These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta. Credit: NASA / JPL-Caltech / Hap McSween (Univ. Tennessee), A. Beck and T. McCoy (Smithsonian Inst.)

The Abundance of Water in Asteroid Fragments

These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta. Credit: NASA / JPL-Caltech / Hap McSween (Univ. Tennessee), A. Beck and T. McCoy (Smithsonian Inst.)

These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta. Credit: NASA / JPL-Caltech / Hap McSween (Univ. Tennessee), A. Beck and T. McCoy (Smithsonian Inst.)

A new study could provide insights about the abundance of water in fragments from a famous asteroid.

The study focused on a mineral called apatite, which can act as a record of the volatiles in materials, including things like magma and lunar rocks. Volatiles are chemical elements with low boiling points (like water), and are usually associated with a celestial bodies’ crust or atmosphere.

By looking at the apatite in meteorites, the team was able to determine the history of water in these rocks from space.

The meteorites they chose to study are known as the Howardite-Eucrite-Diogenite (HED) meteorites. These meteorites are a subset of the achondrite meteorites, which are stony meteorites that do not have any chondrites (round grains that were formed from molten droplets of material floating around in space before being incorporated into an asteroid).

HED meteorites only account for only 2-3% of the meteorites that are collected on Earth.

Vesta closeup. Credit: NASA

Vesta closeup. Credit: NASA

Studying the composition of meteorites can provide important clues about how asteroids and other rocky bodies form and evolve. Volatile elements influence processes important to planet formation, such as melting and eruption processes.

HED meteorites are especially interesting because scientists think they originated from the crust of the asteroid Vesta – a large body in the main asteroid belt that was recently visited by NASA’s Dawn spacecraft. Behind Ceres, Vesta is the second largest object in the asteroid belt and is sometimes referred to as a protoplanet.

Vesta is a relic of the ancient Solar System and can help astrobiologists understand our system’s formation and evolution. This information provides clues about conditions in the Solar System that led to the formation of a habitable planet – the Earth.

Interestingly, the team’s results from the HED meteorites are similar to studies on the Earth and Moon, and could support theories that water in all three objects (Vesta, the Earth, and the Moon) came from the same source.

77th Annual Meteoritical Society Meeting (2014). Credit: http://www.metsoc2014casablanca.org/

77th Annual Meteoritical Society Meeting (2014). Credit: http://www.metsoc2014casablanca.org/

The results of the study were presented at the 77th Annual Meeting of the Meteoritical Society (MetSoc) in Casablanca, Morocco, which took place from September 8-13, 2014. The program with abstracts is available from http://www.metsoc2014casablanca.org/.

Untitled

Titan Glowing at Dusk and Dawn

High in the atmosphere of Titan, large patches of two trace gases glow near the north pole, on the dusk side of the moon, and near the south pole, on the dawn side. Brighter colors indicate stronger signals from the two gases, HNC (left) and HC3N (right); red hues indicate less pronounced signals. Image Credit: NRAO/AUI/NSF

High in the atmosphere of Titan, large patches of two trace gases glow near the north pole, on the dusk side of the moon, and near the south pole, on the dawn side. Brighter colors indicate stronger signals from the two gases, HNC (left) and HC3N (right); red hues indicate less pronounced signals. Image Credit: NRAO/AUI/NSF

New maps of Saturn’s moon Titan reveal large patches of trace gases shining brightly near the north and south poles. These regions are curiously shifted off the poles, to the east or west, so that dawn is breaking over the southern region while dusk is falling over the northern one.

The pair of patches was spotted by a NASA-led international team of researchers investigating the chemical make-up of Titan’s atmosphere.

“This is an unexpected and potentially groundbreaking discovery,” said Martin Cordiner, an astrochemist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of the study. “These kinds of east-to-west variations have never been seen before in Titan’s atmospheric gases. Explaining their origin presents us with a fascinating new problem.”

The mapping comes from observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), a network of high-precision antennas in Chile. At the wavelengths used by these antennas, the gas-rich areas in Titan’s atmosphere glowed brightly. And because of ALMA’s sensitivity, the researchers were able to obtain spatial maps of chemicals in Titan’s atmosphere from a “snapshot” observation that lasted less than three minutes.

Titan’s atmosphere has long been of interest because it acts as a chemical factory, using energy from the sun and Saturn’s magnetic field to produce a wide range of organic, or carbon-based, molecules. Studying this complex chemistry may provide insights into the properties of Earth’s very early atmosphere, which may have shared many chemical characteristics with present-day Titan.

A view of Titan's surface captured by the Cassini spacecraft, which probed through the hazy atmosphere with radar. Credit: NASA/JPL/Space Science Institute

A view of Titan’s surface captured by the Cassini spacecraft, which probed through the hazy atmosphere with radar. Credit: NASA/JPL/Space Science Institute

In this study, the researchers focused on two organic molecules, hydrogen isocyanide (HNC) and cyanoacetylene (HC3N), that are formed in Titan’s atmosphere. At lower altitudes, the HC3N appears concentrated above Titan’s north and south poles. These findings are consistent with observations made by NASA’s Cassini spacecraft, which has found a cloud cap and high concentrations of some gases over whichever pole is experiencing winter on Titan.

The surprise came when the researchers compared the gas concentrations at different levels in the atmosphere. At the highest altitudes, the gas pockets appeared to be shifted away from the poles. These off-pole locations are unexpected because the fast-moving winds in Titan’s middle atmosphere move in an east–west direction, forming zones similar to Jupiter’s bands, though much less pronounced. Within each zone, the atmospheric gases should, for the most part, be thoroughly mixed.

The researchers do not have an obvious explanation for these findings yet.

“It seems incredible that chemical mechanisms could be operating on rapid enough timescales to cause enhanced ‘pockets’ in the observed molecules,” said Conor Nixon, a planetary scientist at Goddard and a coauthor of the paper, published online today in the Astrophysical Journal Letters. “We would expect the molecules to be quickly mixed around the globe by Titan’s winds.”

At the moment, the scientists are considering a number of potential explanations, including thermal effects, previously unknown patterns of atmospheric circulation, or the influence of Saturn’s powerful magnetic field, which extends far enough to engulf Titan.

Further observations are expected to improve the understanding of the atmosphere and ongoing processes on Titan and other objects throughout the solar system.

It is possible to study the atmospheres of giant transiting planets as the light shines through the atmosphere.

What Does the Next Generation Telescope Need to Detect Life?

The mock spectra are shown for different values of resolution. For low values of resolution, it becomes harder to detect the elements. Water is easier to detect than oxygen, and the ozone signal is very weak. Credit: Brandt & Spiegel 2014. Reproduced with permission from Proceedings of the National Academy of Sciences USA

The mock spectra are shown for different values of resolution. For low values of resolution, it becomes harder to detect the elements. Water is easier to detect than oxygen, and the ozone signal is very weak.
Credit: Brandt & Spiegel 2014. Reproduced with permission from Proceedings of the National Academy of Sciences USA

Almost 2,000 extrasolar planets have been discovered to date and this number is constantly increasing. Yet, we still know little about these alien worlds, especially their atmospheres. The atmospheres of terrestrial exoplanets could betray the presence of life on the planet, sparking NASA’s interest in acquiring the spectra that appears as starlight shines through these planetary atmospheres.

A paper by Timothy Brandt and David Spiegel, exo-planetary scientists at the Institute for Advanced Study, Princeton, details what is needed in a next generation telescope for it to be capable of detecting signatures of life in the atmospheres of alien planets. The paper has been published in the September issue of the journal Proceedings of the National Academy of Sciences.

Signatures of a habitable planet

Astronomers employ several different methods to study the atmospheres of gas giants that orbit close to their host stars. One such method involves comparing the spectrum of a star when a planet is transiting across the surface to a spectrum when the planet is out of transit. By comparing the spectra, it is possible to see which elements exist in the planet’s atmosphere.

