techniques seek to restore proteins long lost through the vicissitudes of evolution. But is the consensus technique as good at recovering “real” primordial proteins as the phylogenetic approach? The new paper aimed to answer this question.

Dueling time machines

Visualizations of two different beta-lactamase protein structures. The orange structure is from Yersinia pestis, the pathogen that causes plague, and the green is from Escherichia coli. Credit: Center for Structural Genomics of Infectious Diseases/NIAID

Visualizations of two different beta-lactamase protein structures. The orange structure is from Yersinia pestis, the pathogen that causes plague, and the green is from Escherichia coli. Credit: Center for Structural Genomics of Infectious Diseases/NIAID

The researchers compared properties of a beta lactamase protein yielded from consensus sequence and phylogenetic sequence methods. Beta lactamase is a primary means of antibiotic resistance. It allows an organism to persevere against the lactam class of antibiotics; we rely on numerous lactam drugs, such as penicillin, to fight off infections.

Three consensus variants were created for the study. Sequence-wise, they were indeed quite like the sequences made by the more rigorous, phylogenetic approach.

However, the consensus-sequence derived proteins were not as stable as the phylogenetic proteins. Nor did they partner up with as many other relevant molecules. This is a trending trait of ancient proteins, which according to theory, started out as generalists, then honed and specialized over the course of evolution. Though the consensus sequence proteins differed by just a few amino acids, important differences in functionality followed.

Overall, consensus engineering does not look like the best way to work backwards toward discovering how ancient life worked, either from a biotechnology or an astrobiology standpoint.

“Consensus certainly remains an interesting approach in protein engineering,” said paper-coauthor Jose M. Sanchez-Ruiz, also a chemist at the University of Granada. Nevertheless, Sanchez-Ruiz added, the study’s “results support ancestral reconstruction and resurrection as a more efficient procedure to obtain proteins with extreme and useful properties.”

Life, decoded

Learning more about primordial life will open up a lot of avenues for science. On a fundamental level, reconstructing life back through the ages gets us more familiar with the parts and pieces biology requires.

A cross-section of a subsurface "lake" on Europa. A vast, salty ocean is thought to exist under Europa's icy crust. The lake suggests the surface and subsurface could be interacting, transferring nutrients and energy. Credit: Britney Schmidt/Dead Pixel VFX/Univ. of Texas at Austin

A cross-section of a subsurface “lake” on Europa. A vast, salty ocean is thought to exist under Europa’s icy crust. The lake suggests the surface and subsurface could be interacting, transferring nutrients and energy. Credit: Britney Schmidt/Dead Pixel VFX/Univ. of Texas at Austin

“Analogous to the engineering adage that you cannot understand something unless you can build it, a fuller understanding of life will only come when we can build life,” said Gaucher.

Gauging what sorts of ingredients and environments were conducive to life forming on Earth will inform astrobiological ambitions. Knowing what to look for on future missions to potential places for life, like Jupiter’s moon Europa, will be one benefit of a more complete picture of early Earth’s microbes.

Better yet than toying with individual proteins, though, would be sizing up a whole organism. And stay tuned: by building on their success with phylogenetics, Gaucher and colleagues hope to be able to bring ancient bacteria and archaea back from the dead.

“Although the majority of resurrection studies currently focus on resurrecting one or two protein families at a time,” Gaucher said, “we anticipate that we will be able to resurrect a complete ancestral genome in the near future and jump-start this genome using modern life to, in essence, resurrect long extinct forms of life.”

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Turning the Moon into a cosmic ray detector

Artists rendition of the SKA. Credit: SKA Organisation

Artists rendition of the SKA. Credit: SKA Organisation

Scientists from the University of Southampton are to turn the Moon into a giant particle detector to help understand the origin of Ultra-High-Energy (UHE) cosmic rays – the most energetic particles in the Universe.

The origin of UHE cosmic rays is one of the great mysteries in astrophysics. Nobody knows where these extremely rare cosmic rays come from or how they get their enormous energies. Physicists detect them on Earth at a rate of less than one particle per square kilometre per century.

Dr Justin Bray, a Research Fellow in Cosmic Magnetism at the University of Southampton, is lead author of a proposal to use the Square Kilometre Array (SKA), set to become the largest and most sensitive radio telescope in the world, to detect vastly more UHE cosmic rays by using the Moon as a giant cosmic ray detector.

On Earth, physicists detect these high-energy particles when they hit the upper atmosphere triggering a cascade of secondary particles that generate a short and faint burst of radio waves only a few nanoseconds long.

It is this signal that astronomers hope to pick up from the Moon, but as these signals are so short and faint no radio telescope on Earth is currently capable of picking them up.

With its large collecting area and high sensitivity, the SKA will be able to detect these signals using the visible lunar surface – millions of square kilometres – giving the researchers access to more data about UHE cosmic rays than they have ever had before.

The Galileo spacecraft sent back this image of the Moon as it headed into the outer solar system. Credit: NASA

The Galileo spacecraft sent back this image of the Moon as it headed into the outer solar system. Credit: NASA

The current largest detector on Earth is the Pierre Auger Observatory in Argentina that covers an area of 3,000 square kilometres, about the size Luxembourg. The SKA will be more than 10 times larger (33,0000 square kilometres) and researchers hope to detect around 165 UHE cosmic rays a year from the Moon compared to the 15-a-year currently observed.

Dr Bray announced details of the project at a major SKA conference in Italy. He says: “Cosmic rays at these energies are so rare that you need an enormous detector to collect a significant number of them – but the moon dwarfs any particle detector that has been built so far. If we can make this work, it should give us our best chance yet to figure out where they’re coming from.”

Dr Bray is working with Professor Anna Scaife, also from Physics and Astronomy at the University of Southampton, who leads the development of the SKA’s Imaging Pipeline as part of the Science Data Processor (SDP) work package consortium.

