OpenX

Unseen Is Free

Unseen Is Free
Try It Now

Google Translate

Sunday, August 2, 2015

Key Building Blocks of Life Found on Comet Surface

Complex molecules that could be key building blocks of life, the daily rise and fall of temperature, and an assessment of the surface properties and internal structure of the comet are just some of the highlights of the first scientific analysis of the data returned by Rosetta’s lander Philae last November. 

  Credit: ESA

Early results from Philae’s first suite of scientific observations of Comet 67P/Churyumov­-Gerasimenko were published in a special edition of the journal Science.

CIVA camera 4 view

Credit: ESA

Data were obtained during the lander’s seven-hour descent to its first touchdown at the Agilkia landing site, which then triggered the start of a sequence of predefined experiments. But shortly after touchdown, it became apparent that Philae had rebounded and so a number of measurements were carried out as the lander took flight for an additional two hours some 100 m above the comet, before finally landing at Abydos.

Some 80% of the first science sequence was completed in the 64 hours following separation before Philae fell into hibernation, with the unexpected bonus that data were ultimately collected at more than one location, allowing comparisons between the touchdown sites.


Inflight science

After the first touchdown at Agilkia, the gas-sniffing instruments Ptolemy and COSAC analysed samples entering the lander and determined the chemical composition of the comet’s gas and dust, important tracers of the raw materials present in the early Solar System.

COSAC analysed samples entering tubes at the bottom of the lander kicked up during the first touchdown, dominated by the volatile ingredients of ice-poor dust grains. This revealed a suite of 16 organic compounds comprising numerous carbon and nitrogen-rich compounds, including four compounds – methyl isocyanate, acetone, propionaldehyde and acetamide – that have never before been detected in comets.

Meanwhile, Ptolemy sampled ambient gas entering tubes at the top of the lander and detected the main components of coma gases – water vapour, carbon monoxide and carbon dioxide, along with smaller amounts of carbon-bearing organic compounds, including formaldehyde.

Importantly, some of these compounds detected by Ptolemy and COSAC play a key role in the prebiotic synthesis of amino acids, sugars and nucleobases: the ingredients for life. For example, formaldehyde is implicated in the formation of ribose, which ultimately features in molecules like DNA.

The existence of such complex molecules in a comet, a relic of the early Solar System, imply that chemical processes at work during that time could have played a key role in fostering the formation of prebiotic material.


Comparing touchdown sites

Thanks to the images taken by ROLIS on the descent to Agilkia, and the CIVA images taken at Abydos, a visual comparison of the topography at these two locations could be made.

ROLIS images taken shortly before the first touchdown revealed a surface comprising metre-size blocks of diverse shapes, coarse regolith with grain sizes of 10–50 cm, and granules less than 10 cm across.

3D view of large boulder at Agilkia

Credit: ESA

The regolith at Agilkia is thought to extend to a depth of 2 m in places, but seems to be free from fine-grained dust deposits at the resolution of the images.

The largest boulder in the ROLIS field-of-view measures about 5 m high, with a peculiar bumpy structure and fracture lines running through it that suggest erosional forces are working to fragment the comet’s boulders into smaller pieces.

The boulder also has a tapered ‘tail’ of debris behind it, similar to others seen in images taken by Rosetta from orbit, yielding clues as to how particles lifted up from one part of the eroding comet are deposited elsewhere.

Brightness variations of comet surface

Credit: ESA

Over a kilometre away at Abydos, not only did the images taken by CIVA’s seven microcameras reveal details in the surrounding terrain down to the millimetre scale, but also helped decipher Philae’s orientation.

The lander is angled up against a cliff face that is roughly 1 m from the open ‘balcony’ side of Philae, with stereo imagery showing further topography up to 7 m away, and one camera with open sky above.

The images reveal fractures in the comet’s cliff walls that are ubiquitous at all scales. Importantly, the material surrounding Philae is dominated by dark agglomerates, perhaps comprising organic-rich grains. Brighter spots likely represent differences in mineral composition, and may even point to ice-rich materials.

From the surface to the interior
The MUPUS suite of instruments provided insight into the physical properties of Abydos. Its penetrating ‘hammer’ showed the surface and subsurface material sampled to be substantially harder than that at Agilkia, as inferred from the mechanical analysis of the first landing.

The results point to a thin layer of dust less than 3 cm thick overlying a much harder compacted mixture of dust and ice at Abydos. At Agilkia, this harder layer may well exist at a greater depth than that encountered by Philae.

MUPUS investigations at Abydos

Credit: ESA

The MUPUS thermal sensor, on Philae’s balcony, revealed a variation in the local temperature between about –180ºC and –145ºC in sync with the comet’s 12.4 hour day. The thermal inertia implied by the measured rapid rise and fall in the temperature also indicates a thin layer of dust atop a compacted dust-ice crust.

Moving below the surface, unique information concerning the global interior structure of the comet was provided by CONSERT, which passed radio waves through the nucleus between the lander and the orbiter.

Philae best fit search ellipse

Credit: ESA

The results show that the small lobe of the comet is consistent with a very loosely compacted (porosity 75–85%) mixture of dust and ice (dust-to-ice ratio 0.4–2.6 by volume) that is fairly homogeneous on the scale of tens of metres.

In addition, CONSERT was used to help triangulate Philae’s location on the surface, with the best fit solution currently pointing to a 21 x 34 m area.

“Taken together, these first pioneering measurements performed on the surface of a comet are profoundly changing our view of these worlds and continuing to shape our impression of the history of the Solar System,” says Jean-Pierre Bibring, a lead lander scientist and principal investigator of the CIVA instrument at the IAS in Orsay, France.

“The reactivation would allow us to complete the characterisation of the elemental, isotopic and molecular composition of the cometary material, in particular of its refractory phases, by APXS, CIVA-M, Ptolemy and COSAC.”

“With Philae making contact again in mid-June, we still hope that it can be reactivated to continue this exciting adventure, with the chance for more scientific measurements and new images which could show us surface changes or shifts in Philae’s position since landing over eight months ago,” says DLR’s Lander Manager Stephan Ulamec.

“These ground-truth observations at a couple of locations anchor the extensive remote measurements performed by Rosetta covering the whole comet from above over the last year,” says Nicolas Altobelli, ESA’s acting Rosetta project scientist.

“With perihelion fast approaching, we are busy monitoring the comet’s activity from a safe distance and looking for any changes in the surface features, and we hope that Philae will be able to send us complementary reports from its location on the surface.”


Contacts and sources:
ESA

Europe Working To Prevent Bioterrorist Attack

Specialist laboratories capable of detecting biological weapons are coming together to try to work on a master plan so that Europe is ready in the case of a bioterrorist attack.

Bioterrorism is the intentional release of harmful biological agents such as bacteria, viruses, or toxins. To protect citizens and national infrastructure, the race is on to improve Europe’s preparedness.

Biological toxins, viruses and bacteria pose a very real threat to our safety. 
Biological toxins, viruses and bacteria pose a very real threat to our safety. Image credit: PLANTFOODSEC
Image credit: PLANTFOODSEC

‘We are at a critical moment,’ said Dr Brigitte Dorner, coordinator of the EQuATox research project, which is working to network Europe’s toxin laboratories together. ‘In light of the attempted release of biological toxins in the past we have to make sure that we are well prepared.’

Technology to test for harmful agents is already being used, but laboratories currently use different testing methods, making any comparison of accuracy and sensitivity nearly impossible.

EQuATox, funded by the EU, has been tasked with developing research and best practices by establishing a network of laboratories among EU and associated countries. The project has so far linked 35 expert laboratories from 20 countries.

‘With the information obtained in large international proficiency tests, we now have for the first time a clear picture of where we stand in terms of biotoxin detection; this serves as starting point for further development and improvement,’ said Dr Dorner.

Response

If a bioterrorism attack was to occur, two information exchange systems are already in place within Europe. The Early Warning and Response System and the Rapid Alert System help connect the European Commission and national public health authorities in order to implement quick measures to control an outbreak.

While these systems support management actions, such as containment and distribution of medicine, dedicated laboratory networks are necessary because they prevent potential biothreats by linking experts specialised in detection and identification.

In terms of biological toxins, EQuATox has identified several expert laboratories which are well prepared for a potential incident and, in the case of an outbreak, would be able to support other countries.

‘This is a clear benefit of the project because incidents of biological toxins being intentionally released have occurred, like the ricin letters sent to Barack Obama in 2013,’ said Dr Dorner.

Ricin is a poison produced by the Ricinus communis plant to protect itself from insect pests. It is one of the most powerful plant toxins known today. Due to its toxicity, the poison has a history of military, criminal and terroristic use.

Common ground

There are several tests to detect ricin, including analysing samples of suspicious materials and tests on human body fluids. But now, EQuATox’s approach to detecting ricin, along with other biological toxins, is helping establish a European common ground in bioterrorism prevention.

Along with bioterrorism, the potential for terrorist attacks against agriculture, also known as agroterrorism, is increasingly recognised as a threat to international security.