Methods like this still can’t be used for terrestrial planets, as the height of the atmosphere engulfing a rocky planet is miniscule compared to that of a gas giant. Earth-like planets also orbit their stars at a larger distance, making it even more difficult to observe their atmospheres.

Observations of terrestrial planet atmospheres will require a specialized space mission that will use a coronograph to block out the blinding light of the star. While the James Webb Space Telescope, due to launch in 2018, will be capable of detecting elements in planetary atmospheres, it will still be limited to more massive planets.

“Our paper is an attempt to better define the requirements for a mission capable of detecting oxygen and water,” says Brandt. “This is NASA’s target, assuming technology developments in coronagraphy and adaptive optics permit it.”

The detection of oxygen and water on another planet does not necessarily mean that life is present, but it certainly increases the chances that life might exist there. Oxygen on Earth is mainly produced by photosynthesis. However, the level of oxygen has varied dramatically over the lifetime of the Earth.

Also, it should be cautioned that oxygen can be produced abiotically. Water molecules can be broken apart in a process known as photolysis, and this can create abundant oxygen in a planetary atmosphere even when no life is present.

The paper by Brandt and Spiegel discusses the detection limits of chlorophyll. The chlorophyll in plants on Earth reflect more light in the infrared than they do in visible light, which causes a bump in the spectrum. This is known as the “red edge of chlorophyll,” and it can be seen in the Earth’s spectrum.

While the detection of chlorophyll would be exciting, there would also be some controversy surrounding such a detection. Using the “red edge” as a biosignature assumes that photosynthesis by plants on an alien world occurs in the exact same way as it does on Earth. In reality, such plants may use a molecule other than chlorophyll, or they may be optimized for light at a different wavelength.

Credit: ESA with adaptations by David Sing

It is possible to study the atmospheres of giant transiting planets as the light shines through the atmosphere.
Credit: ESA with adaptations by David Sing

“The main reason why a claimed detection would be so controversial is because it’s easy to imagine features of your instrument or detector that could change the shape of the spectrum,” adds Brandt. “The calibration of the instrument would have to be very, very good to trust a chlorophyll detection.”

Signal-to-noise and resolution

The researchers used model spectra to calculate the signal-to-noise ratio that would be needed in order to detect biomarkers on terrestrial planets. The signal-to-noise ratio is a number that specifies how much actual data exist compared to “noise.” Noise in this sense is not related to sound, rather it describes the “junk” signal that appears in the spectrum.

Noise can be caused by instrumental defects, or because the object under study is quite faint. Noise is inevitable in measurements of light; for example, a photograph taken in low light with a digital camera will appear grainy. A high signal-to-noise ratio indicates that the data is of high quality, and better results can be obtained. For example a signal-to-noise ratio of 10 means that the signal is 10 times stronger than the noise.

They also calculated the optimum spectral resolution needed to find the elusive signatures of life. Not to be confused with the angular resolution of a telescope, the resolution of a spectrograph is a number that details the ability of the spectrograph to differentiate between similar colors, or wavelengths, of light. For instance, if the resolution of the spectrograph is 100, it means that smallest difference in wavelength that can be resolved is one part in 100, or 1 percent. As with signal-to-noise, a higher number for spectral resolution is usually better, although this depends on the type of observations that are being performed.

Credit: John Walker's "Earth Viewer," Christine Lafon, (Harvard-Smithsonian Center for Astrophysics)

An artist’s depiction of the Earth enhanced to show the red edge of chlorophyll.
Credit: John Walker’s “Earth Viewer,” Christine Lafon, (Harvard-Smithsonian Center for Astrophysics)

Detecting biosignatures

Their results show that water is the easiest feature to detect in a terrestrial planet spectrum. It has several deep features that can still be seen even down to a low spectral resolution of 20, although the ideal minimum is 40 and a resolution of 200 would ensure much more detail of the water features. Assuming a resolution of 150, the signal-to-noise ratio only needs to be 3 in order to detect water.

Oxygen (O2) needs a resolution of at least 150 and a signal-to-noise ratio twice what is needed to detect water. As the ultraviolet light from stars creates ozone (O3), a logical step would also to be search for ozone, however this is not as easy as it sounds.

“The problem is that O3 is a broad, shallow feature, and is therefore very difficult to see,” explains Brandt. “As a result, you might as well just look for the deeper, narrower O2 features.”

For the red edge of chlorophyll, a low resolution of 20 will suffice, however the signal-to-noise needs to be six times higher than that needed to detect oxygen. This means a telescope would need to be trained on the planet for a very long time in order to gather enough light to have a high signal. The “red edge” would be easier to detect if the vegetation covered around 30 percent of the planet, or if the cloud cover was very low.

These results show that any future mission should be designed primarily with the detection of water and oxygen in mind. Given the difficulty in detecting chlorophyll, and the controversy surrounding such a detection, the authors suggest that chlorophyll should only be sought on the best targets.

One such future mission currently on the drawing board is the Advanced Technology Large-Aperture Space Telescope (ATLAST).

“It’s hard to say whether ATLAST would be able to detect O2 and H2O in general,” says Brandt. “It depends on many things, including the design of ATLAST (which is still very much a concept) and the distance of the planet from Earth.”

If the ATLAST mission is given the go ahead, it would take images and spectra in the optical, infrared, and ultraviolet. Its primary mission would be to determine biosignatures, and it is planned for the 2025 to 2035 period.

Untitled

Secrets of Dinosaur Ecology Found in Fragile Amber

Photos of inclusions in Canadian Cretaceous amber from Grassy Lake amber, a 78-79 million year old amber in the Late Cretaceous of southern Alberta. Credit:  University of Alberta Strickland Entomology Museum (UASM) specimen, R.C. McKellar

Photos of inclusions in Canadian Cretaceous amber from Grassy Lake amber, a 78-79 million year old amber in the Late Cretaceous of southern Alberta. Credit: University of Alberta Strickland Entomology Museum (UASM) specimen, R.C. McKellar

Ryan McKellar’s research sounds like it was plucked from Jurassic Park: he studies pieces of amber found buried with dinosaur skeletons. But rather than re-creating dinosaurs, McKellar uses the tiny pieces of fossilized tree resin to study the world in which the now-extinct behemoths lived.

New techniques for investigating very tiny pieces of fragile amber buried in dinosaur bonebeds could close the gaps in knowledge about the ecology of the dinosaurs, said McKellar, who is a research scientist at the Royal Saskatchewan Museum in Saskatchewan, Canada.

“Basically it puts a backdrop to these dinosaur digs, it tells us a bit about the habitat,” said McKellar.

The amber can show what kinds of plants were abundant, and what the atmosphere was like at the time the amber was formed, he explained. Scientists can then put together details regarding what kind of habitat the dinosaur lived in and how the bonebed formed.

Photo of amber and plant fossils from the ‘Scotty’ Tyrannosaurus rex quarry in Saskatchewan. Photo credit: Royal Saskatchewan Museum (RSM) for the Scotty amber photographs.

Photo of amber and plant fossils from the ‘Scotty’ Tyrannosaurus rex quarry in Saskatchewan. Photo credit: Royal Saskatchewan Museum (RSM) for the Scotty amber photographs.

The preliminary findings about dinosaur ecology, habitat, and other results from four different fossil deposits from the Late Cretaceous in Alberta and Saskatchewan, Canada, were presented on Monday, October 20 at the Geological Society of America Annual Meeting in Vancouver, Canada.

“Just a few of these little pieces among the bones can show a lot of information,” McKellar said.

The type of amber that the scientists work with is not like the jewelry grade variety that can be made into a necklace or earrings. “This type of amber hasn’t been pursued in the past. It is like working with a shattered candy cane,” he said. It is called friable amber, which is crumbly and fragile.