Professor Scaife says: “Defining science goals for the telescope is crucial for ensuring that the appropriate technical capabilities are considered during the design phase.”

Using a network of radio antennas in the Southern hemisphere, the SKA will advance our understanding of how the Universe evolved and challenge Einstein’s theory of relativity. With receivers across Australia and Africa, its dishes and antennas will provide detailed information on the large scale 3D structure of the Universe.

When operational in the early 2020’s, the SKA radio telescope will produce more than 10 times the current global traffic of the Internet in its internal telecommunications system. To play back a single day’s worth of SKA data on an MP3 player would take about two million years.

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New molecule found in space connotes life origins

The vibrant, starry stream of the Milky Way frames radio telescopes of the Atacama Large Millimeter/submillimeter Array - known as the ALMA Observatory - in Chile’s Atacama Desert.

The vibrant, starry stream of the Milky Way frames radio telescopes of the Atacama Large Millimeter/submillimeter Array – known as the ALMA Observatory – in Chile’s Atacama Desert.

Hunting from a distance of 27,000 light years, astronomers have discovered an unusual carbon-based molecule – one with a branched structure – contained within a giant gas cloud in interstellar space.

Like finding a molecular needle in a cosmic haystack, astronomers have detected radio waves emitted by isopropyl cyanide. The discovery suggests that the complex molecules needed for life may have their origins in interstellar space.

Using the Atacama Large Millimeter/submillimeter Array, known as the ALMA Observatory, a group of radio telescopes funded partially through the National Science Foundation, researchers studied the gaseous star-forming region Sagittarius B2.

Astronomers from Cornell, the Max Planck Institute for Radio Astronomy and the University of Cologne (Germany) describe their discovery in the journal Science (Sept. 26.)

Organic molecules usually found in these star-forming regions consist of a single “backbone” of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making it the first interstellar detection of such a molecule, says Rob Garrod, Cornell senior research associate at the Center for Radiophysics and Space Research.

This detection opens a new frontier in the complexity of molecules that can be formed in interstellar space and that might ultimately find their way to the surfaces of planets, says Garrod. The branched carbon structure of isopropyl cyanide is a common feature in molecules that are needed for life – such as amino acids, which are the building blocks of proteins. This new discovery lends weight to the idea that biologically crucial molecules, like amino acids that are commonly found in meteorites, are produced early in the process of star formation – even before planets such as Earth are formed.

Rob Garrod, Cornell senior research associate at the Center for Radiophysics and Space Research.

Garrod, along with lead author Arnaud Belloche and Karl Menten, both of the Max Planck Institute for Radio Astronomy, and Holger Müller, of the University of Cologne, sought to examine the chemical makeup of Sagittarius B2, a region close to the Milky Way’s galactic center and an area rich in complex interstellar organic molecules.

With ALMA, the group conducted a full spectral survey – looking for fingerprints of new interstellar molecules – with sensitivity and resolution 10 times greater than previous surveys.

The purpose of the ALMA Observatory is to search for cosmic origins through an array of 66 sensitive radio antennas from the high elevation and dry air of northern Chile’s Atacama Desert. The array of radio telescopes works together to form a gigantic “eye” peering into the cosmos.

“Understanding the production of organic material at the early stages of star formation is critical to piecing together the gradual progression from simple molecules to potentially life-bearing chemistry,” said Belloche.

About 50 individual features for isopropyl cyanide (and 120 for normal-propyl cyanide, its straight-chain sister molecule) were identified in the ALMA spectrum of the Sagittarius B2 region. The two molecules – isopropyl cyanide and normal-propyl cyanide – are also the largest molecules yet detected in any star-forming region.

Ancient ocean currents may have changed pace and intensity of ice ages. About 950,000 years ago, North Atlantic currents, Northern Hemisphere ice sheets underwent changes. Credit: NASA

Our Ocean’s Cosmic Origin

Ancient ocean currents may have changed pace and intensity of ice ages. About 950,000 years ago, North Atlantic currents, Northern Hemisphere ice sheets underwent changes. Credit: NASA

Ancient ocean currents may have changed pace and intensity of ice ages. About 950,000 years ago, North Atlantic currents, Northern Hemisphere ice sheets underwent changes. Credit: NASA

Most of the Earth’s surface is covered in water, half of which may be older than the Sun itself.

The origin of the Earth’s water – the source of life on our planet and likely off of it – is a wellspring of debate. For a long time, our abundant oceans were attributed to comets, which may have delivered water to the surface after our planet cooled. Recently, astronomers at JPL concluded that comets are an unlikely source for the oceans, leaving asteroids or even small planets at the outskirts of the solar system as the top contenders for water delivery to early Earth. However, that doesn’t answer the more fundamental question: where did that water come from?

“We sought to understand where the water in comets and elsewhere came from originally,” said astronomer Ilse Cleeves, lead author on the paper in Science. “The Earth likely formed ‘dry’ – without water initially – but was later supplied with water ice by asteroids and perhaps some amount of cometary material. We wanted to understand where that reservoir of water originated.”

The cosmic origin of Earth’s water came to light after Cleeves, whose work focuses on the molecules the make up the Solar System, met cosmochemist Conel Alexander. Alexander studies asteroids that have fallen to Earth in order to understand the materials that make up the galaxy. Together, Cleeves and Alexander went on a quest to sort out the origin of the Solar System’s H20 – which, it turns out, is more like HDO.

Normal hydrogen, H, is a lonely proton. Heavy hydrogen, D, is a proton and a neutron. When heavy hydrogen joins with oxygen, the result is heavy water, HDO. According to Cleeves’ results, there is more HDO in comets and on Earth than can be accounted for by the formation of our planetary disk.

“The clue here,” said Alexander, “is the D/H ratio of the water. The D/H ratio of water in comets, meteorites, the Earth, Saturn’s Moons Enceladus and Titan are all much more deuterium-rich that the bulk solar composition.”