‘Those affected will not be just the farmers and input providers, but also shippers, merchants, food retailers and the restaurant trade. It could also affect the tourism and transport sector,’ said Dr Paola Colla of the University of Turin, Italy, who is project manager at PLANTFOODSEC, a research project identifying agroterroism threats.

The PLANTFOODSEC project found that current EU capabilities to detect and respond to agroterrorism, or biocriminal acts, are very modest and divided among too many unrelated organisations.

In response, the project is establishing a virtual plant and food biosecurity centre to enhance international preparedness against agroterrorism. It focuses on biological threats that have the capacity to affect and damage agriculture, infect plants, and ultimately affect food and feed at any stage in the supply chain.

‘We have 600 pathogens which we analysed in terms of their economic effect on specific crops and potential threat level,’ said Dr Colla.

Ricin seeds produce a deadly poison which has been used in military and terror attacks.

Image credit: EQuATox

PLANTFOODSEC also has 13 partners located in eight different countries including the United States, Turkey, and Israel. The project has a unit working on hazard analysis, doing trials on certain pests and pathogens to determine how to tackle outbreaks. There is also a unit that visits farms to provide direct advice to farmers and to collect soil and plant samples as new diseases can arrive every year.

‘Agroterrorism is seen as a genuine threat by intelligence services because it’s an effective means for a terrorists to generate fear,’ said Dr Colla. ‘If something happens in Europe, then we need to be prepared in order to avoid something like the E. coli outbreak in Germany.’

The 2011 German E. coli outbreak highlighted the urgent need for rapid and reliable analytical methods. At the beginning, the source of the pathogen was thought to have come from Spanish cucumbers, but it was in fact from fenugreek seeds imported from Egypt and used in salads in the EU.

The extended process resulted in entire cucumber crops being destroyed and demand plummeting across Europe, which in turn caused farmers to suffer. The total economic losses were estimated between EUR 0.5 billion and EUR 3.2 billion.

Incidents such as these provide timely scientific inputs to enable a response to potential agroterrorism threats. This research can then be used to develop preventive crisis management to different intentional or unintentional outbreaks.

‘We publish a lot of research on plant pests, epidemiology and diagnostics,’ said Dr Colla. ‘These results can be used not just in terms of bioterrorism, but also for unintentional threats because we now have protocols to eradicate particular pathogens.’



Contacts and sources:
by Stephen Gillman
Horizon Magazine
European Commission Research and Innovation 

Three Super-Earths and a Small Saturn Found in Planetary System Around Dwarf Star

Astronomers from the University of Geneva (UNIGE) and members of the NCCR PlanetS have teased out a secret planetary system hiding in the arms of Cassiopea, just 21 light years away from us.

Hot, Rocky World:  This artist's rendition shows one possible appearance for the planet HD 219134b, the nearest rocky exoplanet found to date outside our solar system. The planet is 1.6 times the size of Earth, and whips around its star in just three days. Scientists predict that the scorching-hot planet -- known to be rocky through measurements of its mass and size -- would have a rocky, partially molten surface with geological activity, including possibly volcanoes. 

Image credit: NASA/JPL-Caltech

 The remarkable system, named HD219134, hosts one outer giant planet and three inner super-Earths, one of which transits in front of the star. The transiting super-Earth has a density similar to the Earth’s. It is by far the closest transiting planet known today. It provides the ideal candidate for follow-up studies and a deeper understanding of planetary formation, internal composition, and atmospheres. The system is so close that astronomers already dream about taking pictures of the new “Stars”.

HARPS-N, the northern twin sister of the famous planet hunter HARPS, designed and built by an international consortium led by researchers at the Geneva University and installed at the Telescopio Nazionale Galileo on the La Palma island, just unveiled an exceptional planetary system around HD219134. The star, a 5th magnitude K dwarf, slightly colder and less massive than our Sun, is so bright that we can follow her with a naked eye with a naked eye from dark skies, next to one leg of the W-shape Cassiopeia constellation, all year round in our boreal hemisphere. The cortege of planets is composed of three mostly rocky super-Earths and an outer giant planet, a configuration reminiscent of our own Solar System.

A super-Earth with terrestrial density revealed by Spitzer observations

“When the first HARPS-N radial-velocity measurements indicated the presence of a 3-day planet around HD219134, we immediately asked NASA for Spitzer space telescope time” explains a smiling Ati Motalebi, astronomer at UNIGE and first author of the paper describing the discovery to appear in one of the coming issues of the Astronomy & Astrophysics journal. “The idea was to check for a potential transit of the planet in front of the star, a mini eclipse, that would allow us to measure the size of the planet,” she continues, “to do this, we needed to go to space to reach the required precision”. Fortune favours the brave; HD219134b does indeed transit the star. 

It is by far the closest transiting planet known, and likely to remain one of the closest ever. The mass of the planet obtained from the ground-based radial velocities, combined with the planet radius derived from space observations with Spitzer, yield the mean density of the planet. HD219134b is a 4.5 times more massive than the Earth and 1.6 times larger, what planet hunters call a super-Earth. Its mean density is close to the density of the Earth, suggesting a possibly similar composition as well.

Two additional super-Earths and a giant planet

But, there is more! The team discovered three additional longer-period planets in the system from the HARPS-N radial velocities. In the inner regions, a planet weighing 2.7 times the Earth orbits HD219134 in 6.8 days, and a planet of 8.7 times the mass of the Earth resides on a 46.8-day orbit. If, by chance, these 2 planets would be in a coplanar configuration with their 3rd inner sister, as often observed for compact systems, the whole family might be transiting. 

Motivated by this exciting perspective, future observations to capture the potential transits have already been organized. “In particular, the future CHEOPS satellite of the European Space Agency (ESA), developed under Swiss leadership with a strong involvement of UNIGE and of the University of Bern, will provide the perfect tool for such observations” comments with enthusiasm Prof Stéphane Udry from the Geneva University, who is further adding that “being able to characterise three transiting super-Earths in a single bright and close system would provide incomparable constraints for planet formation and composition models, in particular for super-Earths”. The story does not stop here, yet. 

The system includes as well a giant planet (of small-Saturn type) at 2.1 astronomical units, orbiting the star in a bit more than 3 years. This system, reminiscent of our own Solar System with the inner “small” planets and the outer gaseous one, will without doubt encounter a growing interest from the astronomical community. Indeed, the proximity and brightness of the star makes the system the most favourable one for an in-depth characterisation of the planet physical properties. 

For atmospheric studies, astronomers are already planning observations with ground-based high-resolution spectrographs and the future NASA-ESA James Webb Space telescope (JWST) using transmission spectroscopy techniques; during the transit the light of the star crosses the atmosphere of the planet on its way to the observer, carrying over the spectral signature of the chemical species present in the atmosphere. They even dream about direct imaging of the outer planet in the system with the new generation of giant telescopes on the ground, the Extremely Large Telescopes, planned for the next decade.


Contacts and sources: 
Geneva University

Ebola Vaccine Test Successfu

A vaccine against the Ebola virus, tested in West Africa for the first time in a field trial, has proved to be effective. People who had come into close contact with someone recently infected, and who are therefore at particularly high risk, were vaccinated. Investigators from the University of Bern were heavily involved in designing the World Health Organization (WHO) "Ebola ça Suffit" vaccine trial.

 


The Ebola virus disease epidemic in West Africa has not been defeated yet, although the number of cases has dropped substantially since the start of the year. Just one Ebola case in the most heavily affected countries, Guinea, Liberia and Sierra Leone, can lead to a resurgence. Two vaccines that were recently developed have already undergone preliminary tests in humans. One of the vaccines, "rVSV-ZEBOV", has now been tested in the first large field trial of efficacy and effectiveness in Guinea, West Africa.

Prof. Dr. Matthias Egger from the Institute of Social and Preventive Medicine at the University of Bern was involved in this "Ebola ça Suffit" trial, together with PD Dr. Sven Trelle and other staff from the Clinical Trials Unit CTU Bern at the University’s clinical study centre and Bern University Hospital. The initial results of the study show that the vaccine can effectively contain the further spread of the Ebola virus. The results of the field study and the innovative study methods were published in the "Lancet" and "BMJ" scientific journals.

Protective rings against Ebola

The international group of researchers used a multi-stage approach to test the efficacy of the vaccine. Their strategy was based on "ring vaccination," which was used to eradicate smallpox in Africa in the 1970s. The first step identified people who had been in close contact, within the last 21 days, with a person who had recently contracted Ebola and were therefore directly at risk of infection; close contacts included family members, household members or nursing staff. The second step identified people who were indirectly at risk, for example the neighbours or work colleagues of a close contact. These contacts are also part of the «ring». People in the ring and eligible to receive the vaccine were asked for consent to take part in the trial.