McKellar and his colleagues work with very small pieces of amber, just millimeters wide. But even samples at such a small scale can hold enormous clues to the past.

Before it hardened into amber, the sticky tree resin would often collect animal and plant material, like leaves and feathers. Scientists call these contents “inclusions,” which they study along with the surrounding amber, to look at environmental conditions, surrounding water sources, temperature, and even oxygen levels in the ancient environment.

Credit:  University of Alberta Strickland Entomology Museum (UASM) specimen, R.C. McKellar

Credit: University of Alberta Strickland Entomology Museum (UASM) specimen, R.C. McKellar

Insects can also be included in the amber, which can be even more helpful to scientists. One example is the discovery of an aphid, stuck directly to a duck-billed dinosaur with some amber. With a find like this, scientists can track insect evolution, find their modern relatives, and see how they might have interacted with dinosaurs, said McKellar.

“When you get insects, it is like frosting on the cake—you can really round out the view of the ecosystem.”

Improvements in processing friable amber have made this research possible. Instead of the past technique of screening amber in a glycerin bath, the scientists reduce crumbling by vacuum-injecting the amber with epoxy, said McKellar.

Friable amber is widespread across the North American Continent in association with coals, and in the uncovered bonebeds, which means this area of research has expanded with the new techniques. It means scientists can sample at a finer scale, and still close some gaps in the past, especially regarding insect evolution, said McKellar.

Untitled

Heavy Metal Frost? A New Look at a Venusian Mystery

Venus. Credit: Magellan Project, JPL, NASA

Venus. Credit: Magellan Project, JPL, NASA

Venus is hiding something beneath its brilliant shroud of clouds: a first order mystery about the planet that researchers may be a little closer to solving because of a new re-analysis of twenty-year-old spacecraft data.

Venus’s surface can’t be seen from orbit in visible light because of the planet’s hot, dense, cloudy atmosphere. Instead, radar has been used by spacecraft to penetrate the clouds and map out the surface – both by reflecting radar off the surface to measure elevation and by looking at the radio emissions of the hot surface. The last spacecraft to map Venus in this way was Magellan, two decades ago. One of the Venusian surprises discovered at that time is that radio waves are reflected differently at different elevations on Venus. Also observed were a handful of radio dark spots at the highest elevations. Both enigmas have defied explanation.

“There is general brightening upward trend in the highlands and then dark spots at the highest locations,” explained Elise Harrington, an Earth sciences undergraduate at Simon Fraser University, in British Columbia, who revisited the Venus data during her internship at the Lunar and Planetary Institute, under the direction of Allan Treiman.

Brightening, in this case, means the radio waves reflect well. Dark means the radio waves are not reflected. In other words, the higher you go on Venus, the more radio reflective the ground gets until it abruptly goes radio black.

“Like on Earth, the temperature changes with elevation,” Harrington explained. And the cooler temperatures at altitude lead to ice and snow, which create a similar pattern of brightening for Earth – but in visible light. “Among the possibilities on Venus are a temperature dependent chemical weathering process or heavy metal compound precipitating from the air – a heavy metal frost.”

This is a radar image of one of the areas sampled on Ovda. There is a smooth ramp across the map going from higher to lower elevations, shown as a gradual transition in radar brightness up the ramp. (The top of the ramp is brighter than the bottom of the ramp in the lower right corner). The bright areas to either side of the ramp are highland plateaus, and the curious dark spots are the mysterious areas at the highest elevations that the researchers are investigating.

This is a radar image of one of the areas sampled on Ovda. There is a smooth ramp across the map going from higher to lower elevations, shown as a gradual transition in radar brightness up the ramp. (The top of the ramp is brighter than the bottom of the ramp in the lower right corner). The bright areas to either side of the ramp are highland plateaus, and the curious dark spots are the mysterious areas at the highest elevations that the researchers are investigating.

Getting to the bottom of these mysteries has been very hard because Venus has not been revisited since Magellan and no better data is available.

So Harrington and Trieman made do by re-purposing the old data. They used recently-available stereo radar elevation data (from Dr. R. Herrick, University of Alaska) rather than using the lower resolution radar altimetry. That increased their altimetry resolution from seeing patches 8 by 12 kilometers to just 600×600 meters. They also used Magellan’s Synthetic Aperture Radar (SAR), with its 75×75-meter footprint, to look at radio reflectance, rather than the data on radio emissions from the surface, which had a coarser 15 by 23 kilometer resolution.

They applied these to two areas in the Odva Regio highlands region of Venus where they confirmed the same pattern of radar reflections brightening with increasing elevation, as was found by previous researchers. The radar reflection was low at the lower 2,400 meter (7,900 foot) elevation, then rapidly brightens up to 4,500 meters (14,700 feet). But they also found a lot more of those strange black spots, with a precipitous drop in the reflections at 4,700 meters (15,400 feet).

“The previous author saw a few dark spots,” said Harrington. “But we see hundreds of them.”

Years ago it was proposed that some sort of ferro-electric compound might be the cause of the brightening and the dark spots, but so far no specific compound has been identified which does the trick. Then again, with the surface of Venus being at almost 900 °F (500 °C) under more than 90 times the air pressure of Earth’s atmosphere at sea level, with occasional showers of acid, it’s not easy to test the properties of materials under Venusian conditions.

“No one knows what explains the sudden darkness,” said Harrington. “We think this might spur some more interest in Venus.”

Expose facility. Credit: ESA

Lichen in Orbit

The Expose-R2 experment on the outside of the Zvezda module of the International Space Station (ISS). Credit: DLR

The Expose-R2 experment on the outside of the Zvezda module of the International Space Station (ISS). Credit: DLR

A new study shows that a large percentage of hardy lichens exposed to space conditions for one and a half years remain viable after returning to Earth. The lichen Xanthoria elegans was part of the lichen and fungi experiment (LIFE) on the International Space Station (ISS).

The lichen had been exposed before on previous experiments such as BIOPAN, but never for such a long period of time.

Expose facility. Credit: ESA

Expose facility. Credit: ESA

LIFE was attached to the exterior of the ISS for 1.5 years, exposing the organisms inside to the stresses of low Earth orbit, including ultraviolet irradiation, cosmic radiation and vacuum conditions. A subset of the lichen samples were also exposed to simulated Mars conditions by adding an analog Mars atmosphere and solar radiation filters to the experimental chambers.

After their journey in space and return to the Earth surface, an impressive 71% of the lichen remained viable.

The study can help astrobiologists understand the mechanisms that living organisms might use to survive on planets other than Earth. These mechanisms provide clues about how life may have originated and evolved in the conditions present on locations like ancient Mars.

The research can also provide insight into a process known as lithopanspermia – the transfer of life from one celestial body to another inside rocks. For more information on this aspect of the LIFE experiment, see the video below from European Space Agency (ESA).


Small black rock-fungi and lichens on the way of Lithopanspermia. Credit: ESA (YouTube)

Untitled

Scientists create possible precursor to life

Model of a protocell. Image by Janet Iwasa

Model of a protocell. Image by Janet Iwasa

How did life originate? And can scientists create life? These questions not only occupy the minds of scientists interested in the origin of life, but also researchers working with technology of the future. If we can create artificial living systems, we may not only understand the origin of life – we can also revolutionize the future of technology.

Protocells are the simplest, most primitive living systems, you can think of. The oldest ancestor of life on Earth was a protocell, and when we see, what it eventually managed to evolve into, we understand why science is so fascinated with protocells. If science can create an artificial protocell, we get a very basic ingredient for creating more advanced artificial life.

However, creating an artificial protocell is far from simple, and so far no one has managed to do that. One of the challenges is to create the information strings that can be inherited by cell offspring, including protocells. Such information strings are like modern DNA or RNA strings, and they are needed to control cell metabolism and provide the cell with instructions about how to divide.