An illustration of water in our Solar System through time from before the Sun’s birth through the creation of the planets. The image is credited to Bill Saxton, NSF/AUI/NRAO

An illustration of water in our Solar System through time from before the Sun’s birth through the creation of the planets. The image is credited to Bill Saxton, NSF/AUI/NRAO

This ratio of heavy hydrogen to light hydrogen (D/H) in various places throughout the Solar System allowed Cleeves and Alexander to make a model of our water’s origin that explains what we see today when we study oceans, asteroids and comets. The model hinges on an important difference: where heavy water should be found versus where it actually is found.

Extremely cold temperatures like those at the edge of Solar System drive the formation of heavy water, while warmer climates near the planets leave the odds of finding light water, H20, much higher. According to Cleeves, strong solar winds should have shielded large portions of the coalescing Solar System, making the formation of heavy water near Earth and the gas giants much less likely. Yet, when we look, the heavy water is here, there and everywhere. The conclusion: our heavy water didn’t arise from the same disk that gave rise to the Sun, but rather travelled here from afar.

“We found that there simply weren’t enough energetic ionizing sources in the cold gas of disks to synthesize heavy water,” said Cleeves, “It had to have come from elsewhere, and the only other source is the cold interstellar gas that formed the Sun. “

By starting with an estimate of how much heavy water could have formed around our young Sun and moving forward in time, Alexander and Cleeves’ model proved that some, if not a majority, of our water didn’t come from around here.

“We estimated that ≥7 % and as much as 30-50% of the Earth’s water could have been interstellar,” said Alexander, “while for comets it is ≥14% and as high as 100%.”

How and when heavy water that pre-dates the Solar System travelled here has yet to be determined, but some good data may soon emerge. In a few weeks time, the Rosetta mission is set to directly sample a comet with its lander Philae. If that mission succeeds, before the year is out we may have direct evidence of how much HDO a comet contains. This will hone our understanding the predictive native of models like Cleeves’ and Alexanders’. For now, estimates provided by their paper suggest that perhaps all of the water in comets is cosmic – derived from molecular clouds in-between solar systems, rather than local in origin.

Looking at the ratio of hydrogen to its heavy isotope deuterium in ocean water and other more exotic samples such as comets and meteorites, can help scientists learn about the water on our planet's origin. Credit: Photo of the California coast by Carnegie President Matthew Scott

Looking at the ratio of hydrogen to its heavy isotope deuterium in ocean water and other more exotic samples such as comets and meteorites, can help scientists learn about the water on our planet’s origin. Credit: Photo of the California coast by Carnegie President Matthew Scott

So what does this mean for life outside the Solar System?

“It is remarkable that water survived the entire process of stellar birth,” Cleeves told Astrobio, “to then be incorporated into the planetary bodies in the solar system,”

As Alexander sees it, so much water surviving the birth of our Sun improves the odds of life evolving elsewhere in the Universe.

“Since the Solar System seems fairly typical, this indicates that some interstellar water and organic matter would survive the formation of most solar systems,” Alexander told Astrobio.

“Many people have speculated that the organic matter in comets and asteroids helped kick start life. If that organic material had an interstellar heritage, then most forming planetary systems who have had that same ‘soup’ of organic material available.”

This research was supported by the NSF, the Rackham Predoctoral Fellowship, NASA Astrobiology, NASA Cosmochemistry and NASA.

 

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Antifreeze proteins in Antarctic fish prevent both freezing and melting

Antarctic fish that manufacture their own “antifreeze” proteins to survive in the icy Southern Ocean also suffer an unfortunate side effect, researchers funded by the National Science Foundation (NSF) report: The protein-bound ice crystals that accumulate inside their bodies resist melting even when temperatures warm.

A notothenioid fish in Antarctic ice. "Antifreeze" in its blood protects in the frigid waters. Credit: Paul A. Cziko, University of Oregon

A notothenioid fish in Antarctic ice. “Antifreeze” in its blood protects in the frigid waters. Credit: Paul A. Cziko, University of Oregon

“We discovered what appears to be an undesirable consequence of the evolution of antifreeze proteins in Antarctic notothenioid fish,” said University of Oregon doctoral student Paul Cziko, who led the research with University of Illinois animal biology professors Chi-Hing “Christina” Cheng and Arthur DeVries. “What we found is that the antifreeze proteins also stop internal ice crystals from melting. That is, they are anti-melt proteins as well.”

The new finding was reported in the Proceedings of the National Academy of Sciences.

Five families of notothenioid fish inhabit the Southern Ocean, the frigid sea that encircles Antarctica. Their ability to live in the icy seawater is so extraordinary that they make up more than 90 percent of the fish biomass of the region.

With NSF support, Arthur DeVries discovered antifreeze proteins in Antarctic notothenioid fish in the late 1960s, and was the first to describe how the proteins bind to ice crystals in the blood to prevent the fish from freezing.

The most recent antifreeze discovery was supported by a grant from NSF’s Division of Polar Programs.

The Division manages the United States Antarctic Program, through which it coordinates all U.S. research on the southernmost continent and provides the logistical framework to support the science.

This long-standing and continuously refined work on the antifreeze properties of Antarctic fish exemplifies one of the best and defining features of good science,” said Charles Amsler, organisms and ecosystems program director in Polar Programs.

“These researchers not only have for decades consistently produced new and exciting finds that contribute to our understanding of Antarctic ecosystems, but very often those new finds have led to new questions and deeper understandings across biology as a whole,” he added.

In the new study, the team investigated whether the antifreeze protein-bound ice crystals inside these fish would melt as expected when temperatures warmed.

When researchers warmed the fish to temperatures above the expected melting point, some internal ice crystals failed to melt. Ice that doesn’t melt at its normal melting point is referred to as “superheated.”