Anyone who had contracted Ebola before, children, pregnant women and women still breastfeeding, the seriously ill and people with immune deficiencies or allergic reactions to vaccines were excluded from the study. Ninety rings in total could be defined and examined in the period from April to July 2015. The rings consisted of 7,651 contacts, of whom 5,415 were eligible for vaccination. 3,512 (65 percent) of these could in turn be vaccinated.

The rings were randomly allocated to two groups of equal size: individuals in the first group were vaccinated immediately, the others after a waiting period of 21 days, the incubation period of Ebola. It was therefore expected that some of the people in the second group would contract Ebola.

"Unfortunately this is the only way to test whether the vaccine really works," Matthias Egger says. The results showed that those vaccinated immediately were fully protected one week after vaccination, whereas 16 Ebola cases were observed in the group with delayed vaccination. These cases were all either contracted before or within six days after the delayed vaccination. There were no new Ebola cases thereafter.

«We can therefore say that the vaccine offers 100% protection against Ebola after roughly one week», Sven Trelle says. Overall the protective effect within the rings, in which there were also people who had not been vaccinated, was still 76 percent, which means the transmission of the virus could be interrupted in many cases. "It is not just the efficacy of the Ebola vaccine that has now been shown but also the effectiveness of the ring vaccination strategy,"  Egger explains with delight. "This could finally be the beginning of the end of the Ebola epidemic in West Africa and also be useful when combating this disease in the future."






Contacts and sources:
University of Bern 


Henao, Longini, Egger et al.: Efficacy and effectiveness of a rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomized trial, Lancet, 31.7.2015, in press

Publikation im British Medical Journal: The ring vaccination trial: a novel cluster randomised controlled trial design to evaluate vaccine efficacy and effectiveness during outbreaks, with special reference to Ebola
BMJ 2015; 351 doi: http://dx.doi.org/10.1136/bmj.h3740 (Published 27 July 2015), BMJ 2015;351:h3740 Erhältlich unter http://www.bmj.com/content/351/bmj.h3740

Entire Ecosystem Threatened by Climate Change Effects

Several rare upland bird species are being put at risk together with other ecosystem functions by the effects of climate change on the UK’s blanket bogs, ecologists at the University of York have discovered.



Most of our drinking water comes from these upland peats and several iconic bird species such as the dunlin, golden plover and red grouse depend on these wetland habitats for nesting and feeding.

The scientists warn that climate change threatens these habitats, not only from rising temperatures increasing peat decomposition, but also via altered rainfall patterns – with summer droughts drastically affecting the blanket bog hydrology.

The study, which involved collaboration with British Trust for Ornithology, Aberystwyth University and the University of Leeds and part-funded by the RSPB, showed that the humble crane fly, more commonly known as ‘daddy longlegs’, is a crucial link in determining the impact of climate change on these peatland bird species.

The birds depend on the protein rich crane flies as food for chicks, but scientists have discovered that summer droughts, which are predicted to increase, will cause significant declines in crane flies and subsequently the bird species that depend on them.

Based on a peatland model developed at the University of York and latest climate change predictions, the researchers warn that by 2051-80 the dunlin could see a 50% decline in numbers, with the golden plover down 30% and the red grouse down by 15%, all driven by declining abundance of the birds’ crane fly prey.

The findings, part of a PhD by Dr Matthew Carroll supervised by Professor Chris Thomas at the Biology Department at the University of York, highlight the complex relationship between climate, bog habitats, insects, and birds.

It suggests that large-scale projects to restore degraded and eroded blanket bogs could be critical in securing the future of these internationally important bird populations, alongside both water supplies and the crucial role of blanket bogs as a carbon store.

The results have been published in Nature Communications.

Dr Andreas Heinemeyer from the Stockholm Environment Institute (SEI) based at the University of York, who developed the peatland model, said: “This is one of the first studies to follow this bug-to-bird link, down the food chain, between climate change and something happening to an entire eco-system with relevance to people.”

“There is a very strong relationship between the moisture of the peat and the survival of the larvae of the crane fly during summer. July and August are peak times: if it is too dry, the larvae just desiccate and die and are then not available for the bird chicks the following year. “

The crane fly link was made as part of several longer-term studies – funded by The Natural Environment Research Council and Defra - investigating blanket bog ecosystems across several UK upland sites, including the Yorkshire Dales, Peak District and North York Moors.

Dr Heinemeyer, who is currently leading a £1m Defra-funded SEI project to further study the impacts of climate change and management on blanket bogs, said it wasn’t only rare birds that were at risk from climate change.

“We might be in for big change. Not just in connection with our birds, but our drinking water as well,” he added “If you end up being very dry as a blanket bog you store less water and your water quality seems to deteriorate as peat erodes and decomposes. So there seems to be a link, but it’s not an easy link.

“It is a very messy picture as vegetation and bugs are also involved and everything works together like a jigsaw puzzle. If you change a piece, you will change others around it.”

Dr Carroll, RSPB Conservation Scientist, said: “Our work shows that climate change could harm some of our most iconic upland bird species. The birds rely on crane flies for food during the breeding season, and the crane flies rely on the cool, wet conditions in blanket bogs.

“Large-scale peatland restoration projects such as the Sustainable Catchment Management Project run by United Utilities and RSPB are crucial in helping to make our blanket bogs resilient to climate change.”


Contacts and sources:
Alistair Keely
University of York 

Sugar in Coffee and Tea Influences Fundamental Chemistry

New research by a University of York scientist has given tea and coffee drinkers new information about why their favorite drinks taste as they do.



The study by Dr Seishi Shimizu, of the York Structural Biology Laboratory in the University’s Department of Chemistry, shows that sugar has an important effect in reducing the bitterness of tea and coffee, not just by masking it but by influencing the fundamental chemistry.

The research published in Food and Function reveals new insights into the way in which caffeine, sugar and water interact at the molecular level to affect the taste of hot beverages.

Appreciated for its “reviving” stimulant effect, caffeine is, however, also in part responsible for the bitter taste in tea and coffee. The caffeine molecules tend to stick to each other when in water, and this tendency is further enhanced by the addition of sugar. For many decades, scientists have assumed that this was due to the strengthening of bonds between water molecules around the sugar.

But Dr Shimizu’s research instead suggests that the underlying cause is the affinity between sugar molecules and water, which in turn makes the caffeine molecules stick together (or aggregate) in order to avoid the sugar. This is why we experience less of their bitter taste. Proper understanding of the fundamental rationale behind this process may assist food scientists in many ways.

He used statistical thermodynamics – a branch of theoretical physical chemistry linking the microscopic realm with the everyday world – to investigate the molecular-level activities and interactions behind our daily food and drink.

Dr Shimizu says: "It is delightful indeed that food and drink questions can be solved using theory, with equipment no more complex than a pen and paper. Encouraged by this discovery, and our recent success on how to make jelly firmer, we are working hard to reveal more about the molecular basis of food and cooking."



Contacts and sources:
David GarnerUniversity of York 

Organic Molecules Found on Comet, Key Elements in the Formation of Life on Earth

Scientists at The Open University (OU) have published their first findings from Ptolemy, their gas analysis instrument on the Rosetta spacecraft’s lander Philae which landed on a comet last November. Analysis of the comet’s dust particles collected by Ptolemy has revealed the presence of organic compounds – key elements in the formation of life on Earth.

Comet 67P/Churyumov-Gerasimenko 
Credit; ESA/Rosetta/NAVCAM

Ptolemy sprang into action when Philae bounced off Comet 67P/Churyumov-Gerasimenko last November. The lander kicked up a dust cloud which enabled Ptolemy – the gas analysis instrument on board, to sniff the particles on the surface. Ptolemy detected compounds containing carbon, hydrogen and oxygen – all of which are key elements in the formation of water and simple sugars. The compounds detected are not biogenic in nature and therefore do not indicate signs of life. According to Ian Wright, OU Professor of Planetary Sciences and Principal Investigator on Ptolemy, the compounds found are elements that "will have gone into the mix that led to the formation of the life on Earth".

Not only has Ptolemy’s first analysis given scientists insight into what comets are made of, it has also revealed more about what chemical reactions occur on the surface. Ptolemy investigator Dr Andrew Morse said: "We now know more about the surface of comet 67P that we ever did before. Findings such as the fact that its surface is soft and dusty, but beneath that is hard layer of ice, will play an important part to inform plans for future comet landings and space exploration."

Last month Philae tweeted back to Earth that it was alive and well after its solar-powered batteries ran down due to lack of sunlight. Now that the lander is awake scientists at the OU, and across Europe, are hoping that it will be able to continue capturing data about the comet and transmitting it back to Earth. 

Professor Wright added: “We’re incredibly excited by these findings. As this was the first ever attempt to land on a comet to do science, we had very limited knowledge about what to expect. Ptolemy, like all of the instruments on board, was designed to be as flexible as possible to adapt to the hostile environment in space. The fact that it has managed to capture this data and transmit it back to us despite such a tumultuous landing is incredible.”