Essential for life

If one daughter cell after a division has a slightly altered information (maybe it provides a slightly faster metabolism), they may be more fit to survive. Therefor it may be selected and an evolution has started.

Now researchers from the Center for Fundamental Living Technology (FLINT), Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, describe in the journal Europhysics Letters, how they, in a virtual computer experiment, have discovered information strings with peculiar properties.

Professor and head of FLINT, Steen Rasmussen, says: “Finding mechanisms to create information strings are essential for researchers working with artificial life.”

An autocatalytic network is a network of molecules, which catalyze each other’s production. Each molecule can be formed by at least one chemical reaction in the network, and each reaction can be catalyzed by at least one other molecule in the network. This process will create a network that exhibits a primitive form of metabolism and an information system that replicates itself from generation to generation. Credit University of Southern Denmark.

An autocatalytic network is a network of molecules, which catalyze each other’s production. Each molecule can be formed by at least one chemical reaction in the network, and each reaction can be catalyzed by at least one other molecule in the network. This process will create a network that exhibits a primitive form of metabolism and an information system that replicates itself from generation to generation. Credit University of Southern Denmark.

Steen Rasmussen and his colleagues know they face two problems:

Firstly long molecular strings are decomposed in water. This means that long information strings “break” quickly in water and turn into many short strings. Thus it is very difficult to maintain a population of long strings over time.

Secondly, it is difficult to make these molecules replicate without the use of modern enzymes, whereas it is easier to make a so-called ligation.  A ligation is to connect any combination of two shorter strings into a longer string, assisted by another matching longer string. Ligation is the mechanism used by the SDU-researchers.

“In our computer simulation – our virtual molecular laboratory – information strings began to replicate quickly and efficiently as expected. However, we were struck to see that the system quickly developed an equal number of short and long information strings and further that a strong pattern selection on the strings had occurred. We could see that only very specific information patterns on the strings were to be seen in the surviving strings. We were puzzled: How could such a coordinated selection of strings occur, when we knew that we had not programmed it. The explanation had to be found in the way the strings interacted with each other”, explains Steen Rasmussen.

It is like society

According to Steen Rasmussen, a so-called self-organizing autocatalytic network was created in the virtual pot, into which he and his colleagues poured the ingredients for information strings.

An autocatalytic network is a network of molecules, which catalyze each other’s production. Each molecule can be formed by at least one chemical reaction in the network, and each reaction can be catalyzed by at least one other molecule in the network. This process will create a network that exhibits a primitive form of metabolism and an information system that replicates itself from generation to generation.

“An autocatalytic network works like a community; each molecule is a citizen who interacts with other citizens and together they help create a society”, explains Steen Rasmussen.

This autocatalytic set quickly evolved into a state where strings of all lengths existed in equal concentrations, which is not what is usually found. Further, the selected strings had strikingly similar patterns, which is also unusual.

“We might have discovered a process similar to the processes that initially sparked the first life. We of course don’t know if life actually was created this way – but it could have been one of the steps. Perhaps a similar process created sufficiently high concentrations of longer information strings when the first protocell was created”, explains Steen Rasmussen.

Basis for new technology

The mechanisms underlying the formation and selection of effective information strings are not only interesting for the researchers who are working to create protocells. They also have value to researchers working with tomorrow’s technology, like they do at the FLINT Center.

“We seek ways to develop technology that’s based on living and life-like processes. If we succeed, we will have a world where technological devices can repair themselves, develop new properties and be re-used. For example a computer made of biological materials poses very different – and less environmentally stressful – requirements for production and disposal”, says Steen Rasmussen.

Ref: http://epljournal.edpsciences.org/articles/epl/abs/2014/14/epl16388/epl16388.html

Three-quarters of Earth’s surface is ocean. Designing procedures to detect the water from afar could help scientists do the same thing for exoplanets. Credit: NASA

Pesquisa Mostra Oceanos Como Vitais Para a Possibilidade de Vida Alienígena

This press release was originally published in English on July 22, 2014. This translation for the Portuguese edition of Astrobiology Magazine was provided by Bruno Martini. The original article is available here.

Artist’s conception of Kepler-69c, a rocky planet larger than Earth that orbits in what could be a habitable region of its star. Credit: NASA

Artist’s conception of Kepler-69c, a rocky planet larger than Earth that orbits in what could be a habitable region of its star. Credit: NASA

Nova pesquisa publicada no jornal Astrobiology mostra o papel vital dos oceanos na moderação do clima em planetas semelhantes à Terra.

Até agora, simulações por computador de climas habitáveis em planetas semelhantes à Terra focaram em suas atmosferas. Mas a presença de oceanos é vital para a estabilidade climática ótima e sua habitabilidade.

A equipe de pesquisa das faculdades de Matemática e Ciências Ambientais da UEA criou um padrão simulado por computador de circulação oceânica em um hipotético planeta semelhante à Terra coberto por oceanos. Eles observaram como diferentes taxas de rotação planetárias impactariam o transporte de calor com a presença dos oceanos sendo considerada.

O Prof. David Stevens da faculdade de Matemática da UEA disse: ´´O número de planetas sendo descobertos fora do Sistema Solar está crescendo rapidamente. Esta pesquisa ajudará a responder se estes planetas poderiam sustentar vida alienígena.

´´Sabemos que muitos planetas são completamente inabitáveis porque eles estão muito próximos ou muito distantes das suas estrelas. Uma zona habitável é baseada na distância do planeta de sua estrela e em temperaturas em que é possível para o planeta possuir manter a água líquida.

´´Mas até agora, a maioria dos modelos de habitabilidade negligenciaram o impacto dos oceanos no clima´´.

´´Os oceanos possuem uma imensa capacidade de controlar o clima. Eles são benéficos porque eles fazem a temperatura de superfície responder a mudanças sazonais muito lentas no aquecimento solar. E eles ajudam a assegurar que as variações de temperatura através de um planeta sejam mantidas a níveis toleráveis´´.

´´Nós descobrimos que o calor transportado pelos oceanos teria um grande impacto na distribuição da temperatura pelo planeta e potencialmente permitiria que uma maior área do planeta fosse habitável´´.

´´Marte, por exemplo, está na zona habitável do Sol, mas não possui oceanos – fazendo as temperaturas do ar variarem acima de 100oC. Os oceanos ajudam a fazer o clima de um planeta mais estável, então considerá-los em modelos climáticos é vital para saber se um planeta pode desenvolver e sustentar vida´´.

´´Este novo modelo nos ajudará a entender como os climas de outros planetas podem ser com detalhes mais acurados que nunca´´.

The Importance of Planetary Rotation Period for Ocean Heat Transport (A Importância do Período de Rotação Planetário para o Transporte de Calor no Oceano) foi publicada no jornal Astrobiology na segunda-feira, 21 de julho de 2014. A pesquisa foi financiada pelo – Engineering and Physical Sciences Research Council EPSRC (Conselho de Pesquisa em Engenharia e Ciências Físicas).

Tradutor: Bruno Martini


A publicação de comunicados de imprensa e outros conteúdos terceirizados não significam apoio ou filiação de qualquer tipo.

Untitled

All Three NASA Mars Orbiters Healthy After Comet Flyby

This artist's concept shows NASA's Mars orbiters lining up behind the Red Planet for their "duck and cover" maneuver to shield them from comet dust from the close flyby of comet Siding Spring (C/2013 A1) on Oct. 19, 2014. NASA/JPL-Caltech

This artist’s concept shows NASA’s Mars orbiters lining up behind the Red Planet for their “duck and cover” maneuver to shield them from comet dust from the close flyby of comet Siding Spring (C/2013 A1) on Oct. 19, 2014. NASA/JPL-Caltech

All three NASA orbiters around Mars confirmed their healthy status Sunday after each took shelter behind Mars during a period of risk from dust released by a passing comet.