The researchers also found ice crystals in wild notothenioid fish swimming in relatively warmer Antarctic summer waters, at temperatures where they would be expected to be free of ice. By testing the antifreeze proteins in the lab, the team found that these proteins also were responsible for preventing the internal ice crystals from melting.

“Our discovery may be the first example of ice superheating in nature,” Cheng said.

A diver himself, Cziko worked with other divers to place and maintain a temperature-logging device in Antarctica’s McMurdo Sound, one of the coldest marine environments on the planet. The device recorded ocean temperatures there for 11 years, a substantial portion of notothenioids’ lifespan. Not once in that time did temperatures increase enough to overcome the antifreeze proteins’ anti-melting effect to completely rid the fish of their internal ice, the researchers report.

The researchers suspect that the accumulation of ice inside the fish could have adverse physiological consequences, but none have yet been discovered.

If the fish are destined to carry ice crystals around all their lives, Cheng said, it is conceivable that ice particles could obstruct small capillaries or trigger undesired inflammatory responses. Cziko likens the potential threat to dangers posed by asbestos in the lungs or blood clots in the brain.

“Since much of the ice accumulates in the fish spleens, we think there may be a mechanism to clear the ice from the circulation,” he said.

“This is just one more piece in the puzzle of how notothenioids came to dominate the ocean around Antarctica,” he said. “It also tells us something about evolution. That is, adaptation is a story of trade-offs and compromise. Every good evolutionary innovation probably comes with some bad, unintended effects.”

The long-term temperature record of McMurdo Sound produced in the study also “will prove to be of great importance and utility to the polar research community that is addressing organismal responses to climate change in this coldest of all marine environments,” Cheng said.

Clive W. Evans, a professor of molecular genetics and development at the University of Auckland in New Zealand, also is a co-author of the new paper.

High circular polarization (the red and white regions in the image) observed in the infrared light from reflection nebulae in the star-forming region Orion OMC1 (Bailey et al. 1998). It is caused by alignment of the dust particles in magnetic field, but can be responsible for formation of homochiral organics in these dust particles. Credit: Bailey et al. 1998 / University of New South Wales, available at: http://newt.phys.unsw.edu.au/~jbailey/chirality.html

Light Scattering on Dust Holds Clues to Habitability

High circular polarization (the red and white regions in the image) observed in the infrared light from reflection nebulae in the star-forming region Orion OMC1 (Bailey et al. 1998). It is caused by alignment of the dust particles in magnetic field, but can be responsible for formation of homochiral organics in these dust particles. Credit: Bailey et al. 1998 / University of New South Wales, available at: http://newt.phys.unsw.edu.au/~jbailey/chirality.html

High circular polarization (the red and white regions in the image) observed in the infrared light from reflection nebulae in the star-forming region Orion OMC1 (Bailey et al. 1998). It is caused by alignment of the dust particles in magnetic field, but can be responsible for formation of homochiral organics in these dust particles. Credit: Bailey et al. 1998 / University of New South Wales, available at: http://newt.phys.unsw.edu.au/~jbailey/chirality.html

We are all made of dust. Dust particles can be found everywhere in space. Disks of dust and debris swirl around and condense to form stars, planets and smaller objects like comets, asteroids and dwarf planets. But what can dust tell us about life’s potential in the Universe?

Astrobiologists study dust particles in space for many reasons. The behavior of particles in planet-forming disks yields clues about how planets form and evolve. Studying the composition of dust can help us understand the conditions that lead to habitability on those planets.

But how do you determine if dust contains molecules that may be important for the origin of life, or other materials that could be used to construct habitable environments?

Shining the Light

Astrobiologists study dust in space by watching light coming from dusty regions. As a light wave interacts with the tiny particles, the light is scattered. This scattering causes changes in the light wave. These can include an effect called circular polarization (CP).

A light wave can be roughly imagined as a single line that wiggles up and down. If circular polarization occurs, this line rotates as the wave moves. On paper, the effect looks a bit like a slinky or an old-fashioned spiral telephone chord.

“Discussions on what causes circular polarization (CP) observed in dusty objects can be seen quite often in scientific papers,” said Ludmilla Kolokolova, a senior research scientist at the University of Maryland’s Department of Astronomy. “Among the most popular explanations of the CP formation are scattering of light on aligned elongated/irregular dust particles, or on the particles that contain homochiral molecules.”

The electric field vectors of a traveling circularly polarized electromagnetic wave. Credit: Wikimedia Commons

The electric field vectors of a traveling circularly polarized electromagnetic wave. Credit: Wikimedia Commons

It’s the potential role of homochiral molecules that makes this process particularly interesting for astrobiology.

Chirality refers to molecules that are identical, but can exist in forms that are mirror-images of one another. It’s similar to a person’s left and right hands. They are both hands and are made up of the same five fingers, but the arrangement of the fingers defines each hand as either left or right. Homochirality means that even though both right- and left-hand forms of an object are possible, only one is found in the environment. This is often the case for some molecules used to build life on Earth.

Many molecules used in life — including sugars and amino acids — can theoretically exist in both left and right-handed forms. However, life on Earth has a preference for only one type. Amino acids, for example, are typically found in the left-handed form. The introduction of right-handed amino acids actually causes cells to die.

If light has passed through dust in space and experienced CP formation, it could tell astronomers whether or not that dust contains homochiral molecules, which could be an indictor of interest to astrobiologists.

Right-handed/clockwise circularly polarized light displayed with and without the use of components. This would be considered left-handed/counter-clockwise circularly polarized if defined from the point of view of the source rather than the receiver. Credit: Wikimedia Commons

Right-handed/clockwise circularly polarized light displayed with and without the use of components. This would be considered left-handed/counter-clockwise circularly polarized if defined from the point of view of the source rather than the receiver. Credit: Wikimedia Commons

Dust isn’t only present in planet and star-forming disks. Comets in the Solar System shed dust as they orbit the Sun, and dust in the atmospheres of extrasolar planets can also affect light by reflecting it. Studying how CP occurs in each of these cases, and whether or not homochiral molecules are involved, could aid in the study of these astrobiologically significant objects.