Contacts and sources:
The Open University (OU)

The paper ‘CHO-bearing organic compounds at the surface of 67P/Churyumov-Gerasimenko revealed by Ptolemy’ was published in Science magazine. It was authored by the OU Ptolemy team which consists of Dan Andrews, Simeon Barber, Geraint Morgan, Andrew Morse and Simon Sheridan, and is led by Professor Ian Wright.
http://www.sciencemag.org/content/349/6247/aab0673.abstract

Why Do We Age? A Step Closer to the Answer

The question of why we age is one of the most fascinating questions for humankind, but nothing close to a satisfactory answer has been found to date. Scientists at the Leibniz-Institut für Molekulare Pharmakologie in Berlin have now taken one step closer to providing an answer. They have conducted a study in which, for the first time, they have shown that a certain area of the cell, the so-called endoplasmic reticulum, loses its oxidative power in advanced age. If this elixir of life is lost, many proteins can no longer mature properly. At the same time, oxidative damage accumulates in another area of the cell, the cytosol. This interplay was previously unknown and now opens up a new understanding of ageing, but also of neurodegenerative diseases such as Alzheimer's or Parkinson's.

Using genetically encoded sensors this study shows that the opposing redox state in ER lumen and cytosol is altered during ageing and upon disruption of proteostasis. The resulting redox imbalance can spread across tissues. 

Credit: © FMP

Each cell consists of different compartments. One of them is the endoplasmic reticulum (ER). Here, , proteins which are then secreted e.g. into the bloodstream, such as insulin or antibodies of the immune system, mature in an oxidative environment. A type of quality control, so-called redox homoeostasis, ensures that the oxidative milieu is maintained and disulphide bridges can form. Disulphide bridges form and stabilise the three-dimensional protein structure and are thus essential for a correct function of the secretory proteins, e.g. those migrating into the blood.

Equilibrium thrown off balance

Scientists at the Leibniz-Institut für Molekulare Pharmakologie in Berlin have now shown, for the first time, that the ER loses its oxidative power in advanced age, which shifts the reducing/oxidising equilibrium – redox for short – in this compartment. This leads to a decline in the capacity to form the disulphide bridges that are so important for correct protein folding. As a consequence, many proteins can no longer mature properly and become unstable.

Although, it was already known that increased protein misfolding occurs with the progression of ageing, it was not known whether the redox equilibrium is affected. Likewise, it was not known that the loss of oxidative power in the ER also affects the equilibrium in another compartment of the cell: in reverse, namely, the otherwise protein-reducing cytosol becomes more oxidising during ageing, which leads to the known oxidative protein damage such those caused by the release of free radicals.

"Up to now, it has been completely unclear what happens in the endoplasmic reticulum during the ageing process. We have now succeeded in answering this question," says Dr. Janine Kirstein, first author of the study, which has been published in EMBO Journal*. At the same time, the scientists were able to show that there is a strong correlation between protein homoeostasis and redox equilibrium. "This is absolutely new and helps us to understand why secretory proteins become unstable and lose their function in advanced age and after stress. This may explain why the immune response declines as we get older," the biologist explains further.

Stress has the same effects as ageing

The researchers also demonstrated the decline of the oxidative milieu of the ER after stress. When they synthesised amyloid protein fibrils in the cell, which cause diseases such as Alzheimer's, Parkinson's or Huntington's disease, they set the same cascade in motion. Apart from this, they were able to show that amyloids that are synthesised in a certain tissue also have negative effects on the redox equilibrium in another tissue within the same organism. "Protein stress leads to the same effects as ageing," explains Kirstein. "Our findings are thus not only interesting with regards to ageing, but also concerning neurodegenerative diseases such as Alzheimer's."

The image depicts a single nematode muscle cell, which synthesises the fluorescence sensor redox-GFP in the endoplasmic reticulum. The sensor is excited with a laser of two different wavelengths. Green areas reflect reducing conditions and blue areas oxidising conditions. scale bar 10 µm. 
Photo: FMP/Janine Kirstein

For their experiments, the team of researchers used nematodes - an established model system for investigating ageing processes on a molecular level. Since the nematode is transparent, the researchers were able to use fluorescence-based sensors in order to measure oxidation in the individual cell compartments. It was thus possible to track precisely in the living nematode how the redox condition changes with advancing age. In addition, the influence of protein aggregation on the redox homeostasis was investigated in cultivated cells of human origin. The data were fully consistent with those from the nematode.

Using the findings to identify new diagnostic biomarkers

"We gained a lot of insight, but have also learned that ageing is much more complex than previously assumed," stresses the biologist Kirstein. Thus, for example, the mechanism of the signal transduction of protein folding stress to the redox equilibrium – both within the cell from one compartment to another and also between two different tissues – remains completely unclear.

Nevertheless, research of ageing has taken a major step forward as a result of the findings from Berlin, particularly since it promises a practical benefit. The redox equilibrium may serve as a basis for new biomarkers for diagnosing both ageing and neurodegenerative processes in the future. Janine Kirstein: "The approach is less likely to be useful for therapeutic purposes at present, but the development of diagnostic tools is certainly conceivable." 

The project is a cooperation between laboratories from Berlin, Chicago, Kyoto and Munich.



Contacts and sources:
Forschungsverbund Berlin e.V. (FVB)

Ocean Currents Offer Insights into MH370

Preliminary insights into the potential pathway of the plane wreckage that washed up on Reunion Island yesterday morning, thought to be from the missing MH370 flight, is provided by researchers at the National Oceanography Centre (NOC).

If a plane crashed into the South East Indian Ocean, any debris floating on the surface could have ended up on Reunion by one of two possible scenarios.

Surface current simulation from NEMO


In the first scenario it would have initially been carried northwards in a large ‘round-a-bout’ system of currents in the South Indian Ocean – called a ‘subtropical gyre’. It would have then been swept westward, towards Reunion Island, in a relatively fast moving band of water known as the South Equatorial Current. This westward flowing water moves across the entire Southern Indian Ocean at the same latitude as northern Madagascar but can be partly deflected towards Reunion when it meets the Mascarene Plateau near 60°E. The speed of this current varies, although it can reach up to 50 centimetres a second.

An analysis of a global ocean simulation, provided by the NEMO model, gives rise to the second scenario. In this situation it appears possible that the debris could have been carried more or less directly westwards by a complex pattern of swirling currents, which include features known as “eddies”. These are rotary current structures which travel slowly westwards.

The likely timescales for these routes could be between one year for the more northerly route and two years for the directly westward route. More detailed analysis is currently underway at the NOC, including the direct tracking of surface floating particles, to confirm the likelihoods of these pathways and timescales.

The NEMO ocean model was developed by an international consortium, including the NOC. The model provides full depth coverage of ocean currents, temperatures and salinities. It has also been used to track the movements of oil spills.

Professor Adrian New, an expert in Indian Ocean currents at the NOC, said that the discovery of the plane wreckage in Reunion might be consistent with a possible crash site in the South-East Indian Ocean though other crash sites cannot definitely be ruled out.



Contacts and sources:
National Oceanography Centre (NOC)

Countering Pet Obesity by Rethinking Feeding Habits

190 million Americans share the luxuries of human life with their pets. Giving dogs and cats a place in human homes, beds and--sometimes even, their wills--comes with the family member package.

Amongst these shared human-pet comforts is the unique luxury to overeat. As a result, the most common form of malnutrition for Americans and their companion animals results not from the underconsumption, but the overconsumption of food. The obesity epidemic also causes a similar array of diseases in people and pets: diabetes, hyperlipidemia and cancer.

Obese Chihuahua
Credit: Flickr 

During this year's ADSA-ASAS Joint Annual Meeting, five companion animal nutrition experts from around the world further examined the implications of over- or inaccurately feeding cats and dogs. "Companion Animal Symposium: Bioenergetics of pet food" was a part of the Companion Animal Science Program, an event sponsored annually by the George Fahey Appreciation Club.

Bioenergetics concern energy flow through living systems. Since obesity results from an imbalance of energy use and intake, bioenergetics help scientists understand the correlation between overweight animals and the food they consume.

The most definitive player in pet health is the owner. Dr. Kelly Swanson, Professor of Animal and Nutritional Sciences at the University of Illinois, says the first step in combating pet obesity is simply realizing that an animal is overweight.

"Owners need to actually recognize that their pet is obese, and is not just a funny, pudgy animal that looks cute," said Swanson. "Lean, healthy pets not only live longer, but more importantly, have a better quality of life."

In fact, some lifelong studies show that maintaining a lean body condition score (BCS 4 or 5) adds an average of 1.8 years to dogs' lives. Preserving steady body conditions requires owners to not just read pet food labels, but to actually understand and apply the feeding directions.

Food types and feeding frequencies also need to vary from animal to animal. Dr. Dennis Jewell, Research Scientist at Hill's Pet Nutrition, emphasized the customization of feeding programs to fit each individual.

"Each pet has unique genetics that determine, for example, if they're going to use more calories to maintain their body weight than other animals," said Jewell. "We can design feeding programs for specific pet populations - based on factors like age, size, et cetera - but feeding regimens still come down to the individual pet."