Mars Odyssey, Mars Reconnaissance Orbiter and the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter all are part of a campaign to study comet C/2013 A1 Siding Spring and possible effects on the Martian atmosphere from gases and dust released by the comet. The comet sped past Mars today much closer than any other know comet flyby of a planet.

Additional information about the precautions and observations by each of the three orbiters is at:

› Mars Odyssey mission status report

The longest-lived robot ever sent to Mars came through its latest challenge in good health, reporting home on schedule after sheltering behind Mars from possible comet dust.

Artist's concept of NASA's Mars Odyssey spacecraft. Image credit: NASA/JPL-Caltech

Artist’s concept of NASA’s Mars Odyssey spacecraft. Image credit: NASA/JPL-Caltech

› Mars Reconnaissance Orbiter mission status report

NASA’s Mars Reconnaissance Orbiter, which has sent home more data about Mars than all other missions combined, is also now providing data about a comet that buzzed The Red Planet today (Oct. 19).

Artist's concept of the Mars Reconnaissance Orbiter spacecraft. Image credit: NASA/JPL-Caltech

Artist’s concept of the Mars Reconnaissance Orbiter spacecraft. Image credit: NASA/JPL-Caltech

› MAVEN mission status report

NASA’s newest orbiter at Mars, MAVEN, took precautions to avoid harm from a dust-spewing comet that flew near Mars and is studying the flyby’s effects on the Red Planet’s atmosphere.

Artist's concept of the MAVEN Mars orbiter spacecraft. Image credit: NASA/JPL-Caltech

Artist’s concept of the MAVEN Mars orbiter spacecraft. Image credit: NASA/JPL-Caltech

For more information about comet Siding Spring and the investigations of its Mars flyby, visit:

http://mars.jpl.nasa.gov/comets/sidingspring/

Thousands of exoplanets and exoplanet candidates have been discovered, but astronomers are still searching for exomoons. Credit: ESA - C. Carreau

Exomoons Could Be Abundant Sources Of Habitability

Europa is one of the moons in our solar system that could host life. What about beyond the solar system? Credit: NASA/JPL/Ted Stryk

Europa is one of the moons in our solar system that could host life. What about beyond the solar system? Credit: NASA/JPL/Ted Stryk

With about 4,000 planet candidates from the Kepler Space Telescope data to analyze so far, astronomers are busy trying to figure out questions about habitability. What size planet could host life? How far from its star does it need to be? What would its atmosphere need to be made of?

Look at our own solar system, however, and there’s a big gap in the information we need. Most of the planets have moons, so surely at least some of the Kepler finds would have them as well. Tracking down these tiny worlds, however, is a challenge.

A new paper in the journal Astrobiology, called “Formation, Habitability, and Detection of Extrasolar Moons,” goes over this mostly unexplored field of extrasolar research. The scientists do an extensive literature review of what is supposed about moons beyond the Solar System, and they add intriguing new results.

A wealth of moons exist in our own solar system that could host life. Icy Europa, which is circling Jupiter, was recently discovered to have plumes of water erupting from its surface. Titan, in orbit around Saturn, is the only known moon with an atmosphere, and could have the precursor elements to life in its hydrocarbon seas that are warmed by Saturn’s heat. Other candidates for extraterrestrial hosts include Jupiter’s moons Callisto and Ganymede, as well as Saturn’s satellite Enceladus.

Lead author René Heller, an astrophysicist at the Origins Institute at McMaster University, in Ontario, Canada, said some exomoons could be even better candidates for life than many exoplanets.

“Moons have separate energy sources,” he said. “While the habitability of terrestrial planets is mostly determined by stellar illumination, moons also receive reflected stellar light from the planet as well as thermal emission from the planet itself.”

Moreover, a planet like Jupiter — which hosts most of the moons in the Solar System that could support life — provides even more potential energy sources, he added. The planet is still shrinking and thereby converts gravitational energy into heat, so that it actually emits more light than it receives from the Sun, providing yet more illumination. Besides that, moons orbiting close to a gas giant are flexed by the planet’s gravity, providing potential tidal heating as an internal, geological heat source.

Triton's odd, melted appearance hint that the moon was captured and altered by Neptune. Credit: NASA

Triton’s odd, melted appearance hint that the moon was captured and altered by Neptune. Credit: NASA

Finding the first exomoon

The first challenge in studying exomoons outside our Solar System is to actually find one. Earlier this year, NASA-funded researchers reported the possible discovery of such a moon, but this claim was ambiguous and can never be confirmed. That’s because it appeared as a one-time event, when one star passed in front of another, acting as a sort of gravitational lens that amplified the background star. Two objects popped out in the gravitational lens in the foreground — either a planet and a star, or a planet and an extremely heavy exomoon.

For his part, Heller is convinced that exomoons are lurking in the Kepler data, but they have not been discovered yet. Only one project right now is dedicated to searching for exomoons, and is led by David Kipping at the Canadian Space Agency. His group has published several papers investigating 20 Kepler planets and candidates in total. The big restriction to their efforts is computational power, as their simulations require supercomputers.

Another limiting factor is the number of observatories that can search for exomoons. To detect them, at least a handful of transits of the planet-moon system across their common host star would be required to absolutely make sure that the companion is a moon, Heller said. Also, the planet with the moon would have to be fairly far from its star, and decidedly not those close-in hot Jupiters that take only a few days to make an orbit. In that zone, the gravitational drag of the star would fatally perturb any moon’s orbit.

Heller estimates that a telescope would need to stare constantly at the same patch of sky for several hundred days, minimum, to pick up an exomoon. Kepler fulfilled that obligation in spades with its four years of data gazing at the same spot in the sky, but astronomers will have to wait again for that opportunity.

Because two of Kepler’s gyroscopes (pointing devices) have failed, Kepler’s new mission will use the pressure of the Sun to keep it steady. But it can only now point to the same region of the sky for about 80 days at at time because the telescope will periodically need to be moved so as not to risk placing its optics too close to the Sun.

NASA’s forthcoming Transiting Exoplanet Survey Satellite is only expected to look at a given field for 70 days. Further into the future, the European Space Agency’s PLAnetary Transits and Oscillations of stars (PLATO) will launch in 2024 for what is a planned six-year mission looking at several spots in the sky.

PLATO is the next step, with a comparable accuracy to Kepler but a much larger field of view and hopefully a longer field of view coverage,” Heller said.

Clues in our solar system

Thousands of exoplanets and exoplanet candidates have been discovered, but astronomers are still searching for exomoons. Credit: ESA - C. Carreau

Thousands of exoplanets and exoplanet candidates have been discovered, but astronomers are still searching for exomoons. Credit: ESA – C. Carreau

Heller characterizes moons as an under-appreciated feature of extrasolar planetary systems. Just by looking around us in the Solar System, he says, astronomers have been able to make crucial explanations about how the moons must have formed and evolved together with their planets. Moons thus carry information about the substructure of planet evolution, which is not accessible by planet observations alone.

The Earth’s moon, for example, was likely formed when a Mars-sized object collided with the proto-Earth and produced a debris disk. Over time, that debris coalesced into our moon.

While Heller says the literature mostly focuses on collision scenarios between an Earth-sized object and a Mars-sized object, he doesn’t see any reason why crashes on a bigger scale might not happen. Perhaps an Earth-sized object crashed into an object that was five times the mass of Earth, producing an extrasolar Earth-Earth binary planet system, he suggests.

Another collision scenario likely took place at Uranus. The gas giant’s rotation is tilted about 90 degrees in its orbit around the Sun. In other words, it is rolling on its side. More intriguing, its two dozen moons follow Uranus’ rotational equator, and they do not orbit in the same plane as Uranus’ track around the Sun. This scenario suggests that Uranus was hit multiple times by huge objects instead of just once, Heller said.