“If we learn how to separate CP caused by alignment from CP caused by homochirality, we get a good tool in the search for pre-biological and biological materials in space, especially in circumstellar disks and exoplanets,” Kolokolova told Astrobiology Magazine.

Raise Your Hand

Kolokolova and Lev Nagdimunov (an undergraduate when the study was made, and now a research assistant in Kolokolova’s group at the University of Maryland) used computer models to study the behavior of light waves in order to see if they could spot a difference in CP caused by alignment of the light wave on elongated dust particles, and CP caused by interactions with homochiral molecules.

Example of chirality of amino acids

Amino acids, sugars and other chiral molecules come in two varieties that are mirror images of each other. Credit: NASA

“One way to answer what causes CP in this or that case is to see which mechanism is more realistic for the given environment,” said Kolokolova. “For example, in star forming regions, alignment in magnetic fields looks more realistic. However, this is not so obvious for comets, and will be even more difficult to determine in the case of observing CP in exoplanets.”

At first glance, the two types of CP look very similar. Looking at the two light beams head on, they appear identical.

“Unfortunately a simple way to distinguish between these two mechanism based on the difference in the phase function of their CP cannot be used. ‘Phase function’ is dependent on phase angle, and phase angle is the angle between the star (Sun), dust particle, and observer (Earth),” explained Kolokolova. “The phase functions for aligned particles and homochiral molecules are quite similar and, within the errors of observations, almost indistinguishable.”

With computer modelling, the team found a slight difference in the exact backscatter and forward scatter directions of light that becomes circularly polarized by alignment versus homochirality. The team hopes that by watching how light is backscattered and forward scattered by dust, they can identify specific signatures for each of the two cases.

An excess of left-handed amino acids has been found in a few meteorites, including the Murchison meteorite, which landed in Australia in 1969. Credit: NASA

An excess of left-handed amino acids has been found in a few meteorites, including the Murchison meteorite, which landed in Australia in 1969.
Credit: NASA

“Using these results, we can plan observations directed to search for prebiological/biological materials in space, especially in disks and exoplanets,” said Kolokolova. “And they can be used in studies of the origin of homochirality; for example, through a survey of homochiral molecules in cosmic dust of different ages.”

Kolokolova also points out that identifying homochiral molecules in space can provide important clues about the origins of life. Evidence from meteorites supports the idea that the origin of left-handed himochirality in amino acids used by biology on Earth is related to conditions in the early Solar System. If the dust that formed our solar system only contained left-handed amino acids, it could explain why life on Earth developed a preference for these molecules in the first place. A survey of cosmic dust could reveal that homochirality is Universal, but that doesn’t mean that every system would be just like ours.

“It is likely that on other worlds, right-handed amino acids could dominate,” said Kolokolova. “It depends on the properties of the original magnetic field that aligned dust particles in star-forming regions.”

This work was supported by the Exobiology & Evolutionary Biology element of the NASA Astrobiology Program.

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NASA Telescopes Find Clear Skies and Water Vapor on Exoplanet

A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist's depiction. Such crossings, or transits, are observed by telescopes like NASA's Hubble and Spitzer to glean information about planets' atmospheres. Image Credit: NASA/JPL-Caltech

A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist’s depiction. Such crossings, or transits, are observed by telescopes like NASA’s Hubble and Spitzer to glean information about planets’ atmospheres. Image Credit: NASA/JPL-Caltech

Astronomers using data from three of NASA’s space telescopes — Hubble, Spitzer and Kepler — have discovered clear skies and steamy water vapor on a gaseous planet outside our solar system. The planet is about the size of Neptune, making it the smallest planet from which molecules of any kind have been detected.

“This discovery is a significant milepost on the road to eventually analyzing the atmospheric composition of smaller, rocky planets more like Earth,” said John Grunsfeld, assistant administrator of NASA’s Science Mission Directorate in Washington. “Such achievements are only possible today with the combined capabilities of these unique and powerful observatories.”

Clouds in a planet’s atmosphere can block the view to underlying molecules that reveal information about the planet’s composition and history. Finding clear skies on a Neptune-size planet is a good sign that smaller planets might have similarly good visibility.

“When astronomers go observing at night with telescopes, they say ‘clear skies’ to mean good luck,” said Jonathan Fraine of the University of Maryland, College Park, lead author of a new study appearing in Nature. “In this case, we found clear skies on a distant planet. That’s lucky for us because it means clouds didn’t block our view of water molecules.”

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes. Image Credit: NASA/JPL-Caltech

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA’s Hubble, Spitzer and Kepler space telescopes. Image Credit: NASA/JPL-Caltech

The planet, HAT-P-11b, is categorized as an exo-Neptune — a Neptune-sized planet that orbits the star HAT-P-11. It is located 120 light-years away in the constellation Cygnus. This planet orbits closer to its star than does our Neptune, making one lap roughly every five days. It is a warm world thought to have a rocky core and gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.

Part of the challenge in analyzing the atmospheres of planets like this is their size. Larger Jupiter-like planets are easier to see because of their impressive girth and relatively inflated atmospheres. In fact, researchers already have detected water vapor in the atmospheres of those planets. The handful of smaller planets observed previously had proved more difficult to probe partially because they all appeared to be cloudy.

In the new study, astronomers set out to look at the atmosphere of HAT-P-11b, not knowing if its weather would call for clouds. They used Hubble’s Wide Field Camera 3, and a technique called transmission spectroscopy, in which a planet is observed as it crosses in front of its parent star. Starlight filters through the rim of the planet’s atmosphere; if molecules like water vapor are present, they absorb some of the starlight, leaving distinct signatures in the light that reaches our telescopes.