For example, weight-loss regimens equate to the feeding of less energy-dense and more fiber-dense diets. Increased fiber intake results in less ad-libitum food consumption.

One overlooked feeding strategy may lie in the nature of the food itself. According to Dr. Katherine Kerr, Post-Doctoral Research Fellow at the University of Florida, raw and whole-prey diets may provide a viable alternative to extruded ones. Her projects primarily focus on the eating patterns and nutritional health of African wildcats.

"While observing feeding behaviors, we soon recognized that felines aren't physiologically made to chew," said Kerr. "When feeding whole prey, they basically just crush the skull and swallow it whole."

The diets of wild-type cats include the hide, hair and bones of prey. When used in addition to other plant and animal fibers, these have a positive impact on energy metabolism and gut microbial populations. Meat-based and whole prey diets in domestic pets could yield similar results.

Kerr says that these types of diets are undervalued and under-researched nutritional therapy options. She believes they can play an essential role in health maintenance, and disease, allergy and obesity mitigation.

"The question, 'Should we mimic nature?' is often controversial," said Kerr. "We need to explore these diets more to find out the answer."




Contacts and sources:
Jacquelyn Prestegaard
American Society of Animal Science



Read the abstracts of the Companion Animal Symposium, "Bioenergetics of pet food" athttp://www.jtmtg.org/JAM/2015/abstracts/581.pdf.

Friday, July 31, 2015

Death Throes of a Dying Star Captured by Hubble Space Telescope

A dying star’s final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star’s demise is still quite lengthy by our standards, lasting tens of thousands of years!

Image credit: ESA/Hubble & NASA, Acknowledgement: Matej Novak

The star’s agony has culminated in a wonderful planetary nebula known as NGC 6565, a cloud of gas that was ejected from the star after strong stellar winds pushed the star’s outer layers away into space. Once enough material was ejected, the star’s luminous core was exposed, enabling its ultraviolet radiation to excite the surrounding gas to varying degrees and causing it to radiate in an attractive array of colors. These same colors can be seen in the famous and impressive Ring Nebula (heic1310), a prominent example of a nebula like this one.

Planetary nebulae are illuminated for around 10,000 years before the central star begins to cool and shrink to become a white dwarf. When this happens, the star’s light drastically diminishes and ceases to excite the surrounding gas, so the nebula fades from view.



Contacts and sources:
Ashley Morrow, NASA
Text credit: European Space Agency

Distant Uranus-Sized Planet Found Through Microlensing

NASA's Hubble Space Telescope and the W. M. Keck Observatory in Hawaii have made independent confirmations of an exoplanet orbiting far from its central star. The planet was discovered through a technique called gravitational microlensing.

This graphic illustrates how a star can magnify and brighten the light of a background star when it passes in front of the distant star. If the foreground star has planets, then the planets may also magnify the light of the background star, but for a much shorter period of time than their host star. Astronomers use this method, called gravitational microlensing, to identify planets.
Credit: NASA, ESA, and A. Feild (STScI)

This finding opens a new piece of discovery space in the extrasolar planet hunt: to uncover planets as far from their central stars as Jupiter and Saturn are from our sun. The Hubble and Keck Observatory results will appear in two papers in the July 30 edition of The Astrophysical Journal.

The large majority of exoplanets cataloged so far are very close to their host stars because several current planet-hunting techniques favor finding planets in short-period orbits. But this is not the case with the microlensing technique, which can find more distant and colder planets in long-period orbits that other methods cannot detect.

Microlensing occurs when a foreground star amplifies the light of a background star that momentarily aligns with it. If the foreground star has planets, then the planets may also amplify the light of the background star, but for a much shorter period of time than their host star. The exact timing and amount of light amplification can reveal clues to the nature of the foreground star and its accompanying planets.

The system, cataloged as OGLE-2005-BLG-169, was discovered in 2005 by the Optical Gravitational Lensing Experiment (OGLE), the Microlensing Follow-Up Network (MicroFUN), and members of the Microlensing Observations in Astrophysics (MOA) collaborations — groups that search for extrasolar planets through gravitational microlensing.

Without conclusively identifying and characterizing the foreground star, however, astronomers have had a difficult time determining the properties of the accompanying planet. Using Hubble and the Keck Observatory, two teams of astronomers have now found that the system consists of a Uranus-sized planet orbiting about 370 million miles from its parent star, slightly less than the distance between Jupiter and the sun. The host star, however, is about 70 percent as massive as our sun.

"These chance alignments are rare, occurring only about once every 1 million years for a given planet, so it was thought that a very long wait would be required before the planetary microlensing signal could be confirmed," said David Bennett of the University of Notre Dame, Indiana, the lead of the team that analyzed the Hubble data. "Fortunately, the planetary signal predicts how fast the apparent positions of the background star and planetary host star will separate, and our observations have confirmed this prediction. The Hubble and Keck Observatory data, therefore, provide the first confirmation of a planetary microlensing signal."

In fact, microlensing is such a powerful tool that it can uncover planets whose host stars cannot be seen by most telescopes. "It is remarkable that we can detect planets orbiting unseen stars, but we'd really like to know something about the stars that these planets orbit," explained Virginie Batista of the Institut d'Astrophysique de Paris, France, leader of the Keck Observatory analysis. "The Keck and Hubble telescopes allow us to detect these faint planetary host stars and determine their properties."

Planets are small and faint compared to their host stars; only a few have been observed directly outside our solar system. Astronomers often rely on two indirect techniques to hunt for extrasolar planets. The first method detects planets by the subtle gravitational tug they give to their host stars. In another method, astronomers watch for small dips in the amount of light from a star as a planet passes in front of it.

Both of these techniques work best when the planets are either extremely massive or when they orbit very close to their parent stars. In these cases, astronomers can reliably determine their short orbital periods, ranging from hours to days to a couple years.

But to fully understand the architecture of distant planetary systems, astronomers must map the entire distribution of planets around a star. Astronomers, therefore, need to look farther away from the star-from about the distance of Jupiter is from our sun, and beyond.

"It's important to understand how these systems compare with our solar system," said team member Jay Anderson of the Space Telescope Science Institute in Baltimore, Maryland. "So we need a complete census of planets in these systems. Gravitational microlensing is critical in helping astronomers gain insights into planetary formation theories."

The planet in the OGLE system is probably an example of a "failed-Jupiter" planet, an object that begins to form a Jupiter-like core of rock and ice weighing around 10 Earth masses, but it doesn't grow fast enough to accrete a significant mass of hydrogen and helium. So it ends up with a mass more than 20 times smaller than that of Jupiter. "Failed-Jupiter planets, like OGLE-2005-BLG-169Lb, are predicted to be more common than Jupiters, especially around stars less massive than the sun, according to the preferred theory of planet formation. So this type of planet is thought to be quite common," Bennett said.

Microlensing takes advantage of the random motion of stars, which are generally too small to be noticed without precise measurements. If one star, however, passes nearly precisely in front of a farther background star, the gravity of the foreground star acts like a giant lens, magnifying the light from the background star.

A planetary companion around the foreground star can produce a variation in the brightening of the background star. This brightening fluctuation can reveal the planet, which can be too faint, in some cases, to be seen by telescopes. The duration of an entire microlensing event is several months, while the variation in brightening due to a planet lasts a few hours to a couple of days.

The initial microlensing data of OGLE-2005-BLG-169 had indicated a combined system of foreground and background stars plus a planet. But due to the blurring effects of our atmosphere, a number of unrelated stars are also blended with the foreground and background stars in the very crowded star field in the direction of our galaxy's center.

The sharp Hubble and Keck Observatory images allowed the research teams to separate out the background source star from its neighbors in the very crowded star field in the direction of our galaxy's center. Although the Hubble images were taken 6.5 years after the lensing event, the source and lens star were still so close together on the sky that their images merged into what looked like an elongated stellar image.

Astronomers can measure the brightness of both the source and planetary host stars from the elongated image. When combined with the information from the microlensing light curve, the lens brightness reveals the masses and orbital separation of the planet and its host star, as well as the distance of the planetary system from Earth. The foreground and background stars were observed in several different colors with Hubble's Wide Field Camera 3 (WFC3), allowing independent confirmations of the mass and distance determinations.

The observations, taken with the Near Infrared Camera 2 (NIRC2) on the Keck 2 telescope more than eight years after the microlensing event, provided a precise measurement of the foreground and background stars' relative motion. "It is the first time we were able to completely resolve the source star and the lensing star after a microlensing event. This enabled us to discriminate between two models that fit the data of the microlensing light curve," Batista said.

The Hubble and Keck Observatory data are providing proof of concept for the primary method of exoplanet detection that will be used by NASA's planned, space-based Wide-Field Infrared Survey Telescope (WFIRST), which will allow astronomers to determine the masses of planets found with microlensing. WFIRST will have Hubble's sharpness to search for exoplanets using the microlensing technique. The telescope will be able to observe foreground, planetary host stars approaching the background source stars prior to the microlensing events, and receding from the background source stars after the microlensing events.

"WFIRST will make measurements like we have made for OGLE-2005-BLG-169 for virtually all the planetary microlensing events it observes. We'll know the masses and distances for the thousands of planets discovered by WFIRST," Bennett explained.
 


Contacts and sources:
Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

David Bennett
University of Notre Dame, Notre Dame, Indiana

Jean-Phillipe Beaulieu
Institut d'Astrophysique de Paris, Paris, France

Thursday, July 30, 2015

New Theory on the Origin of Life

When life on Earth began nearly 4 billion years ago, long before humans, dinosaurs or even the earliest single-celled forms of life roamed, it may have started as a hiccup rather than a roar: small, simple molecular building blocks known as "monomers" coming together into longer "polymer" chains and falling apart in the warm pools of primordial ooze over and over again.

A schematic drawing of template-assisted ligation, shown in this model to give rise to autocatalytic systems
Credit:  Maslov and Tkachenko

Then, somewhere along the line, these growing polymer chains developed the ability to make copies of themselves. Competition between these molecules would allow the ones most efficient at making copies of themselves to do so faster or with greater abundance, a trait that would be shared by the copies they made. These rapid replicators would fill the soup faster than the other polymers, allowing the information they encoded to be passed on from one generation to another and, eventually, giving rise to what we think of today as life.

Or so the story goes. But with no fossil record to check from those early days, it's a narrative that still has some chapters missing. One question in particular remains problematic: what enabled the leap from a primordial soup of individual monomers to self-replicating polymer chains?

A new model published this week in The Journal of Chemical Physics, from AIP Publishing, proposes a potential mechanism by which self-replication could have emerged. It posits that template-assisted ligation, the joining of two polymers by using a third, longer one as a template, could have enabled polymers to become self-replicating.

"We tried to fill this gap in understanding between simple physical systems to something that can behave in a life-like manner and transmit information," said Alexei Tkachenko, a researcher at Brookhaven National Laboratory. Tkachenko carried out the research alongside Sergei Maslov, a professor at the University of Illinois at Urbana-Champaign with joint appointment at Brookhaven.

Origins of Self-Replication

Self-replication is a complicated process -- DNA, the basis for life on earth today, requires a coordinated cohort of enzymes and other molecules in order to duplicate itself. Early self-replicating systems were surely more rudimentary, but their existence in the first place is still somewhat baffling.

Tkachenko and Maslov have proposed a new model that shows how the earliest self-replicating molecules could have worked. Their model switches between "day" phases, where individual polymers float freely, and "night" phases, where they join together to form longer chains via template-assisted ligation. The phases are driven by cyclic changes in environmental conditions, such as temperature, pH, or salinity, which throw the system out of equilibrium and induce the polymers to either come together or drift apart.

According to their model, during the night cycles, multiple short polymers bond to longer polymer strands, which act as templates. These longer template strands hold the shorter polymers in close enough proximity to each other that they can ligate to form a longer strand -- a complementary copy of at least part of the template. Over time, the newly synthesized polymers come to dominate, giving rise to an autocatalytic and self-sustaining system of molecules large enough to potentially encode blueprints for life, the model predicts

Polymers can also link together without the aid of a template, but the process is somewhat more random -- a chain that forms in one generation will not necessarily be carried over into the next. Template-assisted ligation, on the other hand, is a more faithful means of preserving information, as the polymer chains of one generation are used to build the next. Thus, a model based on template-assisted ligation combines the lengthening of polymer chains with their replication, providing a potential mechanism for heritability.

While some previous studies have argued that a mix of the two is necessary for moving a system from monomers to self-replicating polymers, Maslov and Tkachenko's model demonstrates that it is physically possible for self-replication to emerge with only template-assisted ligation.

"What we have demonstrated for the first time is that even if all you have is template-assisted ligation, you can still bootstrap the system out of primordial soup," said Maslov.

The idea of template-assisted ligation driving self-replication was originally proposed in the 1980s, but in a qualitative manner. "Now it's a real model that you can run through a computer," said Tkachenko. "It's a solid piece of science to which you can add other features and study memory effects and inheritance."

Under Tkachenko and Maslov's model, the move from monomers to polymers is a very sudden one. It's also hysteretic -- that is, it takes a very certain set of conditions to make the initial leap from monomers to self-replicating polymers, but those stringent requirements are not necessary to maintain a system of self-replicating polymers once one has leapt over the first hurdle.

One limitation of the model that the researchers plan to address in future studies is its assumption that all polymer sequences are equally likely to occur. Transmission of information requires heritable variation in sequence frequencies -- certain combinations of bases code for particular proteins, which have different functions. The next step, then, is to consider a scenario in which some sequences become more common than others, allowing the system to transmit meaningful information.

Maslov and Tkachenko's model fits into the currently favored RNA world hypothesis -- the belief that life on earth started with autocatalytic RNA molecules that then lead to the more stable but more complex DNA as a mode of inheritance. But because it is so general, it could be used to test any origins of life hypothesis that relies on the emergence of a simple autocatalytic system.

"The model, by design, is very general," said Maslov. "We're not trying to address the question of what this primordial soup of monomers is coming from" or the specific molecules involved. Rather, their model shows a physically plausible path from monomer to self-replicating polymer, inching a step closer to understanding the origins of life.

Waiter, there's an RNA in my Primordial Soup -- Tracing the Origins of Life, from Darwin to Today

Nearly every culture on earth has an origins story, a legend explaining its existence. We humans seem to have a deep need for an explanation of how we ended up here, on this small planet spinning through a vast universe. Scientists, too, have long searched for our origins story, trying to discern how, on a molecular scale, the earth shifted from a mess of inorganic molecules to an ordered system of life. The question is impossible to answer for certain -- there's no fossil record, and no eyewitnesses. But that hasn't stopped scientists from trying.

Over the past 150 years, our shifting understanding of the origins of life has mirrored the emergence and development of the fields of organic chemistry and molecular biology. That is, increased understanding of the role that nucleotides, proteins and genes play in shaping our living world today has also gradually improved our ability to peer into their mysterious past.

When Charles Darwin published his seminal On the Origin of the Species in 1859, he said little about the emergence of life itself, possibly because, at the time, there was no way to test such ideas. His only real remarks on the subject come from a later letter to a friend, in which he suggested a that life emerged out of a "warm little pond" with a rich chemical broth of ions. Nevertheless, Darwin's influence was far-reaching, and his offhand remark formed the basis of many origins of life scenarios in the following years.

In the early 20th century, the idea was popularized and expanded upon by a Russian biochemist named Alexander Oparin. He proposed that the atmosphere on the early earth was reducing, meaning it had an excess of negative charge. This charge imbalance could catalyze existing a prebiotic soup of organic molecules into the earliest forms of life.

Oparin's writing eventually inspired Harold Urey, who began to champion Oparin's proposal. Urey then caught the attention of Stanley Miller, who decided to formally test the idea. Miller took a mixture of what he believed the early earth's oceans may have contained -- a reducing mixture of methane, ammonia, hydrogen, and water -- and activated it with an electric spark. The jolt of electricity, acting like a strike of lightening, transformed nearly half of the carbon in the methane into organic compounds. One of the compounds he produced was glycine, the simplest amino acid.

The groundbreaking Miller-Urey experiment showed that inorganic matter could give rise to organic structures. And while the idea of a reducing atmosphere gradually fell out of favor, replaced by an environment rich in carbon dioxide, Oparin's basic framework of a primordial soup rich with organic molecules stuck around.

The identification of DNA as the hereditary material common to all life, and the discovery that DNA coded for RNA, which coded for proteins, provided fresh insight into the molecular basis for life. But it also forced origins of life researchers to answer a challenging question: how could this complicated molecular machinery have started? DNA is a complex molecule, requiring a coordinated team of enzymes and proteins to replicate itself. Its spontaneous emergence seemed improbable.

In the 1960s, three scientists -- Leslie Orgel, Francis Crick and Carl Woese -- independently suggested that RNA might be the missing link. Because RNA can self-replicate, it could have acted as both the genetic material and the catalyst for early life on earth. DNA, more stable but more complex, would have emerged later.

Today, it is widely believed (though by no means universally accepted) that at some point in history, an RNA-based world dominated the earth. But how it got there -- and whether there was a simpler system before it -- is still up for debate. Many argue that RNA is too complicated to have been the first self-replicating system on earth, and that something simpler preceded it.

Graham Cairns-Smith, for instance, has argued since the 1960s that the earliest gene-like structures were not based on nucleic acids, but on imperfect crystals that emerged from clay. The defects in the crystals, he believed, stored information that could be replicated and passed from one crystal to another. His idea, while intriguing, is not widely accepted today.

Others, taken more seriously, suspect that RNA may have emerged in concert with peptides -- an RNA-peptide world, in which the two worked together to build up complexity. Biochemical studies are also providing insight into simpler nucleic acid analogs that could have preceded the familiar bases that make up RNA today. It's also possible that the earliest self-replicating systems on earth have left no trace of themselves in our current biochemical systems. We may never know, and yet, the challenge of the search seems to be part of its appeal.

Recent research by Tkachenko and Maslov, published July 28, 2015 in The Journal of Chemical Physics, suggests that self-replicating molecules such as RNA may have arisen through a process called template-assisted ligation. That is, under certain environmental conditions, small polymers could be driven to bond to longer complementary polymer template strands, holding the short strands in close enough proximity to each other that they could fuse into longer strands. Through cyclic changes in environmental conditions that induce complementary strands to come together and then fall apart repeatedly, a self-sustaining collection of hybridized, self-replicating polymers able to encode the blueprints for life could emerge.


Contacts and sources:
American Institute of Physics (AIP)

Citation:  "Spontaneous emergence of autocatalytic information-coding polymers," is authored by Alexei Tkachenko and Sergei Maslov. It will appear in The Journal of Chemical Physics on July 28, 2015.  http://scitation.aip.org/content/aip/journal/jcp/143/4/10.1063/1.4922545


The Journal of Chemical Physics publishes concise and definitive reports of significant research in the methods and applications of chemical physics.


California “Rain Debt” Equal to Average Full Year of Precipitation

A new NASA study has concluded California accumulated a debt of about 20 inches of precipitation between 2012 and 2015 -- the average amount expected to fall in the state in a single year. The deficit was driven primarily by a lack of air currents moving inland from the Pacific Ocean that are rich in water vapor.

California's accumulated precipitation “deficit” from 2012 to 2014 shown as a percent change from the 17-year average based on TRMM multi-satellite observations.
Credits: NASA/Goddard Scientific Visualization Studio

In an average year, 20 to 50 percent of California's precipitation comes from relatively few, but extreme events called atmospheric rivers that move from over the Pacific Ocean to the California coast.

"When they say that an atmospheric river makes landfall, it's almost like a hurricane, without the winds. They cause extreme precipitation," said study lead author Andrey Savtchenko at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Savtchenko and his colleagues examined data from 17 years of satellite observations and 36 years of combined observations and model data to understand how precipitation has varied in California since 1979. The results were published Thursday in Journal of Geophysical Research – Atmospheres, a journal of the American Geophysical Union.

The state as a whole can expect an average of about 20 inches of precipitation each year, with regional differences. But, the total amount can vary as much as 30 percent from year to year, according to the study.

In non-drought periods, wet years often alternate with dry years to balance out in the short term. However, from 2012 to 2014, California accumulated a deficit of almost 13 inches, and the 2014-2015 wet season increased the debt another seven inches, for a total 20 inches accumulated deficit during the course of three dry years.

The majority of that precipitation loss is attributed to a high-pressure system in the atmosphere over the eastern Pacific Ocean that has interfered with the formation of atmospheric rivers since 2011.

Atmospheric rivers occur all over the world. They are narrow, concentrated tendrils of water vapor that travel through the atmosphere similar to, and sometimes with, the winds of a jet stream. Like a jet stream, they typically travel from west to east. The ones destined for California originate over the tropical Pacific, where warm ocean water evaporates a lot of moisture into the air. The moisture-rich atmospheric rivers, informally known as the Pineapple Express, then break northward toward North America.

The atmospheric rivers that drenched California in December 2014 are shown in this data visualization: water vapor (white) and precipitation (red to yellow).

Credits: NASA/Goddard Scientific Visualization Studio

Earlier this year, a NASA research aircraft participated in the CalWater 2015 field campaign to improve understanding of when and how atmospheric rivers reach California.

Some of the water vapor rains out over the ocean, but the show really begins when an atmospheric river reaches land. Two reached California around Dec. 1 and 10, 2014, and brought more than three inches of rain, according to NASA's Tropical Rainfall Measuring Mission (TRMM)'s multi-satellite dataset. The inland terrain, particularly mountains, force the moist air to higher altitudes where lower pressure causes it to expand and cool. The cooler air condenses the concentrated pool of water vapor into torrential rains, or snowfall as happens over the Sierra Nevada Mountains, where water is stored in the snowpack until the spring melt just before the growing season.

The current drought isn't the first for California. Savtchenko and his colleagues recreated a climate record for 1979 to the present using the Modern-Era Retrospective Analysis for Research and Applications, or MERRA. Their efforts show that a 27.5 inch deficit of rain and snow occurred in the state between 1986 and 1994.

"Drought has happened here before. It will happen again, and some research groups have presented evidence it will happen more frequently as the planet warms," Savtchenko said. "But, even if the climate doesn’t change, are our demands for fresh water sustainable?"

The current drought has been notably severe because, since the late 1980s, California's population, industry and agriculture have experienced tremendous growth, with a correlating growth in their demand for water. Human consumption has depleted California's reservoirs and groundwater reserves, as shown by data from NASA's Gravity Recovery and Climate Experiment (GRACE) mission, leading to mandatory water rationing.

"The history of the American West is written in great decade-long droughts followed by multi-year wet periods," said climatologist Bill Patzert at NASA's Jet Propulsion Laboratory in Pasadena, California. He was not involved in the research. "Savtchenko and his team have shown how variable California rainfall is.”

According to Patzert, this study added nuance to how scientists may interpret the atmospheric conditions that cause atmospheric rivers and an El Niño's capacity to bust the drought. Since March, rising sea surface temperatures in the central equatorial Pacific have indicated the formation of El Niño conditions. El Niño conditions are often associated with higher rainfall to the western United States, but it’s not guaranteed.

Savtchenko and his colleagues show that El Niño contributes only six percent to California's precipitation variability and is one factor among other, more random effects that influence how much rainfall the state receives. While it’s more likely El Niño increases precipitation in California, it’s still possible it will have no, or even a drying, effect.

A strong El Niño that lasts through the rainy months, from November to March, is more likely to increase the amount of rain that reaches California, and Savtchenko noted the current El Niño is quickly strengthening.

The National Oceanic and Atmospheric Administration (NOAA), which monitors El Niño events, ranks it as the third strongest in the past 65 years for May and June. Still, it will likely take several years of higher than normal rain and snowfall to recover from the current drought.

"If this El Niño holds through winter, California’s chances to recoup some of the precipitation increase. Unfortunately, so do the chances of floods and landslides," Savtchenko said. “Most likely the effects would be felt in late 2015-2016.”


Contacts and sources: 

Helium-Shrouded Planets May Be Common in Our Galaxy

They wouldn't float like balloons or give you the chance to talk in high, squeaky voices, but planets with helium skies may constitute an exotic planetary class in our Milky Way galaxy. Researchers using data from NASA's Spitzer Space Telescope propose that warm Neptune-size planets with clouds of helium may be strewn about the galaxy by the thousands.

This artist's concept depicts a proposed helium-atmosphere planet called GJ 436b, which was found by Spitzer to lack in methane -- a first clue about its lack of hydrogen.

Credits: NASA/JPL-Caltech

"We don't have any planets like this in our own solar system," said Renyu Hu, NASA Hubble Fellow at the agency's Jet Propulsion Laboratory in Pasadena, California, and lead author of a new study on the findings accepted for publication in the Astrophysical Journal. "But we think planets with helium atmospheres could be common around other stars."

Prior to the study, astronomers had been investigating a surprising number of so-called warm Neptunes in our galaxy. NASA's Kepler space telescope has found hundreds of candidate planets that fall into this category. They are the size of Neptune or smaller, with tight orbits that are closer to their stars than our own sizzling Mercury is to our sun. These planets reach temperatures of more than 1,340 degrees Fahrenheit (1,000 Kelvin), and orbit their stars in as little as one or two days.

In the new study, Hu and his team make the case that some warm Neptunes -- and warm sub-Neptunes, which are smaller than Neptune -- could have atmospheres enriched with helium. They say that the close proximity of these planets to their searing stars would cause the hydrogen in their atmospheres to boil off.

"Hydrogen is four times lighter than helium, so it would slowly disappear from the planets' atmospheres, causing them to become more concentrated with helium over time," said Hu. "The process would be gradual, taking up to 10 billion years to complete." For reference, our planet Earth is about 4.5 billion years old.

Warm Neptunes are thought to have either rocky or liquid cores, surrounded by gas. If helium is indeed the dominant component in their atmospheres, the planets would appear white or gray. By contrast, the Neptune of our own solar system is a brilliant azure blue. The methane in its atmosphere absorbs the color red, giving Neptune its blue hue.

This diagram illustrates how hypothetical helium atmospheres might form. These would be on planets about the mass of Neptune, or smaller, which orbit tightly to their stars, whipping around in just days. They are thought to have cores of water or rock, surrounded by thick atmospheres of gas. Radiation from their nearby stars would boil off hydrogen and helium, but because hydrogen is lighter, more hydrogen would escape. It's also possible that planetary bodies, such as asteroids, could impact the planet, sending hydrogen out into space. Over time, the atmospheres would become enriched in helium.