Examining mighty Jupiter’s moons gives astronomers a sense of how high temperatures were in the disk that formed the gas giant and its satellites, Heller added. Ganymede, for example, is an icy moon. Models indicate that beyond Ganymede’s orbit (at about 15 Jupiter radii) it is sufficiently cold for water to pass from the gas to the solid (ice) stage, so the regular moons in these regions are very water-rich compared to the inner, mostly rocky moons Io and Europa.

“It sounds a bit technical, but we couldn’t have this information about planetary accretion if we did not have the moons today to observe,” Heller said.

Some moons could also have been captured, such as Neptune’s large moon, Triton. The moon orbits in a direction opposite to other moons in Neptune‘s system (and in fact, opposite to the direction of other large moons in the Solar System.) Plus, its odd terrain suggests that it used to be a free-floating object that was captured by Neptune’s gravity. Neptune is so huge that it raised tides within the moon, reforming its surface.

There could be exomoons lurking in data already gathered by NASA's Kepler Space Telescope. Credit: NASA/Ames/JPL-Caltech

There could be exomoons lurking in data already gathered by NASA’s Kepler Space Telescope. Credit: NASA/Ames/JPL-Caltech

Even comparing the different types of moons around planets in the Solar System reveals different timescales of formation. Jupiter includes four moons similar in size to Earth’s moon (Europa, Callisto, Ganymede and Io), while the next largest planet in our solar system, Saturn, only has one large moon called Titan. Astronomers believe Saturn has only one large moon because the gas that formed objects in our solar system was more plentiful in Jupiter’s system to provide material for the moons to form.

The gas abundance happened as a consequence of the huge gas giant creating a void in the material surrounding our young Sun, pulling the material in for its moons. Saturn was not quite large enough to do this, resulting in fewer large moons.

More strange situations could exist beyond our solar system’s boundaries, but it will take a dedicated search to find exomoons. Once they are discovered, however, they will allow planet formation and evolution studies on a completely new level.

This research was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Center for Exoplanets and Habitable Worlds, which is supported by the Pennsylvania State University, the Pennsylvania Space Grant Consortium, the National Science Foundation (NSF) the NASA Astrobiology Institute.

Artist’s conception of Kepler-69c, a rocky planet larger than Earth that orbits in what could be a habitable region of its star. Credit: NASA

Rediscovering Venus to Find Faraway Earths

New optical device designed to measure gravitational pull of a planet should speed the search for Earth-like exoplanets

A habitable zone planet, Kepler-69c, in an artist's impression. The world is probably an inhospitable "super-Venus," but then again, it might be habitable, depending on the character of its atmosphere. Credit: NASA Ames/JPL-Caltech

Artists impression of Kepler-69c, a “super-Venus” that might be habitable depending on the character of its atmosphere. Credit: NASA Ames/JPL-Caltech

Astronomers Chih-Hao Li and David Phillips of the Harvard-Smithsonian Center for Astrophysics want to rediscover Venus—that familiar, nearby planet stargazers can see with the naked eye much of the year.

Granted, humans first discovered Venus in ancient times. But Li and Phillips have something distinctly modern in mind. They plan to find the second planet again using a powerful new optical device installed on the Italian National Telescope that will measure Venus’ precise gravitational pull on the sun. If they succeed, their first-of-its-kind demonstration of this new technology will be used for finding Earth-like exoplanets orbiting distant stars.

“We are building a telescope that will let us see the sun the way we would see other stars,” said Phillips, who is a staff scientist at the Harvard-Smithsonian Center for Astrophysics. He and Li, a research associate at the Center for Astrophysics, will describe the device in a paper to be presented at The Optical Society’s (OSA) 98th Annual Meeting, Frontiers in Optics, being held Oct. 19-23 in Tucson, Arizona, USA. Li is the lead author of the paper, which has 12 collaborators.

Astronomers have identified more than 1,700 exoplanets, some as far as hundreds of light years away. Most were discovered by the traditional transit method, which measures the decrease in brightness when a planet orbiting a distant star transits that luminous body, moving directly between the Earth and the star. This provides information about the planet’s size, but not its mass.

Li and Phillips are developing a new laser-based technology known as the green astro-comb for use with the “radial velocity method,” which offers complementary information about the mass of the distant planet.

From this information, astronomers will be able to determine whether distant exoplanets they discover are rocky worlds like Earth or less dense gas giants like Jupiter. The method is precise enough to help astronomers identify Earth-like planets in the “habitable zone,” the orbital distance “sweet-spot” where water exists as a liquid.

Better Precision with a Laser

The radial velocity method works by measuring how exoplanet gravity changes the light emitted from its star. As exoplanets circle a star, their gravitation tugs at the star changing the speed with which it moves toward or away from Earth by a small amount. The star speeds up slightly as it approaches Earth, with each light wave taking a fraction of a second less time to arrive than the wave before it.

To an observer on Earth, the crests of these waves look closer together than they should, so they appear to have a higher frequency and look bluer. As the star recedes, the crests move further apart and the frequencies seem lower and redder.

The astro-comb calibrates the Italian National Telescope's HARPS-Nspectrograph using an observation of the asteroid Vesta. The top figure is a colorizedversion of the raw HARPS-N spectrum, showing the astro-comb calibration dottedlines and the sun's spectrum reflected off Vesta as mostly solid vertical lines.The middle figure shows the raw data converted to a very precise standard one-dimensionalplot of spectral intensity vs. wavelength. The very regular astro-comb calibrationspectrum is below below. Credit: David Phillips

The astro-comb calibrates the Italian National Telescope’s HARPS-Nspectrograph using an observation of the asteroid Vesta. The top figure is a colorizedversion of the raw HARPS-N spectrum, showing the astro-comb calibration dottedlines and the sun’s spectrum reflected off Vesta as mostly solid vertical lines.The middle figure shows the raw data converted to a very precise standard one-dimensionalplot of spectral intensity vs. wavelength. The very regular astro-comb calibrationspectrum is below below. Credit: David Phillips

This motion-based frequency change is known as the Doppler shift. Astronomers measure it by capturing the spectrum of a star on the pixels of a digital camera and watching how it changes over time.

Today’s best spectrographs are only capable of measuring Doppler shifts caused by velocity changes of 1 meter per second or more. Only large gas giants or “super-earths” close to their host stars have enough gravity to cause those changes.

The new astro-comb Li, Phillips and their colleagues are developing, however, will be able to detect Doppler shifts as small as 10 centimeters per second—small enough to find habitable zone Earth-like planets, even from hundreds of light years away.

“The astro-comb works by injecting 8,000 lines of laser light into the spectrograph. They hit the same pixels as starlight of the same wavelength. This creates a comb-like set of lines that lets us map the spectrograph down to 1/10,000 of a pixel. So if I have light on this section of the pixel, I can tell you the precise wavelength,” Phillips explained.

“By calibrating the spectrograph this way, we can take into account very small changes in temperature or humidity that affect the performance of the spectrograph. This way, we can compare data we take tonight with data from the same star five years from now and find those very small Doppler shifts,” he said.

Seeing Green

Li and his co-researchers pioneered the astro-comb several years ago, but it only worked with infrared and blue light. Their new version of the astro-comb lets astronomers measure green light—which is better for finding exoplanets.

“The stars we look at are brightest in the green visible range, and this is the range spectrographs are built to handle,” Phillips said.

Building the green astro-comb was a challenge, since the researchers needed to convert red laser light to green frequencies. They did it by making small fibers that convert one color of light to another.

A slowly rotating planet is not guaranteed to be habitable, as is evident when looking at the inhospitable Venus. Credit: NASA/JPL/Caltech

Venus. Credit: NASA/JPL/Caltech

“Red light goes in and green light comes out,” Phillips said. “Even though I see it every day and understand the physics, it looks like magic.”