Using this strategy, Hubble was able to detect water vapor in HAT-P-11b. But before the team could celebrate clear skies on the exo-Neptune, they had to show that starspots — cooler “freckles” on the face of stars — were not the real sources of water vapor. Cool starspots on the parent star can contain water vapor that might erroneously appear to be from the planet.

The NASA/ESA Hubble Space Telescope during Servicing Mission 4

The NASA/ESA Hubble Space Telescope during Servicing Mission 4

The team turned to Kepler and Spitzer. Kepler had been observing one patch of sky for years, and HAT-P-11b happens to lie in the field. Those visible-light data were combined with targeted Spitzer observations taken at infrared wavelengths. By comparing these observations, the astronomers figured out that the starspots were too hot to have any steam. It was at that point the team could celebrate detecting water vapor on a world unlike any in our solar system. This discovery indicates the planet did not have clouds blocking the view, a hopeful sign that more cloudless planets can be located and analyzed in the future.

“We think that exo-Neptunes may have diverse compositions, which reflect their formation histories,” said study co-author Heather Knutson of the California Institute of Technology in Pasadena. “Now with data like these, we can begin to piece together a narrative for the origin of these distant worlds.”

The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapor, hydrogen gas and likely other yet-to-be-identified molecules. Theorists will be drawing up new models to explain the planet’s makeup and origins.

“We are working our way down the line, from hot Jupiters to exo-Neptunes,” said Drake Deming, a co-author of the study also from University of Maryland. “We want to expand our knowledge to a diverse range of exoplanets.”

This image, taken with ground-based telescopes, shows the region of sky containing the star HAT-P-11. Credit: NASA, ESA, Digitized Sky Survey 2. Acknowledgement: Davide De Martin

This image, taken with ground-based telescopes, shows the region of sky containing the star HAT-P-11. Credit: NASA, ESA, Digitized Sky Survey 2. Acknowledgement: Davide De Martin

The astronomers plan to examine more exo-Neptunes in the future, and hope to apply the same method to super-Earths — massive, rocky cousins to our home world with up to 10 times the mass. Although our solar system doesn’t have a super-Earth, NASA’s Kepler mission is finding them in droves around other stars. NASA’s James Webb Space Telescope, scheduled to launch in 2018, will search super-Earths for signs of water vapor and other molecules; however, finding signs of oceans and potentially habitable worlds is likely a ways off.

“The work we are doing now is important for future studies of super-Earths and even smaller planets, because we want to be able to pick out in advance the planets with clear atmospheres that will let us detect molecules,” said Knutson.

Once again, astronomers will be crossing their fingers for clear skies.

Primary deployment test of the three-fold solar panel. Credit: ISRO

MOM Arrives at Mars

Primary deployment test of the three-fold solar panel. Credit: ISRO

Primary deployment test of the three-fold solar panel. Credit: ISRO

This week has been a busy time for robotic explorers at Mars. NASA’s MAVEN spacecraft successfully entered orbit on Sunday, September 21. Days later, a second new Mars mission has now reached the red planet.

India has become the fourth nation to successfully deliver a spacecraft to Mars. The Mars Orbiter Mission (MOM) is the country’s first interplanetary mission and is primarily focused on proving technological capabilities for the Indian Space Research Organization (ISRO).

On the science front, MOM will collect data about martian surface features, morphology and mineralogy. The spacecraft will also search for signs of methane gas in the atmosphere.

MOM’s payload includes:

Lyman Alpha Photometer (LAP): measures the ratio of deuterium and hydrogen in the upper atmosphere of Mars, helping scientists understand the loss of water from the planet.

Artist representation of the MOM spacecraft. Credit: ISRO

Artist representation of the MOM spacecraft. Credit: ISRO

Methane Sensor for Mars (MSM): measures methane in the martian atmosphere and maps its sources.

Mars Exospheric Neutral Composition Analyser (MENCA): a quadruple mass spectrometer that has its heritage in the Altitudinal Composition Explorer (CHACE) payload on a previous ISRO mission to the Moon, Chandrayaan.

Mars Color Camera (MCC): a tri-color camera that will provide data on the composition of the martian surface. MCC will also spend time capturing images of Mars’ moons Phobos and Deimos.

Thermal Infrared Imaging Spectrometer (TIS): will measure thermal emissions from Mars during both day and night, allowing scientists to map the surface composition and mineralogy of Mars.

MOM joins six active missions at Mars including the MAVEN orbiter, the Mars Reconnaissance Orbiter, Mars Express, Mars Odyssey, the Opportunity rover and the Curiosity rover. Together, this team of robotic explorers are providing valuable information about Mars’ present environment, and clues as to whether or not the planet supported habitats in its history where life could have survived.


 


A special documentary film on Mars Orbiter Mission. Credit: Ministry of Information & Broadcasting (YouTube)

Image Credit: NASA

If You Could Hitch a Ride to Mars…

Image Credit: NASA

Image Credit: NASA

With the successful orbital insertion of the MAVEN spacecraft, NASA has opened registration for the Mars Balance Mass Challenge and has launched a new website for citizen scientists called NASA Solve.

The Mars Balance Mass Challenge is a new initiative to engage the public in developing future Mars missions. Space missions are always an exercise in balancing mass. First you have the mass of the spacecraft and the fuel cost of launching that mass into space. Next you have the launch vehicle and the maximum amount of mass that it’s rockets can push into the sky and beyond. Then, when a spacecraft carrying a lander reaches Mars and enters the atmosphere, mass has to be ejected to balance the lander.

One trick for mission planners is to balance all these factors and maximize the amount of scientific instruments that can be carried within all the constraints on a missions’ mass.

NASA is turning to the public for design ideas that can “turn available entry, descent, and landing balance mass on a future Mars mission into a scientific or technological payload.”