Image credit: NASA/JPL-Caltech

With less hydrogen in the planets' atmospheres, the concentration of methane and water would go down. Both water and methane consist in part of hydrogen. Eventually, billions of years later (a "Gyr" equals one billion years), the abundances of the water and methane would be greatly reduced. Since hydrogen would not be abundant, the carbon would be forced to pair with oxygen, forming carbon monoxide.

A lack of methane in one particular warm Neptune, called GJ 436b, is in fact what led Hu and his team to develop their helium planet theory. Spitzer had previously observed GJ 436b, located 33 light-years away, and found evidence for carbon but not methane. This was puzzling to scientists, because methane molecules are made of one carbon and four hydrogen atoms, and planets like this are expected to have a lot of hydrogen. Why wasn't the hydrogen linking up with carbon to produce methane?

According to the new study, the hydrogen might have been slow-cooked off the planet by radiation from the host stars. With less hydrogen around, the carbon would pair up with oxygen to make carbon monoxide. In fact, Spitzer found evidence for a predominance of carbon monoxide in the atmosphere of GJ 436b.

The next step to test this theory is to look at other warm Neptunes for signs of carbon monoxide and carbon dioxide, which are indicators of helium atmospheres. The team says this might be possible with the help of NASA's Hubble Space Telescope, and NASA's upcoming James Webb Space Telescope may one day directly detect that helium.

Meanwhile, the wacky world of exoplanets continues to surprise astronomers.

"Any planet one can imagine probably exists, out there, somewhere, as long as it fits within the laws of physics and chemistry," said co-author Sara Seager of the Massachusetts Institute of Technology in Cambridge and JPL. "Planets are so incredibly diverse in their masses, sizes and orbits that we expect this to extend to exoplanet atmospheres."

A third author of the paper is Yuk Yung of the California Institute of Technology in Pasadena and JPL.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.


Contacts and sources:
Whitney Clavin 
Jet Propulsion Laboratory

Can Planets Be Rejuvenated Around Dead Stars?

For a planet, this would be like a day at the spa. After years of growing old, a massive planet could, in theory, brighten up with a radiant, youthful glow. Rejuvenated planets, as they are nicknamed, are only hypothetical. But new research from NASA's Spitzer Space Telescope has identified one such candidate, seemingly looking billions of years younger than its actual age.

"When planets are young, they still glow with infrared light from their formation," said Michael Jura of UCLA, coauthor of a new paper on the results in the June 10 issue of the Astrophysical Journal Letters. "But as they get older and cooler, you can't see them anymore. Rejuvenated planets would be visible again."

This artist's concept shows a hypothetical "rejuvenated" planet -- a gas giant that has reclaimed its youthful infrared glow. NASA's Spitzer Space Telescope found tentative evidence for one such planet around a dead star, or white dwarf, called PG 0010+280 (depicted as white dot in illustration).
Credits: NASA/JPL-Caltech

How might a planet reclaim the essence of its youth? Years ago, astronomers predicted that some massive, Jupiter-like planets might accumulate mass from their dying stars. As stars like our sun age, they puff up into red giants and then gradually lose about half or more of their mass, shrinking into skeletons of stars, called white dwarfs. The dying stars blow winds of material outward that could fall onto giant planets that might be orbiting in the outer reaches of the star system.

Thus, a giant planet might swell in mass, and heat up due to friction felt by the falling material. This older planet, having cooled off over billions of years, would once again radiate a warm, infrared glow.

The new study describes a dead star, or white dwarf, called PG 0010+280. An undergraduate student on the project, Blake Pantoja, then at UCLA, serendipitously discovered unexpected infrared light around this star while searching through data from NASA's Wide-field Infrared Survey Explorer, or WISE. Follow-up research led them to Spitzer observations of the star, taken back in 2006, which also showed the excess of infrared light.

At first, the team thought the extra infrared light was probably coming from a disk of material around the white dwarf. In the last decade or so, more and more disks around these dead stars have been discovered -- around 40 so far. The disks are thought to have formed when asteroids wandered too close to the white dwarfs, becoming chewed up by the white dwarfs' intense, shearing gravitational forces.

Other evidence for white dwarfs shredding asteroids comes from observations of the elements in white dwarfs. White dwarfs should contain only hydrogen and helium in their atmospheres, but researchers have found signs of heavier elements -- such as oxygen, magnesium, silicon and iron -- in about 100 systems to date. The elements are thought to be leftover bits of crushed asteroids, polluting the white dwarf atmospheres.

But the Spitzer data for the white dwarf PG 0010+280 did not fit well with models for asteroid disks, leading the team to look at other possibilities. Perhaps the infrared light is coming from a companion small "failed" star, called a brown dwarf -- or more intriguingly, from a rejuvenated planet.

"I find the most exciting part of this research is that this infrared excess could potentially come from a giant planet, though we need more work to prove it," said Siyi Xu of UCLA and the European Southern Observatory in Germany. "If confirmed, it would directly tell us that some planets can survive the red giant stage of stars and be present around white dwarfs."

In the future, NASA's upcoming James Webb Space Telescope could possibly help distinguish between a glowing disk or a planet around the dead star, solving the mystery. But for now, the search for rejuvenated planets -- much like humanity's own quest for a fountain of youth -- endures.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.



Contacts and sources: 
Whitney Clavin
Jet Propulsion Laboratory

Super-Earth Found in Nearby Solar System, Only 21 Light Years Away

Using NASA's Spitzer Space Telescope, astronomers have confirmed the discovery of the nearest rocky planet outside our solar system, larger than Earth and a potential gold mine of science data.

Dubbed HD 219134b, this exoplanet, which orbits too close to its star to sustain life, is a mere 21 light-years away. While the planet itself can't be seen directly, even by telescopes, the star it orbits is visible to the naked eye in dark skies in the Cassiopeia constellation, near the North Star.

This artist's concept shows the silhouette of a rocky planet, dubbed HD 219134b. At 21 light-years away, the planet is the closest outside of our solar system that can be seen crossing, or transiting, its star.
Credits: NASA/JPL-Caltech

HD 219134b is also the closest exoplanet to Earth to be detected transiting, or crossing in front of, its star and, therefore, perfect for extensive research.

"Transiting exoplanets are worth their weight in gold because they can be extensively characterized," said Michael Werner, the project scientist for the Spitzer mission at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "This exoplanet will be one of the most studied for decades to come."

The planet, initially discovered using HARPS-North instrument on the Italian 3.6-meter Galileo National Telescope in the Canary Islands, is the subject of a study accepted for publication in the journal Astronomy & Astrophysics.

Study lead author Ati Motalebi of the Geneva Observatory in Switzerland said she believes the planet is the ideal target for NASA’s James Webb Space Telescope in 2018.

"Webb and future large, ground-based observatories are sure to point at it and examine it in detail,” Motalebi said.

Only a small fraction of exoplanets can be detected transiting their stars due to their relative orientation to Earth. When the orientation is just right, the planet’s orbit places it between its star and Earth, dimming the detectable light of its star. It’s this dimming of the star that is actually captured by observatories such as Spitzer, and can reveal not only the size of the planet but also clues about its composition.

"Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor," said astronomer and study co-author Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. For reference, the closest known planet is GJ674b at 14.8 light-years away; its composition is unknown.

HD 219134b was first sighted by the HARPS-North instrument and a method called the radial velocity technique, in which a planet's mass and orbit can be measured by the tug it exerts on its host star. The planet was determined to have a mass 4.5 times that of Earth, and a speedy three-day orbit around its star.

Spitzer followed up on the finding, discovering the planet transits its star. Infrared measurements from Spitzer revealed the planet's size, about 1.6 times that of Earth. Combining the size and mass gives it a density of 3.5 ounces per cubic inch (six grams per cubic centimeter) -- confirming HD 219134b is a rocky planet.

Now that astronomers know HD 219134b transits its star, scientists will be scrambling to observe it from the ground and space. The goal is to tease chemical information out of the dimming starlight as the planet passes before it. If the planet has an atmosphere, chemicals in it can imprint patterns in the observed starlight.

Rocky planets such as this one, with bigger-than-Earth proportions, belong to a growing class of planets termed super-Earths.

"Thanks to NASA's Kepler mission, we know super-Earths are ubiquitous in our galaxy, but we still know very little about them," said co-author Michael Gillon of the University of Liege in Belgium, lead scientist for the Spitzer detection of the transit. "Now we have a local specimen to study in greater detail. It can be considered a kind of Rosetta Stone for the study of super-Earths."

Further observations with HARPS-North also revealed three more planets in the same star system, farther than HD 219134b. Two are relatively small and not too far from the star. Small, tightly packed multi-planet systems are completely different from our own solar system, but, like super-Earths, are being found in increasing numbers.

JPL manages the Spitzer mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology (Caltech) in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company in Littleton, Colorado. Data are archived at the Infrared Science Archive, housed at Caltech’s Infrared Processing and Analysis Center. 


Contacts and sources:
Whitney Clavin
Jet Propulsion Laboratory