The researchers plan to test the green astro-comb by pointing it at our sun, analyzing its spectrum to see if they can find Venus and rediscover its characteristic period of revolution, its size, its mass and its composition.

“We know a lot about Venus, and we can compare our answers to what we already know, so we are more confident about our answers when we point our spectrographs at distant stars,” Li said.

The Harvard-Smithsonian team is installing this device on the High-Accuracy Radial Velocity Planet Searcher-North (HARPS-N), a new spectrograph designed to search for exoplanets using the Italian National Telescope.

“We will look at the thousands of potential exoplanets identified by the Kepler satellite telescope by the transit method. Together, our two methods can tell us a lot about those worlds,” Li said.

And, because he will have already discovered Venus, he will be more certain of the answers.

This composite of C/2013 A1 (Siding Spring) merges Swift UVOT images taken between May 27 and 29, 2014. Sunlight reflected from the comet's dust, which produces most of the light in this image, appears yellow; violet shows ultraviolet light produced by hydroxyl (OH), a molecular fragment of water. Image Credit: NASA/Swift/D. Bodewits (UMD), DSS

MAVEN’s View of Siding Spring at Mars

This composite of C/2013 A1 (Siding Spring) merges Swift UVOT images taken between May 27 and 29, 2014. Sunlight reflected from the comet's dust, which produces most of the light in this image, appears yellow; violet shows ultraviolet light produced by hydroxyl (OH), a molecular fragment of water. Image Credit: NASA/Swift/D. Bodewits (UMD), DSS

This composite of C/2013 A1 (Siding Spring) merges Swift UVOT images taken between May 27 and 29, 2014. Sunlight reflected from the comet’s dust, which produces most of the light in this image, appears yellow; violet shows ultraviolet light produced by hydroxyl (OH), a molecular fragment of water. Image Credit: NASA/Swift/D. Bodewits (UMD), DSS

 

Today is the day. On Oct 19, 2014, the comet Siding Spring is set to pass within 88,000 miles of Mars. For a comparison, the distance between the Moon and the Earth is 238,900 miles.

 


Observing Comet Siding Spring at Mars. Credit: MAVEN (YouTube)
 

NASA will be watching the comet with the entire fleet of active orbiters and rovers now at Mars. MAVEN (Mars Atmosphere and Volatile EvolutioN Mission) will be studying how gas and dust from the comet interact with the upper atmosphere of Mars.

NASA is taking steps to protect its Mars orbiters, while preserving opportunities to gather valuable scientific data. The NASA orbiters at Mars are Mars Reconnaissance Orbiter, Mars Odyssey and MAVEN. Image Credit: NASA/JPL-Caltech

This artist’s concept shows the NASA Mars orbiters lining up behind Mars for their “duck and cover” maneuver to shield them from comet dust that may result from the close flyby of Comet Siding Spring (C/2013 A1) on Oct. 19, 2014. NASA is taking steps to protect its Mars orbiters, while preserving opportunities to gather valuable scientific data. The NASA orbiters at Mars are Mars Reconnaissance Orbiter, Mars Odyssey and MAVEN. Image Credit: NASA/JPL-Caltech

However, NASA will also need to position orbiting spacecraft in a safe spot for the cometary encounter – ensuring that materials shed from the comet do not strike any sensitive mission equipment.

Diagram showing the position of the Oort Cloud. Credit: Southwest Research Institute

Diagram showing the position of the Oort Cloud. Credit: Southwest Research Institute

The material released by Siding Spring will be traveling at around 35 miles per second, relative to the spacecraft. At that speed, even tiny flecks of material can cause a lot of damage.

Siding Spring is an object that originates from a region of the outer solar system known as the Oort cloud.

Studying Siding Spring will help astrobiologists understand the nature of objects in this distant and mysterious region of the Solar System. Some theories suggest that these objects could have delivered water and other materials to the early Earth that were essential for the origins of life on our planet.

For more information from NASA (and some cool interactive content), visit: http://mars.nasa.gov/comets/sidingspring/

Image by Reto Stöckli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA GSFC

Earth’s magnetic field could flip within a human lifetime

Untitled

Image by Reto Stöckli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA GSFC

Imagine the world waking up one morning to discover that all compasses pointed south instead of north.

It’s not as bizarre as it sounds. Earth’s magnetic field has flipped – though not overnight – many times throughout the planet’s history. Its dipole magnetic field, like that of a bar magnet, remains about the same intensity for thousands to millions of years, but for incompletely known reasons it occasionally weakens and, presumably over a few thousand years, reverses direction.

Now, a new study by a team of scientists from Italy, France, Columbia University and the University of California, Berkeley, demonstrates that the last magnetic reversal 786,000 years ago actually happened very quickly, in less than 100 years – roughly a human lifetime.

“It’s amazing how rapidly we see that reversal,” said UC Berkeley graduate student Courtney Sprain. “The paleomagnetic data are very well done. This is one of the best records we have so far of what happens during a reversal and how quickly these reversals can happen.”

Sprain and Paul Renne, director of the Berkeley Geochronology Center and a UC Berkeley professor-in- residence of earth and planetary science, are coauthors of the study, which will be published in the November issue of Geophysical Journal International and is now available online.

Flip could affect electrical grid, cancer rates

The discovery comes as new evidence indicates that the intensity of Earth’s magnetic field is decreasing 10 times faster than normal, leading some geophysicists to predict a reversal within a few thousand years.

Left to right, Biaggio Giaccio, Gianluca Sotilli, Courtney Sprain and Sebastien Nomade sitting next to an outcrop in the Sulmona basin of the Apennine Mountains that contains the Matuyama-Brunhes magnetic reversal. A layer of volcanic ash interbedded with the lake sediments can be seen above their heads. Sotilli and Sprain are pointing to the sediment layer in which the magnetic reversal occurred. (Photo by Paul Renne)

Left to right, Biaggio Giaccio, Gianluca Sotilli, Courtney Sprain and Sebastien Nomade sitting next to an outcrop in the Sulmona basin of the Apennine Mountains that contains the Matuyama-Brunhes magnetic reversal. A layer of volcanic ash interbedded with the lake sediments can be seen above their heads. Sotilli and Sprain are pointing to the sediment layer in which the magnetic reversal occurred. (Photo by Paul Renne)

Though a magnetic reversal is a major planet-wide event driven by convection in Earth’s iron core, there are no documented catastrophes associated with past reversals, despite much searching in the geologic and biologic record. Today, however, such a reversal could potentially wreak havoc with our electrical grid, generating currents that might take it down.

And since Earth’s magnetic field protects life from energetic particles from the sun and cosmic rays, both of which can cause genetic mutations, a weakening or temporary loss of the field before a permanent reversal could increase cancer rates. The danger to life would be even greater if flips were preceded by long periods of unstable magnetic behavior.

“We should be thinking more about what the biologic effects would be,” Renne said.

Dating ash deposits from windward volcanoes

The new finding is based on measurements of the magnetic field alignment in layers of ancient lake sediments now exposed in the Sulmona basin of the Apennine Mountains east of Rome, Italy. The lake sediments are interbedded with ash layers erupted from the Roman volcanic province, a large area of volcanoes upwind of the former lake that includes periodically erupting volcanoes near Sabatini, Vesuvius and the Alban Hills.

Italian researchers led by Leonardo Sagnotti of Rome’s National Institute of Geophysics and Volcanology measured the magnetic field directions frozen into the sediments as they accumulated at the bottom of the ancient lake.

Sprain and Renne used argon-argon dating, a method widely used to determine the ages of rocks, whether they’re thousands or billions of years old, to determine the age of ash layers above and below the sediment layer recording the last reversal. These dates were confirmed by their colleague and former UC Berkeley postdoctoral fellow Sebastien Nomade of the Laboratory of Environmental and Climate Sciences in Gif-Sur-Yvette, France.

The ‘north pole’ — that is, the direction of magnetic north — was reversed a million years ago. This map shows how, starting about 789,000 years ago, the north pole wandered around Antarctica for several thousand years before flipping 786,000 years ago to the orientation we know today, with the pole somewhere in the Arctic.

The ‘north pole’ — that is, the direction of magnetic north — was reversed a million years ago. This map shows how, starting about 789,000 years ago, the north pole wandered around Antarctica for several thousand years before flipping 786,000 years ago to the orientation we know today, with the pole somewhere in the Arctic.

Because the lake sediments were deposited at a high and steady rate over a 10,000-year period, the team was able to interpolate the date of the layer showing the magnetic reversal, called the Matuyama-Brunhes transition, at approximately 786,000 years ago. This date is far more precise than that from previous studies, which placed the reversal between 770,000 and 795,000 years ago.

“What’s incredible is that you go from reverse polarity to a field that is normal with essentially nothing in between, which means it had to have happened very quickly, probably in less than 100 years,” said Renne. “We don’t know whether the next reversal will occur as suddenly as this one did, but we also don’t know that it won’t.”

Unstable magnetic field preceded 180-degree flip
Whether or not the new finding spells trouble for modern civilization, it likely will help researchers understand how and why Earth’s magnetic field episodically reverses polarity, Renne said.

The magnetic record the Italian-led team obtained shows that the sudden 180-degree flip of the field was preceded by a period of instability that spanned more than 6,000 years. The instability included two intervals of low magnetic field strength that lasted about 2,000 years each. Rapid changes in field orientations may have occurred within the first interval of low strength. The full magnetic polarity reversal – that is, the final and very rapid flip to what the field is today – happened toward the end of the most recent interval of low field strength.

Renne is continuing his collaboration with the Italian-French team to correlate the lake record with past climate change.

Untitled

Scientists discover carbonate rocks are unrecognized methane sink

Methane bubbles pour out between rocks at the seep site. The white material at lower right is a type of bacterial colony commonly observed at methane seeps. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Methane bubbles pour out between rocks at the seep site. The white material at lower right is a type of bacterial colony commonly observed at methane seeps. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Since the first undersea methane seep was discovered 30 years ago, scientists have meticulously analyzed and measured how microbes in the seafloor sediments consume the greenhouse gas methane as part of understanding how the Earth works.

The sediment-based microbes form an important methane “sink,” preventing much of the chemical from reaching the atmosphere and contributing to greenhouse gas accumulation. As a byproduct of this process, the microbes create a type of rock known as authigenic carbonate, which while interesting to scientists was not thought to be involved in the processing of methane.

That is no longer the case. A team of scientists has discovered that these authigenic carbonate rocks also contain vast amounts of active microbes that take up methane. The results of their study, which was funded by the National Science Foundation, were reported today in the journal Nature Communications.

“No one had really examined these rocks as living habitats before,” noted Andrew Thurber, an Oregon State University marine ecologist and co-author on the paper. “It was just assumed that they were inactive. In previous studies, we had seen remnants of microbes in the rocks – DNA and lipids – but we thought they were relics of past activity. We didn’t know they were active.

“This goes to show how the global methane process is still rather poorly understood,” Thurber added.

A vast mussel community found on flat bottom as well as on rocks rising a meter or more off the seafloor. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

A vast mussel community found on flat bottom as well as on rocks rising a meter or more off the seafloor. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Lead author Jeffrey Marlow of the California Institute of Technology and his colleagues studied samples from authigenic compounds off the coasts of the Pacific Northwest (Hydrate Ridge), northern California (Eel River Basin) and central America (the Costa Rica margin). The rocks range in size and distribution from small pebbles to carbonate “pavement” stretching dozens of square miles.

“Methane-derived carbonates represent a large volume within many seep systems and finding active methane-consuming archaea and bacteria in the interior of these carbonate rocks extends the known habitat for methane-consuming microorganisms beyond the relatively thin layer of sediment that may overlay a carbonate mound,” said Marlow, a geobiology graduate student in the lab of Victoria Orphan of Caltech.

These assemblages are also found in the Gulf of Mexico as well as off Chile, New Zealand, Africa, Europe – “and pretty much every ocean basin in the world,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

The study is important, scientists say, because the rock-based microbes potentially may consume a huge amount of methane. The microbes were less active than those found in the sediment, but were more abundant – and the areas they inhabit are extensive, making their importance potential enormous. Studies have found that approximately 3-6 percent of the methane in the atmosphere is from marine sources – and this number is so low due to microbes in the ocean sediments consuming some 60-90 percent of the methane that would otherwise escape.

Methane gas bubbles rise from the seafloor – this type of activity, originally noticed by the Okeanos Explorer in 2012 on a multibeam sonar survey, is what led scientists to the area. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Methane gas bubbles rise from the seafloor – this type of activity, originally noticed by the Okeanos Explorer in 2012 on a multibeam sonar survey, is what led scientists to the area. Image courtesy of Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Now those ratios will have to be re-examined to determine how much of the methane sink can be attributed to microbes in rocks versus those in sediments. The distinction is important, the researchers say, because it is an unrecognized sink for a potentially very important greenhouse gas.

“We found that these carbonate rocks located in areas of active methane seeps are themselves more active,” Thurber said. “Rocks located in comparatively inactive regions had little microbial activity. However, they can quickly activate when methane becomes available.

“In some ways, these rocks are like armies waiting in the wings to be called upon when needed to absorb methane.”

The ocean contains vast amounts of methane, which has long been a concern to scientists. Marine reservoirs of methane are estimated to total more than 455 gigatons and may be as much as 10,000 gigatons carbon in methane. A gigaton is approximate 1.1 billion tons.

By contrast, all of the planet’s gas and oil deposits are thought to total about 200-300 gigatons of carbon.

Untitled

Scientists find ancient mountains that fed early life

This image shows the ancient mountain site, Brazil. Credit: Carlos Ganade de Araujo

This image shows the ancient mountain site, Brazil. Credit: Carlos Ganade de Araujo

Scientists have found evidence for a huge mountain range that sustained an explosion of life on Earth 600 million years ago.

The mountain range was similar in scale to the Himalayas and spanned at least 2,500 kilometres of modern west Africa and northeast Brazil, which at that time were part of the supercontinent Gondwana.

“Just like the Himalayas, this range was eroded intensely because it was so huge. As the sediments washed into the oceans they provided the perfect nutrients for life to flourish,” said Professor Daniela Rubatto of the Research School of Earth Sciences at The Australian National University (ANU).

“Scientists have speculated that such a large mountain range must have been feeding the oceans because of the way life thrived and ocean chemistry changed at this time, and finally we have found it.”

Professors Rubatto and Hermann are shown at ANU Research School of Earth Sciences. Credit: Stuart Hay

Professors Rubatto and Hermann are shown at ANU Research School of Earth Sciences. Credit: Stuart Hay

The discovery is earliest evidence of Himalayan-scale mountains on Earth.

“Although the mountains have long since washed away, rocks from their roots told the story of the ancient mountain range’s grandeur,” said co-researcher Professor Joerg Hermann.

“The range was formed by two continents colliding. During this collision, rocks from the crust were pushed around 100 kilometres deep into the mantle, where the high temperatures and pressures formed new minerals.”

As the mountains eroded, the roots came back up to the surface, to be collected in Togo, Mali and northeast Brazil, by Brazilian co-researcher Carlos Ganade de Araujo, from the University of Sao Paolo.

Dr Ganade de Araujo recognised the samples were unique and brought the rocks to ANU where, using world-leading equipment, the research team accurately identified that the rocks were of similar age, and had been formed at similar, great depths.

The research team involved specialists from a range of different areas of Earth Science sharing their knowledge, said Professor Rubatto.

“With everyone cooperating to study tiny crystals, we have managed to discover a huge mountain range,” she said.