Artist’s concept shows the entry, descent and landing sequence that a lander would undergo on its way to Mars. Image Credit: NASA/JPL

Artist’s concept shows the entry, descent and landing sequence that a lander would undergo on its way to Mars. Image Credit: NASA/JPL

The small payloads would provide a dual purpose by providing ejectable weight to balance planetary landers, and by collecting data that can help planetary scientists and astrobiologists learn about the red planet.

Submissions are due by Nov. 21, 2014. A winner will be announced in mid-January 2015 and receive an award of $20,000.

“We want people to get involved in our journey to Mars,” said Lisa May, lead program executive for NASA’s Mars exploration program in a recent press release. “This challenge is a creative way to bring innovative ideas into our planning process, and perhaps help NASA find another way to pack more science and technology into a mission.”

NASA Solve is a new website that will host all of NASA’s challenges and prizes. The site has a wealth of information on how citizen scientists can get involved in NASA missions, including details on the Mars Balance Challenge:

http://www.nasa.gov/solve/marsbalancechallenge

The Mars Balance Mass challenge is managed by NASA’s Center of Excellence for Collaborative Innovation (CoECI). CoECI was established in coordination with White House Office of Science and Technology Policy to advance NASA open innovation efforts and extend that expertise to other federal agencies. The challenges are being released on the NASA Innovation Pavilion, one of the CoECI platforms available to NASA team members, through its contract with InnoCentive, Inc.


 


Seven Minutes of Terror: The Challenges of Getting to Mars. Credit: NASA JPL (YouTube).
Curiosity performed one of NASA’s most memorable martian landings to date. In this video, team members at NASA’s Jet Propulsion Laboratory share the challenges of the Curiosity Mars rover’s final minutes to landing on the surface of Mars.

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Arctic sea ice helps remove CO2 from the atmosphere

Dorte Haubjerg Søgaard from University of Denmark/Grønlands Naturinstitut studies how sea ice removes CO2 from the atmosphere. Photo: Søren Rysgaard.

Dorte Haubjerg Søgaard from University of Denmark/Grønlands Naturinstitut studies how sea ice removes CO2 from the atmosphere. Photo: Søren Rysgaard.

Climate change is a fact, and most of the warming is caused by human activity. The Arctic is now so warm that the extent of sea ice has decreased by about 30 pct. in summer and in winter, sea ice is getting thinner. New research has shown that sea ice removes CO2 from the atmosphere. If Arctic sea ice is reduced, we may therefore be facing an increase of atmospheric concentration of CO2, researchers warn.

Due to global warming, larger and larger areas of sea ice melt in the summer and when sea ice  freezes over in the winter it is thinner and more reduced. As the Arctic summers are getting warmer we may see an acceleration of global warming, because reduced sea ice in the Arctic will remove less CO2 from the atmosphere, Danish scientists report.

“If our results are representative, then sea ice plays a greater role than expected, and we should take this into account in future global CO2 budgets”, says Dorte Haubjerg Søgaard, PhD Fellow, Nordic Center for Earth Evolution, University of Southern Denmark and the Greenland Institute of Natural Resources, Nuuk.

Sea ice draws CO2 from the atmosphere

Only recently scientists have realized that sea ice has an impact on the planet’s CO2 balance.

“We have long known that the Earth’s oceans are able to absorb huge amounts of CO2. But we also thought that this did not apply to ocean areas covered by ice, because the ice was considered impenetrable. However, this is not true: New research shows that sea ice in the Arctic draws large amounts of CO2 from the atmosphere into the ocean”, says Dorte Haubjerg Søgaard.

Dorte Haubjerg Søgaard has just completed her studies of sea ice in Greenland. The studies show that sea ice may have a major impact on the global carbon cycle, and that chemical processes have a much greater impact on the sea ice’s ability to remove CO2 than biological processes. The research is published as a series of articles in scientific journals.

A frost flower has emerged on new sea ice. Photo: David Barber.

A frost flower has emerged on new sea ice. Photo: David Barber.

“The chemical removal of CO2 in sea ice occurs in two phases. First crystals of calcium carbonate are formed in sea ice in winter. During this formation CO2 splits off and is dissolved in a heavy cold brine, which gets squeezed out of the ice and sinks into the deeper parts of the ocean. Calcium carbonate cannot move as freely as CO2 and therefore it stays in the sea ice. In summer, when the sea ice melts, calcium carbonate dissolves, and CO2 is needed for this process. Thus, CO2 gets drawn from the atmosphere into the ocean – and therefore CO2 gets removed from the atmosphere”, explains Dorte Haubjerg Søgaard.

The biological removal of CO2 is done by algae binding of carbon in organic material.

Frost flowers also contribute

Another important discovery is that every winter flower-like ice formations are formed on the surface of newly formed sea ice. They are called frost flowers. Dorte Haubjerg Søgaard has discovered that these frost flowers hold extremely high concentrations of calcium carbonate, which can have a further significant impact on the potential CO2 uptake in the Arctic.

Fruit flies such as these spent one month aboard the International Space Station during the Heart Flies study. Image Credit: NASA / Dominic Hart

Flying in Orbit

Fruit flies such as these spent one month aboard the International Space Station during the Heart Flies study. Image Credit: NASA / Dominic Hart

Fruit flies such as these spent one month aboard the International Space Station during the Heart Flies study. Image Credit: NASA / Dominic Hart

The astronaut badge may be limited to human beings, but we’re not the only organisms that have made it into orbit. From microorganisms to animals, many travelers have made the journey to the International Space Station. Among the most-traveled organisms are Drosophila melanogaster, more commonly  known as fruit flies.

The flies are studied by scientists who are interested in how life from Earth adapts to conditions in the space environment. Such studies have important implications for space biology and medicine. For astrobiologists, these studies can also provide important clues about the evolutionary mechanisms and adaptations that could have theoretically shaped life on other worlds (if life ever found a foothold beyond Earth).

Fruit flies are one of the classic test subjects for numerous biological and biomedical studies on Earth and in orbit. Because the basic biochemical machinery is the same for all life as we know it, fruit flies can act as an important model for medical studies that have applications in humans and other animals.

