The tell-tale signature of the molecule methane in the atmosphere of the Jupiter-sized extrasolar planet HD 189733b has been found with the Hubble Space Telescope. Under the right circumstances methane can play a key role in prebiotic chemistry -- the chemical reactions considered necessary to form life as we know it. Although methane has been detected on most of the planets in our Solar System, this is the first time any organic molecule has been detected on a world orbiting another star.

 

This discovery proves that Hubble and upcoming space missions, such as the NASA/ESA/CSA James Webb Space Telescope, can detect organic molecules on planets around other stars by using spectroscopy, which splits light into its components to reveal the "fingerprints" of various chemicals.

"This is a crucial stepping stone to eventually characterising prebiotic molecules on planets where life could exist", said Mark Swain of NASA's Jet Propulsion Laboratory (JPL), Pasadena, USA, who led the team that made the discovery. Swain is lead author of a paper in the 20 March issue of Nature.

The discovery comes after extensive observations made in May 2007 with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS). It also confirms the existence of water molecules in the planet's atmosphere, a discovery made originally by NASA's Spitzer Space Telescope in 2007. "With this observation there is no question whether there is water or not -- water is present", said Swain.

The planet, HD 189733b, now known to have methane and water vapour is located 63 light-years away in the constellation Vulpecula, the little fox. HD 189733b, a "hot Jupiter"-type extrasolar planet, is so close to its parent star that it takes just over two days to complete an orbit. "Hot Jupiters" are the size of Jupiter but orbit closer to their stars than the tiny innermost planet Mercury in our Solar System. HD 189733b's atmosphere swelters at 900 degrees C, about the same temperature as the melting point of silver.

The observations were made as the planet HD 189733b passed in front of its parent star in what astronomers call a transit. As the light from the star passed briefly through the atmosphere along the edge of the planet, the gases in the atmosphere imprinted their unique signatures on the starlight from the star HD 189733. According to co-author Giovanna Tinetti from the University College London and the European Space Agency: "Water alone could not explain all the spectral features observed. The additional contribution of methane is necessary to fit the Hubble data".

Methane, composed of carbon and hydrogen, is one of the main components of natural gas, a petroleum product. On Earth, methane is produced by a variety of sources: natural sources such as termites, the oceans and wetland environments, but also from livestock and manmade sources like waste landfills and as a by-product of energy generation. Tinetti is however quick to rule out any biological origin of the methane found on HD 189733b. "The planet's atmosphere is far too hot for even the hardiest life to survive -- at least the kind of life we know from Earth. It's highly unlikely that cows could survive here!"

The astronomers were surprised to find that the planet has more methane than predicted by conventional models for "hot Jupiters". This type of hot planet should have much more carbon monoxide than methane but HD 189733b doesn't. Tinetti explains: "A sensible explanation is that the Hubble observations were more sensitive to the dark night side of this planet where the atmosphere is slightly colder and the photochemical mechanisms responsible for methane destruction are less efficient than on the day side".

Though the star-hugger planet is too hot for life as we know it, "this observation is proof that spectroscopy can eventually be done on a cooler and potentially habitable Earth-sized planet orbiting a dimmer red dwarf-type star", Swain said. The ultimate goal of studies like these is to identify prebiotic molecules in the atmospheres of planets in the "habitable zones" around other stars, where temperatures are right for water to remain liquid rather than freeze or evaporate away.

"These measurements are an important step to our ultimate goal of determining the conditions, such as temperature, pressure, winds, clouds, etc., and the chemistry on planets where life could exist. Infrared spectroscopy is really the key to these studies because it is best matched to detecting molecules", said Swain.

 

From:http://www.sciencedaily.com/releases/2008/03/080319140759.htm

 

Researchers at the National Institute of Standards and Technology (NIST) and the Joint Quantum Institute (NIST/University of Maryland) have developed a new method for creating pairs of entangled photons, particles of light whose properties are interlinked in a very unusual way dictated by the rules of quantum physics. The researchers used the photons to test fundamental concepts in quantum theory.

 

In the experiment, the researchers send a pulse of light into both ends of a twisted loop of optical fiber. Pairs of photons of the same color traveling in either direction will, every so often, interact in a process known as "four-wave mixing," converting into two new, entangled photons, one that is redder and the other that is bluer than the originals.

Although the fiber's twist means that pairs emerging from one end are vertically polarized (having electric fields that vibrate up and down) while pairs from the other end are horizontally polarized (vibrating side to side), the setup makes it impossible to determine which path the newly created photon pairs took. Since the paths are indistinguishable, the weird rules of quantum physics say that the photon pairs actually will be in both states--horizontal and vertical polarization--at the same time. Until someone measures one, at which time both photons must chose one specific, and identical, state.

This "spooky action at a distance" is what caused Einstein to consider quantum mechanics to be incomplete, prompting debate for the past 73 years over the concepts of "locality" and "realism." Decades of experiments have demonstrated that measurements on pairs of entangled particles don't agree with the predictions made by "local realism," the concept that processes occurring at one place have no immediate effect on processes at another place (locality) and that the particles have definite, preexisting properties (called "hidden variables") even without being measured (realism).

Experiments so far have ruled out locality and realism as a combination. But could a theory assuming only one of them be correct" Nonlocal hidden variables (NLHV) theories would allow for the possibility of hidden variables but would concede nonlocality, the idea that a measurement on a particle at one location may have an immediate effect on a particle at a separate location.

Measuring the polarizations of the pairs of entangled particles in their setup, the researchers showed that the results did not agree with the predictions of certain NLHV theories but did agree with the predictions of quantum mechanics. In this way, they were able to rule out certain NLHV theories. Their results agree with other groups that have performed similar experiments.

* J. Fan, M.D. Eisaman and A. Migdall, Bright phase-stable broadband fiber-based source of polarization-entangled photon pairs. Physical Review A 76, 043836 (2007). 

** M.D. Eisaman, E.A. Goldschmidt, J. Chen, J. Fan and A. Migdall. Experimental test of non-local realism using a fiber-based source of polarization-entangled photon pairs. Physical Review A., upcoming.

 

From:http://www.sciencedaily.com/releases/2008/03/080318174941.htm

 

The UK’s national computing grid, along with their counterparts in the US (TeraGrid) and Europe have helped UCL (University College London) scientists shed light on how life on earth may have originated.

 

Deep ocean hydrothermal vents have long been suggested as possible sources of biological molecules such as RNA and DNA but it was unclear how they could survive the high temperatures and pressures that occur round these vents.

Professor Peter Coveney and colleagues at the UCL Centre for Computational Science have used computer simulation to provide insight into the structure and stability of DNA while inserted into layered minerals. Computer simulation techniques have rarely been used to understand the possible chemical pathways to the formation of early biomolecules until now.

Professor Coveney explains, “Computational grids are only now being made easy to use for scientists, enabling simulations of sufficient size to model these large biomolecule and mineral systems”.

Previous experimental studies have shown that molecules such as DNA can be inserted into minerals called layered double hydroxides (LDHs) but no one has thus far been able to show at the level of atoms and molecules how the DNA interacts with the mineral, or how the DNA might look inside the mineral layers. These minerals would have been common in the earliest age of Earth 2500 million years ago.

The simulations reproduced the high temperatures and pressures that occur around hydrothermal vents. It was shown that the structure of DNA inserted into layered minerals becomes stabilized at these conditions and therefore protected from catalytic and thermal degradation.

“Grids of supercomputers are essential for this kind of study”, says Professor Coveney, “The time taken to run these simulations is reduced from the years that a desktop computer would take, to hours by using the many thousands of processors made available across continents”.

Professor Coveney’s group has been researching into the routes to the origin of life for a number of years, studying the way that genetic information may have arisen and been replicated, as well as how small molecules may have formed, working together with colleagues at Nottingham and Durham Universities.

Journal reference: ‘Computer Simulation Study of the Structural Stability and Materials Properties of DNA-Intercalated Layered Double Hydroxides’ by Mary-Ann Thyveetil, Peter Coveney, H. Chris Greenwell and James Suter, is published online in the Journal of the American Chemical Society on Tuesday 18 March 2008.

 

From:http://www.sciencedaily.com/releases/2008/03/080318212430.htm

A team of chemists and physicists at the University of California, San Diego has developed a tiny, inexpensive sensor chip capable of detecting trace amounts of hydrogen peroxide, a chemical used in the most common form of homemade explosives.

 

 

Photo of penny and peroxide sensor The hydrogen peroxide sensor is the size of a penny. (Credit: UCSD)

 

Scientists at the University of Bonn have discovered a new rare type of haemoglobin. Haemoglobin transports oxygen in the red blood corpuscles. When bound to oxygen it changes colour. The new haemoglobin type appears optically to be transporting little oxygen. Measurements of the blood oxygen level therefore present a similar picture to patients suffering from an inherited cardiac defect. After examining two patients, the scientists now understand that the new type of haemoglobin distorts the level of oxygen measured.

 

The scientists have named the type 'Haemoglobin Bonn'. Haemoglobin transports oxygen to the body's cells and in return picks up carbon dioxide there. In doing so it changes colour. With an optical measuring instrument, known as a pulse oximeter, you can therefore measure whether there is enough oxygen present in the blood. The cause of anoxia can be an inherited cardiac defect, for example.

This was also the tentative diagnosis in the case of a four-year-old boy who was admitted to the Paediatric Clinic of the Bonn University Clinic. However, after a thorough examination, the paediatricians Dr. Andreas Hornung and his colleagues did not find any cardiac defect. A low saturation of oxygen had also been previously found in the blood of the boy's 41-year-old father, again without apparent signs of a cardiac defect.

Dr. Berndt Zur from Professor Birgit Stoffel-Wagner's team at the Institute of Clinical Chemistry and Pharmacology examined the boy's and the father's haemoglobin. He eventually realised that they were dealing with a new type of the blood pigment. 'The pulse oximeter is put on a finger as a clip and X-rays it with infrared radiation,' he explains. 'Haemoglobin absorbs infrared light in the absence of oxygen. The lower the content of oxygen in the blood, the less light penetrates the finger and reaches the sensor of the oximeter.' But Haemoglobin Bonn absorbs a bit more infrared light than normal oxygen saturated haemoglobin, even when combined with oxygen. 'That's why, at first, we did not understand why the patients did not have any particular health problems,' Dr. Zur says.

Every human has two main heart ventricles. One pumps the blood through the arteries to the lungs, where the haemoglobin releases the carbon dioxide and takes on oxygen. The other one pumps the blood which is saturated with oxygen from the lungs to every cell in the body. Both ventricles must be separated by a wall in the heart, so that the oxygen-rich blood does not mix with the anoxaemic blood. But some people have a hole in this septum.

In such cases, the pulse oximeter shows anoxia. Doctors therefore see this as a sign of a cardiac defect. Another cause is what is known as the Apnoea Syndrome. In the patients affected, breathing can cease for more than a minute. That is why the father of the 4-year-old received oxygen treatment at nights for some time. 'If we had known about Haemoglobin Bonn before, father and son could have been spared the fear of a cardiac defect or the Sleep Apnoea Syndrome,' Dr. Zur explains.

This research is published in the journal 'Clinical Chemistry'.  (http:www.clinchem.org/cgi/content/full/54/3/594).

 

From:http://www.sciencedaily.com/releases/2008/03/080317102452.htm

 

Venus Express has constantly been observing the south pole of Venus and has found it to be surprisingly fickle. An enormous structure with a central part that looks like the eye of a hurricane, morphs and changes shape within a matter of days, leaving scientists puzzled.

 

The eye of the hurricane is at the centre of a 2000 km-wide vortex. It was discovered in 1974 by the Mariner 10 spacecraft. There is a similar structure on the planet’s north pole, which was observed by the Pioneer Venus mission in 1979.

Venus Express scientists have been studying the structure in the thermal infrared, the wavelength range which reveals the temperature at the cloud-tops. Seen in this wavelength, the core of the vortex appears very bright, probably indicating that a lot of atmospheric gases are moving downward in the region, which creates a depression at the cloud-tops, making the region hotter.  

“Simply put, the enormous vortex is similar to what you might see in your bathtub once you have pulled out the plug” says Giuseppe Piccioni, co-Principal Investigator for the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express, at IASF-INAF, Rome, Italy.

In June 2006, the vortex appeared hourglass-shaped, closely matching observations in the north polar region by Pioneer Venus. Now we know that it changes its shape within a matter of days, from orbit to orbit. The image taken on 26 February 2007 shows the 'classic' dipole shape at the centre of the vortex, similar to that which has been observed previously. But an image taken a mere 24 hours earlier shows the centre of the vortex to be almost circular, indicating that the shape of this feature can change very fast. At other times, it is typically oval.

The vortex is very complex, with atmospheric gases flowing in different directions at different altitudes.

Scientists are not sure what actually creates the vortex. Colin Wilson, at the University of Oxford, says, “One explanation is that atmospheric gases heated by the Sun at the equator, rise and then move poleward. In the polar regions, they converge and sinks again. As the gases moves towards the poles, they are deflected sideways because of the planet’s rotation.”

The dynamic nature of this vortex is similar to behaviour observed in other vortices on Earth, including those observed at the centre of hurricanes.

Investigators will keep a close watch on the polar region and its variability, in order to gain a better understanding of how it works.

 

From: http://www.sciencedaily.com/releases/2008/03/080313095626.htm

 

Envisat captures the break up of the massive A53A iceberg located just east of the South Georgia Island (visible at image bottom) in the southern Atlantic Ocean.

 

A huge fissure was spotted running south to north through the berg on 1 March by C-CORE, the Canadian ice-tracking service, while studying satellite images collected from Envisat’s Advanced Synthetic Aperture Radar (ASAR) instrument using the Polar View monitoring programme.

The radar image indicated the berg was unstable and likely to split. Just days afterwards on 4 March, Envisat's Medium Resolution Imaging Spectrometer (MERIS) sensor captured the break. Both bergs are estimated to measure around 30 km in length. As a reference, South Georgia Island is approximately 180-km long.

The break up of A53A, which calved off the Larsen Ice Shelf in late April 2005, occurred in relatively warm waters, making it highly likely that numerous smaller icebergs and ice islands will calve off the two icebergs.

Several different processes can cause an iceberg to form, or ‘calve’, including deterioration from high temperatures or the sun's radiation, action from winds and waves or a collision with another iceberg.

Since 2006, ESA has supported Polar View, a satellite remote-sensing programme funded through the Global Monitoring for Environment and Security (GMES) Service Element (GSE) that focuses on the Arctic and the Antarctic.

GMES responds to Europe’s needs for geo-spatial information services by bringing together the capacity of Europe to collect and manage data and information on the environment and civil security, for the benefit of European citizens.

ASAR is able to produce high-quality images of icebergs and ice sheets and is capable of differentiating between different types of ice because it is able to see through clouds and local darkness – conditions often found in polar areas.

 

From:http://www.sciencedaily.com/releases/2008/03/080314100420.htm

 

Crop scientists have cloned a gene that controls the shape of tomatoes, a discovery that could help unravel the mystery behind the huge morphological differences among edible fruits and vegetables, as well as provide new insight into mechanisms of plant development.

 

The gene, dubbed SUN, is only the second ever found to play a significant role in the elongated shape of various tomato varieties, said Esther van der Knaap, lead researcher in the study and assistant professor of horticulture and crop science at Ohio State University's Ohio Agricultural Research and Development Center (OARDC) in Wooster.

One of the most diverse vegetable crops in terms of shape and size variations, tomatoes have evolved from a very small, round wild ancestor into the wide array of cultivated varieties -- some large and segmented, some pear-shaped, some oval, some resembling chili peppers -- available through most seed catalogs and for sale in supermarkets. However, very little is known about the genetic basis for such transformations in tomatoes, and virtually nothing has been discerned about morphological changes in other fruits and vegetables.

"Tomatoes are the model in this emerging field of fruit morphology studies," van der Knaap pointed out. "We are trying to understand what kind of genes caused the enormous increase in fruit size and variation in fruit shape as tomatoes were domesticated. Once we know all the genes that were selected during that process, we will be able to piece together how domestication shaped the tomato fruit -- and gain a better understanding of what controls the shape of other very diverse crops, such as peppers, cucumbers and gourds."

One of the first pieces in van der Knaap's fruit-development puzzle is SUN, which takes its name from the "Sun 1642" cultivated variety where it was found -- an oval-shaped, roma-type tomato with a pointy end. The gene also turned out to be very common in elongated heirloom varieties, such as the Poblano pepper-like "Howard German" tomato.

"After looking at the entire collection of tomato germplasm we could find, we noticed that there were some varieties that had very elongated fruit shape," van der Knaap explained. "By genetic analysis, we narrowed down the region of the genome that controls this very elongated fruit shape, and eventually narrowed down that region to a smaller section that we could sequence to find what kind of genes were present at that location.

"In doing that," van der Knaap continued, "we identified one key candidate gene that was turned on at high levels in the tomato varieties carrying the elongated fruit type, while the gene was turned off in round fruit. And after we confirmed that observation in several other varieties, we found that this gene was always very highly expressed in varieties that carry very elongated fruit."

Once SUN was identified, the next step involved proving whether this gene was actually responsible for causing changes in fruit shape. To do so, van der Knaap and her team conducted several plant-transformation experiments. When the SUN gene was introduced into wild, round fruit-bearing tomato plants, they ended up producing extremely elongated fruit. And when the gene was "knocked out" of elongated fruit-bearing plants, they produced round fruit similar to the wild tomatoes.

"SUN doesn't tell us exactly how the fruit-shape phenotype is altered, but what we do know is that turning the gene on is very critical to result in elongated fruit," van der Knaap said. "We can now move forward and ask the question: Does this same gene, or a gene that is closely related in sequence, control fruit morphology in other vegetables and fruit crops?"

Something else van der Knaap and her team found out is that SUN encodes a member of the IQ67 domain of plant proteins, called IQD12, which they determined to be sufficient -- on its own -- to make tomatoes elongated instead of round during the plant transformation experiments.

IQD12 belongs to a family of proteins whose discovery is relatively new in the world of biology. So new that IQD12 is only the second IQ67 protein-containing domain whose function in plants has been identified. The other one is AtIQD1, discovered in the plant model Arabidopsis thaliana, which belongs to the same family as broccoli and cabbage. In Arabidopsis, AtIQD1 increases levels of glucosinolate, a metabolite that Ohio State researchers are studying in broccoli for its possible role in inhibiting cancer (http://researchnews.osu.edu/archive/goodbroc.htm).

"Unlike AtIQD1, SUN doesn't seem to be affecting glucosinolate levels in tomato, since these metabolites are not produced in plants of the Solanaceous family (which includes tomato, peppers, eggplant and other popular crops)," van der Knaap explained. "But there appears to be a common link between the two genes, which is that they may be regulating tryptophan levels in the plant. Thus, SUN may be telling us more about the whole process of diversification in fruits and across plant species, perhaps through its impact on plant hormones and/or secondary metabolites levels."

In the process of identifying and cloning SUN, van der Knaap's team was also able to trace the origin of this gene and the process by which it came to reside in the tomato genome.

Another unique characteristic of the SUN gene is that it affects fruit shape after pollination and fertilization, with the most significant morphological differences found in developing fruit five days after plant flowering. The only other fruit-shape gene previously identified -- OVATE, a discovery by Cornell University plant breeder Steven Tanksley, van der Knaap's advisor while she was a post-doctoral associate there -- influences the future look of a fruit before flowering, early in the ovary development.

The discovery was reported, as the cover article, in the March 14 issue of the journal Science.

Co-authors in the Science paper include Eric Stockinger, associate professor of horticulture and crop science at OARDC; Han Xiao, a postdoctoral researcher in horticulture and crop science at Ohio State; Ning Jiang, assistant professor of horticulture at Michigan State University; and Erin Schaffner, a former undergraduate student from the College of Wooster who conducted her independent study in van der Knaap's lab.

Funding for this research came from the National Science Foundation (NSF).

 

From:http://www.sciencedaily.com/releases/2008/03/080313143057.htm

 

The house where Rome's first emperor lived in before he was crowned has opened this week to the public for the first time since it was discovered nearly half a century ago.

MATTERS OF SCALE. A phytoplankton bloom (lighter turquoise waters) in the Bering Sea offshore of the Aleutian Islands is visible in this July 1998 satellite image. Relatively small changes in ocean chemistry may have big effects on such small creatures. Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)/NASA/GSFC, GeoEye

CRUNCH. About the size of a peppercorn, a Limacina helicina pteropod is a favorite snack of larger creatures. Declining seawater pH could hamper formation of pteropod shells. Hofmann

LOSERS AND WINNERS. More acidic waters could be tough on the tiny coccolithophore Emiliania huxleyi (left), which builds a shell of calcium-carbonate platelets; but comfy for nitrogen-fixing cyanobacteria such as Trichodesmium (right). Björn Rost; David Caron/Univ. of Southern California