Any student of biology or genetics is familiar with the fruit fly and, in fact, a new fruit fly mission to the ISS has its origins in student education. NASA’s Ames student Fruit-Fly Experiment (AFEx) has helped train graduate and undergraduate students by providing opportunities to work hand-in-hand with NASA scientists on spaceflight experiments.

Groups of fruit flies studied in the Heart Flies investigation were housed in tubes with ventilated caps and pre-loaded with fly food. Image Credit: NASA / Dominic Hart

Groups of fruit flies studied in the Heart Flies investigation were housed in tubes with ventilated caps and pre-loaded with fly food. Image Credit: NASA / Dominic Hart

When the most recent cargo resupply servicing mission left Earth for the the ISS, it carried a payload of new fruit flies into orbit. They were launched to the station on SpaceX’s Dragon spacecraft. Data will be collected from the experiment for around a month, and then the flies will return to Earth on the same Dragon capsule.

Interestingly, NASA recently announced that SpaceX will provide future transportation for astronauts to and from the space station. Before those human explorers are carried into orbit aboard a Dragon, fruit flies will have already made the journey

For more information about AFEx and the current crew of fruit flies heading to the ISS, see this press release from the NASA Ames Research Center.

The SpaceX Falcon 9 carrying a Dragon spacecraft loaded with scientific equipment and cargo launches from Cape Canaveral Air Force Station, Florida, on Sept. 21, 2014. Image Credit: NASA/Frankie Martin

The SpaceX Falcon 9 carrying a Dragon spacecraft loaded with scientific equipment and cargo launches from Cape Canaveral Air Force Station, Florida, on Sept. 21, 2014. Image Credit: NASA/Frankie Martin

Educational Resources

Fruit flies have played a major role in science education throughout the years, and there are numerous resources online to learn more about these tiny space explorers. Here’s a few worth checking out:

Flies in Space!: Fruit flies feature on this educational page from NASAQuest.

Astrobiology Short Course: This online short course from Montana State University describes how experiments with fruit flies apply to astrobiology and our understanding of the fundamental mechanisms of life.

The Wonderful Fruit Fly (University of North Carolina): This site explains how fruit flies are used in genetics, and has resources for both teachers and students.

PBS Learning (Public Broadcasting): This educational production on ‘the Gene’ from Public Broadcasting stars the fruit fly.

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Is Pluto a Planet? The Votes Are In

Pluto (left) and Charon (right) dominate this view of the outer solar system. Charon is about half the size of Pluto. Pluto also hosts four tiny moons - Nix, Hydra, Kerberos, and Styx - two of which are seen as small crescents at top left and right. In the distance, a faint Sun illuminates dust within the asteroid belt. David A. Aguilar (CfA)

Pluto (left) and Charon (right) dominate this view of the outer solar system. Charon is about half the size of Pluto. Pluto also hosts four tiny moons – Nix, Hydra, Kerberos, and Styx – two of which are seen as small crescents at top left and right. In the distance, a faint Sun illuminates dust within the asteroid belt. David A. Aguilar (CfA)

What is a planet? For generations of kids the answer was easy. A big ball of rock or gas that orbited our Sun, and there were nine of them in our solar system. But then astronomers started finding more Pluto-sized objects orbiting beyond Neptune. Then they found Jupiter-sized objects circling distant stars, first by the handful and then by the hundreds. Suddenly the answer wasn’t so easy. Were all these newfound things planets?

Since the International Astronomical Union (IAU) is in charge of naming these newly discovered worlds, they tackled the question at their 2006 meeting. They tried to come up with a definition of a planet that everyone could agree on. But the astronomers couldn’t agree. In the end, they voted and picked a definition that they thought would work.

The current, official definition says that a planet is a celestial body that:

  1. is in orbit around the Sun,
  2. is round or nearly round, and
  3. has “cleared the neighborhood” around its orbit.

But this definition baffled the public and classrooms around the country. For one thing, it only applied to planets in our solar system. What about all those exoplanets orbiting other stars? Are they planets? And Pluto was booted from the planet club and called a dwarf planet. Is a dwarf planet a small planet? Not according to the IAU. Even though a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster.

Eight years later, the Harvard-Smithsonian Center for Astrophysics decided to revisit the question of “what is a planet?” On September 18th, we hosted a debate among three leading experts in planetary science, each of whom presented their case as to what a planet is or isn’t. The goal: to find a definition that the eager public audience could agree on!

Science historian Dr. Owen Gingerich, who chaired the IAU planet definition committee, presented the historical viewpoint. Dr. Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint. And Dr. Dimitar Sasselov, director of the Harvard Origins of Life Initiative, presented the exoplanet scientist’s viewpoint.

Gingerich argued that “a planet is a culturally defined word that changes over time,” and that Pluto is a planet. Williams defended the IAU definition, which declares that Pluto is not a planet. And Sasselov defined a planet as “the smallest spherical lump of matter that formed around stars or stellar remnants,” which means Pluto is a planet.

After these experts made their best case, the audience got to vote on what a planet is or isn’t and whether Pluto is in or out. The results are in, with no hanging chads in sight.

According to the audience, Sasselov’s definition won the day, and Pluto IS a planet.

On Sept. 18, 2014, audience members who attended the Observatory Night talk "What is a Planet?" voted to choose one of three possible definitions for a planet. The result: a planet is "the smallest spherical lump of matter than formed around stars or stellar remnants," and Pluto IS a planet! Harvard-Smithsonian CfA

On Sept. 18, 2014, audience members who attended the Observatory Night talk “What is a Planet?” voted to choose one of three possible definitions for a planet. The result: a planet is “the smallest spherical lump of matter than formed around stars or stellar remnants,” and Pluto IS a planet! Harvard-Smithsonian CfA

The video of the debate and audience vote can be seen here: