Study: Diet Changes May Have Been Crucial Step in Becoming Human

Posted June 25th, 2013 at 7:27 pm (UTC+0)
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Artist Illustration of Paranthropus hominid in southern Africa 1 million years ago. (Artwork by Walter Voigt -provided by Lee Berger and Brett Hilton-Barber)

Illustration of Paranthropus hominid in southern Africa one million years ago. (Artwork by Walter Voigt -provided by Lee Berger and Brett Hilton-Barber)

A change in  diet about 3.5 million years ago  may have  set hominid species on a path to becoming  human, according to a study led by the University of Colorado, Boulder.

Scientists conducted high-tech tests on the tooth enamel found in  remains of ancient hominid species. The results indicated that, prior to that dietary change, the hominids ate pretty much like chimpanzees, dining on items like fruits and some leaves.

But then some hominid species started adding  grasses and flowering plants to their daily menus.

Grasses and sedges were readily available back then, but the hominids seem to have ignored them for an extended period, said anthropology Professor Matt Sponheimer, lead author of the study.

“We don’t know exactly what happened,” said Sponheimer. “But we do know that after about 3.5 million years ago, some of these hominids started to eat things that they did not eat before, and it is quite possible that these changes in diet were an important step in becoming human.”

A field of grass-like sedge in Hamerkop Kloof, Magaliesberg, South Africa (Wikimedia Commons)

A field of grass-like sedge in Hamerkop Kloof, Magaliesberg, South Africa (Wikimedia Commons)

Scientists had previously analyzed the teeth of  about 87 ancient hominid specimens.  Sponheimer and his team came up with new detailed information on the teeth of 88 additional specimens, which also included five previously unanalyzed hominid species.

To find out what kind of plants these early hominids ate, Sponheimer’s team analyzed the carbon isotopes found on the fossilized teeth.  The researchers found the carbon signals of two distinct plant groups; the first, called C3, came from plants like trees and bushes, while the other,  called C4, came from plants like grasses and sedges, which are flowering grasses.

The researchers also examined the microscopic wear of hominid teeth, which provided scientists with more information on the foods they were eating. Since there were multiple species of hominids, there was no such thing as one specific hominid diet.

The skull of Paranthropus boisei photographed at the Nairobi National Museum (Bjørn Christian Tørrissen via Wikimedia Commons))

The skull of Paranthropus boisei photographed at the Nairobi National Museum (Bjørn Christian Tørrissen via Wikimedia Commons)

While early ancestors in the genus Homo, which includes modern humans and the 3 million-year-old fossil known as Lucy – who many scientists see as the matriarch of today’s humans – were diversifying their diets with different food choices, another type of short, upright hominid, the Paranthropus boisei, who also lived in Eastern Africa at the time, was moving toward a much more specific diet made up mostly of items like the grasses.

Scientists had given the P. boisei hominids the nickname “Nutcracker Man” because it had large, flat teeth and powerful jaws that may have been powerful enough to crack nuts.  But, according to Sponheimer, more recent analyses suggest  they might have actually used their back teeth to grind grasses and sedges.

“We now have the first direct evidence that, as the cheek teeth on hominids got bigger, their consumption of plants like grasses and sedges increased,” he said. “We also see niche differentiation between Homo and Paranthropus. It looks probable that Paranthropus boisei had a relatively restricted diet, while members of the genus Homo were eating a wider variety of things. The genus Paranthropus went extinct about one million years ago, while the genus Homo, that includes us, obviously did not.”

Researchers are  puzzled at the differences in the evolution of those hominids living in eastern Africa compared to those from southern Africa.

Another hominid, called Paranthropus robustus, which was found in southern Africa was very anatomically similar its eastern African cousin, P. boisei.  But Sponheimer and his team found that the teeth of the two had quite different carbon isotopic compositions in their teeth, which suggested that they each ate different diets.

Another artist representation of Paranthropus in southern Africa more than 1 million years ago. (Courtesy ArchaeologyInfo.com/ScottBjelland)

Artist representation of Paranthropus in southern Africa more than one million years ago. (Courtesy ArchaeologyInfo.com/ScottBjelland)

The southern African P. robustus hominid appeared to have augmented its diet of grasses and sedges with items from the C3 group such as trees and bushes.

“This has probably been one of the biggest surprises to us so far,” said Sponheimer. “We had generally assumed that the Paranthropus species were just variants on the same ecological theme, and that their diets would probably not differ more than those of two closely related monkeys in the same forest.

But the researchers found that their isotopic evidence of each of the hominids indicated that their diets were so different from each other that they could have been as different as primate diets can be.

“Ancient fossils don’t always reveal what we think they will. The upside of this disconnect is that it can teach us a great deal, including the need for caution in making pronouncements about the diets of long-dead critters,” said Sponheimer.

Science Images of the Week

Posted June 21st, 2013 at 7:33 pm (UTC+0)
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NASA, this week, released a spectacular 1.3 billion pixel image that was taken by the Curiosity Mars Rover.  It shows Curiosity at the "Rocknest" site where the rover scooped up samples of windblown dust and sand.  While this is a reduced version of an original panorama you can find the full version complete with pan and zoom controls by clicking on the photo.  (NASA/JPL-Caltech/MSSS)

NASA’s spectacular 1.3 billion pixel image, taken by the Curiosity Mars Rover, shows Curiosity at the Rocknest site, where it scooped up samples of windblown dust and sand. This is a reduced version of the original panorama. Click on photo to see full version. (NASA)

Three mouse lemurs (Microcebus murinus) peer cautiously from their nesting tube at the sound of an approaching technician who might just be carrying snacks.  Researchers from the Duke Lemur Center recently conducted personality research that found some of mouse lemurs are shy, while others were actually bold. (David Haring, Duke Lemur Center)

Three mouse lemurs (Microcebus murinus) peer cautiously from their nesting tube. Personality research from the Duke Lemur Center found some mouse lemurs are shy, while others were actually bold. (David Haring, Duke Lemur Center)

Scientists at France’s Ecole Polytechnique Fédérale de Lausanne designed and built a robotic ‘cheetah-cub’ that runs like a cat. During tests, it demonstrated an ability to run fast and steady at nearly seven times its body length in one second. While it’s not as agile as a real cat, the French scientists say it still has excellent auto-stabilization characteristics (© EPFL)

Scientists at the Switzerland’s Ecole Polytechnique Fédérale de Lausanne designed and built a robotic cheetah cub that runs like a cat. During tests, the device demonstrated an ability to run fast and steady at nearly seven times its body length in one second. (© EPFL)

A team of researchers from the University of Miami was recently doing some filming at Dean’s Blue Hole in the Bahamas.  It’s the world's deepest known blue hole or underwater sinkhole that drops to a depth of 202 meters.  (Patrick Rynne)

University of Miami researchers film at Dean’s Blue Hole in the Bahamas, the world’s deepest known blue hole or underwater sinkhole that drops to a depth of 202 meters. (Patrick Rynne)

We all how know just how industrious an ant can be. Here’s one carrying a wild chili pepper seed.  (Thomas Carlo)

Scientists from the University of Washington, studying in South America, have found that seeds of the wild chili pepper have a better chance of surviving and becoming a new plant if first swallowed and then expelled by a bird. Here’s an ant carrying a wild chili pepper seed that made its trip by and through a bird. (Thomas Carlo)

The Sculptor galaxy located in the constellation Sculptor is seen here in a new composite image from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Southern Observatory in Chile. (NASA/JPL-Caltech/JHU)

The Sculptor galaxy, located in the constellation Sculptor, is seen in a new composite image from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Southern Observatory in Chile. (NASA)

Usually particle accelerators such as CERN’s Large Hadron Collider are quite large in size – the LHC is contained within a tunnel 27 kilometers in circumference.  But, scientists at the University of Texas at Austin recently built one that can sit on a tabletop.  (Rafal Zgadzaj)

Scientists at the University of Texas at Austin recently built a particle accelerator that can sit on a tabletop. Most particle accelerators, such as CERN’s Large Hadron Collider (LHC), are massive. The LHC is contained within a tunnel that is 27 kilometers in circumference. (Rafal Zgadzaj)

This is a living brain neuron in culture. A team of scientists from the University of Southern California has developed a way to see where and how memories are made by engineering microscopic probes that light up synapses in a living neuron in real time by attaching fluorescent markers onto synaptic proteins – all without affecting the neuron's ability to function.  (Don Arnold)

This is a living brain neuron in culture. Scientists from the University of Southern California have developed a way to see where and how memories are made by engineering microscopic probes that light up synapses in a living neuron in real time by attaching fluorescent markers onto synaptic proteins – all without affecting the neuron’s ability to function. (Don Arnold)

Could this little guy be in your salad?  A cabbage looper caterpillar makes it way through some spinach and carrots.  (Se Kim/Rice University)

Rice University scientists are conducting research to determine if produce such as spinach and carrots can be encouraged to product more cancer-fighting antioxidants by controlling its circadian cycle with light. Here, a cabbage looper caterpillar makes its way through some of vegetable that were being studied. (Se Kim/Rice University)

Scientists are getting ready to launch a rocket from NASA's Wallops Flight Facility in Virginia for a five-minute trip to study a global electrical current called the dynamo that sweeps through the ionosphere.  A chemical trail like the one here will help researchers track wind movement to determine how it affects the movement of charged particles in the atmosphere.  (NASA)

Scientists are getting ready to launch a rocket from NASA’s Wallops Flight Facility in Virginia. The five-minute trip will be to study a global electrical current called the dynamo that sweeps through the ionosphere. A chemical trail, like the one here, will help researchers track wind movement to determine how it affects the movement of charged particles in the atmosphere. (NASA)

US, Europe Could Collide to Form Supercontinent

Posted June 18th, 2013 at 7:14 pm (UTC+0)
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North America and Europe are now separated by the Atlantic Ocean.  Geologists have found clues that may signal the beginning of a cycle where the Atlantic will disappear and the Continents will collide and form a new supercontinent. (Map: Google)

North America and Europe are now separated by the Atlantic Ocean. Geologists have found clues that may signal the beginning of a cycle where the Atlantic will disappear and the continents will collide and form a new supercontinent. (Map: Google)

Taking a trip from the United States to Europe might be much easier in 220 million years, according to a recent study, which suggests that’s when the Atlantic Ocean could close up, causing North America to collide with Europe.

Australian geologists have detected a new subduction zone–when two oceanic plates collide–forming off the coast of Portugal. It’s the first evidence this previously passive margin in the Atlantic Ocean is now becoming active.

Subduction zones, such as the newly discovered one forming near Iberia, form when one of the dozens of tectonic plates that cover our planet dives and ducks beneath another plate, into the layer located just beneath the surface (the mantle) as the two plates converge.

Illustration of the Wlson Cycle (Used with Permission - Lynn S. Fichter © 1999)

Illustration of the Wlson Cycle (Used with Permission – Lynn S. Fichter © 1999)

After mapping the ocean floor, the research team found the surface was beginning to fracture, which indicates tectonic activity around the South West Iberia plate margin.

“What we have detected is the very beginnings of an active margin. It’s like an embryonic subduction zone,” said Dr. João Duarte, from Monash University, the study’s lead scientist. “Significant earthquake activity, including the 1755 quake which devastated Lisbon, indicated that there might be convergent tectonic movement in the area. For the first time, we have been able to provide not only evidences that this is indeed the case, but also a consistent driving mechanism.”

The study indicates the subduction zone beginning to form off Portugal’s coast could signal that a new phase of the Wilson Cycle has started.  The Wilson Cycle, named for the late Canadian geologist, John Tuzo Wilson, is the periodic opening and closing of the world’s ocean basins, caused by tectonic plate movement.

This cycle is responsible for the joining of continents into supercontinents, which then stabilize and subsequently break up again into individual continents.

Supercontinent Pangaea forms and breaks apart

Supercontinent Pangaea forms and breaks apart

Over the known history of our planet, a number of these supercontinents have formed and broken up. Pangaea, one of the most famous of these,  formed more than 300 million years ago, eventually breaking apart, around 200 million years ago, into the seven continents we’re familiar with today.

The researchers’ findings give other scientists a unique opportunity to observe as a passive margin–the edge of a continental plate that experiences very little tectonic activitybecomes an active margin, which occurs when there is increased tectonic activity because a continental plate is crashing into a nearby oceanic plate, a geological process that takes about 20 million years. Even at this early phase of the process, the new-found subduction zone should provide data that is crucial to refining geodynamic models.

“Understanding these processes will certainly provide new insights on how subduction zones may have initiated in the past and how oceans start to close,” Duarte said.

Scientists Discover How Marine Mammals Hold Their Breath for Long Periods

Posted June 14th, 2013 at 6:04 pm (UTC+0)
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An otter swims underwater the Detroit, Michigan Zoo (Ellen Meiselman via Flickr/Creative Commons)

An otter swims underwater the Detroit, Michigan Zoo (Ellen Meiselman via Flickr/Creative Commons)

Special properties of an oxygen-binding protein in the muscles of marine mammals, such as seals, whales and dolphins, are the reason these animals can hold their breath underwater for long periods of time, according to a new study.

Many of these mammalian divers can hold their breath underwater for over an hour, while land-based mammals, such as humans, can only do so for a few minutes at most.

Scientists from the University of Liverpool, who led the study, were able to identify a unique molecular characteristic of myoglobin, an iron and oxygen-binding protein found in sperm whales and other diving mammals. Until this finding, very little was known about how the molecule is adapted in the diving marine mammals.

The researchers,  in collaboration with the University of Manitoba and University of Alaska, found a high concentration of myoglobin, the substance that makes meat look red, in the muscles of the mammalian divers. In fact, the amount was so high in the muscle that it almost looked black in color.

Monachus schauinslandi (Hawaiian Monk Seal) underwater at Five Fathom Pinnacle, Hawaii. (Kent Backman via Wikimedia Commons)

Monachus schauinslandi (Hawaiian Monk Seal) underwater at Five Fathom Pinnacle, Hawaii. (Kent Backman via Wikimedia Commons)

This discovery allowed the scientists to trace the evolution of how the muscles of more than 100 species of mammals, including fossil remains of their ancient predecessors, were able to store oxygen.

“We studied the electrical charge on the surface of myoglobin and found that it increased in mammals that can dive underwater for long periods of time,” said Dr. Michael Berenbrink,  from the University of Liverpool, who led the international team of scientists. “We were surprised when we saw the same molecular signature in whales and seals, but also in semi-aquatic beavers, muskrats and even water shrews.”

Mapping the unique molecular signature of myoglobin throughout the mammalian family tree allowed scientists to recreate the muscle oxygen stores found in the extinct ancestors of today’s diving mammals.  The team then was able to find the first evidence of a common amphibious forefather of modern sea cows, hyraxes and elephants that lived 65 million years ago in shallow African waters.

While marine mammals like seals, dolphins and whales can stay underwater for long periods of time, humans can only do so for about a minute. (gadgetboy32 via Flickr/Creative Commons)

While marine mammals like seals, dolphins and whales can stay underwater for long periods of time, humans can only do so for about a minute or so. (gadgetboy32 via Flickr/Creative Commons)

“Our study suggests that the increased electrical charge of myoglobin in mammals that have high concentrations of this protein causes electro-repulsion, like similar poles of two magnets,” said Dr. Scott Mirceta, a member of the research team. “This should prevent the proteins from sticking together and allow much higher concentrations of the oxygen-storing myoglobin in the muscles of these divers.”

The researchers’ studies could provide insight into a number of human diseases such as Alzheimer’s and diabetes, while also assisting in the development of artificial blood substitutes.

“This finding illustrates the strength of combining molecular, physiological and evolutionary approaches to biological problems and, for the first time, allows us to put ‘flesh’ onto the bones of these long extinct divers,” said Berenbrink.

Watch a video on this discovery (University of Liverpool/BBSRC)

Simple Theory May Explain Dark Matter

Posted June 11th, 2013 at 5:54 pm (UTC+0)
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An artist's impression shows the Milky Way galaxy. The blue halo of material surrounding the galaxy indicates the expected distribution of the mysterious dark matter. (ESO/Calçada)

Artist’s impression of the Milky Way galaxy. The blue halo of material surrounding the galaxy indicates the expected distribution of dark matter. (ESO/Calçada)

Scientists at Vanderbilt University believe dark matter, an invisible substance that makes up almost 85 percent of our universe, might be made out of particles that have an unusual, donut-shaped electromagnetic field called an anapole.

A number of theories concerning dark matter have been developed over the years, but the Vanderbilt University scientists have come up with a relatively simple theory to explain what has so far been unexplainable.

Top image: Comparison of an anapole field in red with common electric and magnetic dipole field, blue. Middle & Bottom: Anapole field - red and Dipole field - blue (Michael Smeltzer, Vanderbilt University)

Top image: Comparison of an anapole field in red with common electric and magnetic dipole field, blue. Middle & Bottom: Anapole field – red and Dipole field – blue (Michael Smeltzer, Vanderbilt University)

In a paper entitled Anapole Dark Matter, they suggest dark matter particles are surrounded by a rare form of electromagnetism.

“There are a great many different theories about the nature of dark matter. What I like about this theory is its simplicity, uniqueness, and the fact that it can be tested,” said Professor Robert Scherrer, a theoretical physicist at Vanderbilt University who performed a detailed analysis along with post-doctoral fellow Chiu Man Ho.

The two physicists believe dark matter might be made out of a type of elementary electrically neutral particle called the Majorana fermion (or Majorana Particle). The existence of this particle was predicted by Italian physicist Ettore Majorana in 1937, but has so far escaped detection.

Fermions – predicted by Paul Dirac in 1928 and named after the renowned physicist Enrico Fermi – are thought to be basic particles that scientists consider to be the building blocks of matter.  Some scientists think the Marjorana fermion may be a neutrino, but they haven’t been able determine the basic nature of this unique and mysterious particle.

While a number of physicists have also previously suggested that dark matter is composed of Majorana particles, Scherrer and Ho performed detailed calculations they believe prove the particles are uniquely suitable to have a rare, donut-shaped type of electromagnetic field called an anapole.

Ettore Majorana - Circa 1906. The Marjoran fermion or particle was predicted by him in 1937, but so far has escaped detection. (Wikimedia Commons)

Ettore Majorana – Circa 1906. The Marjoran fermion or particle was predicted by him in 1937, but so far has escaped detection. (Wikimedia Commons)

The Majorana fermions are difficult to detect, according to Scherrer and Ho, because this anapole field gives the particles certain properties that make them quite different from others that have more common fields comprised of two poles – north and south, positive and negative.

“Most models for dark matter assume that it interacts through exotic forces that we do not encounter in everyday life,” said Scherrer. “Anapole dark matter makes use of ordinary electromagnetism that you learned about in school: the same force that makes magnets stick to your refrigerator or makes a balloon rubbed on your hair stick to the ceiling. Further, the model makes very specific predictions about the rate at which it should show up in the vast dark matter detectors that are buried underground all over the world. These predictions show that soon the existence of anapole dark matter should either be discovered or ruled out by these experiments.”

Scientists developed the concept of dark matter in the 1930s, while trying to explain discrepancies in the rotational rate of galactic clusters. Since then, astronomers have also found similar inconsistencies in the rate at which stars rotate around individual galaxies. Assuming they contain a large amount of invisible dark matter is the most straightforward way to explain these discrepancies.

NASA Builds Bridge to Future with LEGOs

Posted June 7th, 2013 at 5:30 pm (UTC+0)
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The LEGO Group recently unveiled the world’s largest LEGO model, a 1:1 replica of the LEGO® Star Wars™ X-Wing starfighter, in New York’s Times Square. (Used by permission,© 2012 The LEGO Group)

The LEGO Group recently unveiled the world’s largest LEGO model, a 1:1 replica of the LEGO® Star Wars™ X-Wing starfighter, in New York’s Times Square.  (Used by permission, © 2012 The LEGO Group)

NASA is teaming up with LEGO to  inspire a new generation of space explorers.

The US space agency and the LEGO group, creator of the popular building brick and model construction kits, are challenging young people to envision the future through a competition called NASA’s Missions: Imagine and Build.

The contest calls on young people to share that vision by using LEGO pieces to create models of future NASA missions and spacecraft.

“It is international in scope…one class is for ages 13 and older and the other one is for ages 16 and older,” said Debbie Rivera, acting director of NASA’s Public Outreach Division.

Called "NASA’s Missions: Imagine and Build" - toy maker Lego and NASA have teamed up for a competition to encourage young people to envision the future of space exploration (LEGO/NASA)

Toy maker LEGO and NASA are sponsoring a competition that encourages young people to envision the future of space exploration. (LEGO/NASA)

You can enter the contest by registering online.

One of the two categories in the competition is  Inventing Our Future in Flight, which asks competitors to create an aircraft of the future based on a project NASA is currently working on.

The other category, Imagine Our Future Beyond Earth, encourages entrants to journey into space by using LEGOS to depict one of NASA’s future missions.

Although participants can be as imaginative as they wish, the entries should reflect a future mission NASA is already planning through the 2030s.

Participants will be able to use the LEGO digital designer computer program to help design their models.

Artist's Concept of a Solar Electric Propulsion-based spacecraft. Using advanced Solar Electric Propulsion (SEP) technologies is an essential part of future missions into deep space with larger payloads. (Analytical Mechanics Associates/NASA)

Artist’s concept of a solar electric propulsion-based spacecraft. Advanced technologies are an essential part of future missions into deep space. (Analytical Mechanics Associates/NASA)

Entrants will upload pictures of their completed models to any public web-server or photo sharing site such as flickr.com, and then post a link to their pictures on the contest website.

“There will be prizes for the winners, one of which is going to be a LEGO building kit that will be autographed by one of the LEGO designers,” said Rivera. “For one of the contests there will also be an actual trophy that is built out of LEGO bricks. And for winners in both contests there will be NASA commemorative material.”

The deadline for the contest is July 31, 2013 at 1259 UTC.

Ultra-Light Planet Found Outside Solar System

Posted June 4th, 2013 at 6:28 pm (UTC+0)
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The blue dot is the new exoplanet HD95086B image was taken by ESO's Very Large Telescope in Chile (ESO)

The blue dot is the newly discovered exoplanet, HD95086B, which was captured by ESO’s Very Large Telescope (VLT) in Chile. (ESO)

The European Southern Observatory (ESO) has discovered what appears to be the lightest planet ever to be directly observed outside of our Solar System.

Astronomers made the discovery using the Very Large Telescope (VLT), located in Chile, which captured the faint object moving near a bright star about 300 light years from Earth. The possible planet has an estimated mass  that is four-to-five times that of Jupiter.

Dubbed HD95086b, the planet appears in ESO’s observations as a faint but clear dot close to the star HD95086, which astronomers consider a fairly young star – about 10 to 17 million years old.

The star itself is a little more massive than the Sun and is surrounded by a debris disc, a disk of dust and debris orbiting a star. It was those properties that allowed ESO astronomers to identify the star as an ideal candidate to harbor young massive planets. Astronomers believe the new exoplanet was probably formed within that gaseous and dusty debris disc.

ESO's Very Large Telescope Array on Cerro Paranal Mountain (ESO)

ESO’s Very Large Telescope (VLT) Array on Cerro Paranal Mountain (ESO)

“Its current location raises questions about its formation process. It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc,” said Anne-Marie Lagrange, a member of the team that made the discovery. “Interactions between the planet and the disc itself or with other planets may have also moved the planet from where it was born.”

Later observations  indicated the planetary object moved with the star across the sky, suggesting that it is in orbit with the star.

HD95086 b is believed to orbit its young star at a distance of around 56 times the distance from the Earth to the Sun and twice distance between the Sun and Neptune.

Considering the brightness of its star, ESO astronomers estimate the surface temperature of HD95086b is about 700 degrees Celsius.

Image of the sky around the young star HD95086 in the southern constellation of Carina (The Keel). It was created from images from the Digitized Sky Survey 2.  (ESO)

Image of the sky around the young star HD95086 in the southern constellation of Carina (The Keel).  (ESO)

“This is cool enough for water vapor and possibly methane to exist in its atmosphere. It will be a great object to study with the forthcoming SPHERE instrument on the VLT. Maybe it can also reveal inner planets in the system, if they exist,” said Gaël Chauvin, another member of the team.

Astronomers were able to capture an image of HD95086 b, which is unusual. Most exoplanets are too far away to be properly imaged.

Experts usually have to rely on indirect methods to find planets, such as looking for a star to dim slightly which may be caused by a planet crossing in front of it. The ESO says there are only about 12 extrasolar or exoplanets that have been discovered using direct imaging.

“Direct imaging of planets is an extremely challenging technique that requires the most advanced instruments, whether ground-based or in space,” says Julien Rameau of the Institute of Planetology and Astrophysics in Grenoble, France who is first author of the paper announcing the discovery. “Only a few planets have been directly observed so far, making every single discovery an important milestone on the road to understanding giant planets and how they form.”

Evidence of Water Found on Mars

Posted May 31st, 2013 at 6:22 pm (UTC+0)
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NASA's Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named "Hottah". (NASA/JPL)

NASA’s Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named “Hottah.” (NASA)

The Curiosity rover has discovered an ancient stream bed that suggests water, possibly lots of it, once flowed on Mars.

In a new study,  scientists say their findings represent the first on-site evidence of sustained water flow on the Martian landscape. The discovery also supports the theory Mars would have once been able to host life.

Dawn Sumner, a co-author of the study, said  she and her colleagues used very basic geologic principles in making their discovery.  While examining high-resolution photographs of multiple outcrops of pebble-rich slabs  shot by Curiosity, they noticed some rounded pebbles.

“On the first day of my sedimentary class, I have the students measure grain size and the rounding,” said Sumner, who is a University of California-Davis geologist and professor. “It’s simple, and it’s important.”

Sumner said the pebbles’ rounded shape and granular size, along with other characteristics, can only form when pebbles are transported through water over long distances.

The pebbles, which were likely deposited more than two billion years ago, were discovered at three locations on Mars, known as Goulburn, Link and Hottah, which are located between the north rim of the planet’s Gale Crater and the base of a mountain located in the crater called Mount Sharp, about a quarter mile away from where Curiosity landed last summer.

Up close is the gravelly area around the Curiosity’s landing site in Gale Crater, in the distance is Mt. Sharp. (Photo: NASA/JPL-Caltech/MSSS)

In the foreground is the gravelly area around Curiosity’s landing site in Gale Crater. Mt. Sharp is seen in the distance. (NASA)

Sumner is also a co-investigator for the Mars Science Laboratory team and played an important role in selecting Gale Crater as Curiosity’s landing site.  She also helped coordinate the first scientific interpretations of what the rover saw during its first few days on the Red Planet, by controlling it with a computer to take photographs of its surroundings.

“The main reason we chose Gale Crater as a landing site was to look at the layered rocks at the base of Mount Sharp, about five miles away,” she said. “We knew there was an alluvial fan in the landing area, a cone-shaped deposit of sediment that requires flowing water to form. These sorts of pebbles are likely because of that environment. So while we didn’t choose Gale Crater for this purpose, we were hoping to find something like this.”

You can hear Dr. Sumner talk about her team’s discovery and the role geology is playing in the Curiosity’s goal of determining the “habitability” of Mars on this weekend’s radio edition of Science World – see right column for times and audio links.

Science Images of the Week

Posted May 28th, 2013 at 5:50 pm (UTC+0)
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Image of IC 2944 nebula, also known as the Running Chicken Nebula or the Lambda Cen Nebula taken by the European Southern Observatory's Very Large Telescope. (ESO)

The IC 2944 nebula, also known as the Running Chicken Nebula or the Lambda Cen Nebula, taken by the European Southern Observatory’s Very Large Telescope. (ESO)

During spring and fall, mass occurrences of the Asian lady beetle can often be observed. (Andreas Vilcinskas, Justus Liebig University, Giessen, Germany)

The Asian lady beetle, or Harmonia axyridis, is native to eastern Asia and was introduced in North America and Europe as a way to control pests such as aphids and scale insects. The insects have also made homes in South Africa and widely across South America. (Andreas Vilcinskas, Justus Liebig University, Giessen, Germany)

A Soyuz TMA-09M spacecraft is rolled out by train on Sunday, May 26, 2013 to the Baikonur Cosmodrome launch pad in Kazakhstan. (NASA/Bill Ingalls)

A Soyuz TMA-09M spacecraft is rolled out by train on Sunday, May 26, 2013, to the Baikonur Cosmodrome launch pad in Kazakhstan in preparation for today’s scheduled launch that will take three new crew members to the International Space Station. (NASA)

A up-close view of the 'Lung-on-a-Chip', a three-dimensional model of a living, breathing human lung on a microchip lined with human lung and blood vessel cells.  This device can mimic complex functions of the living lung. (Wyss Institute)

A up-close view of the Lung-on-a-Chip, a three-dimensional model of a living, breathing human lung on a microchip lined with human lung and blood vessel cells. By mimicking the complex functions of the living lung, scientists may be able to some day replace animals in testing drugs and toxins. (Wyss Institute)

Engineer uses a focused-ion beam instrument to prepare samples of organic solar cell material for imaging under an electron microscope. (Brookhaven National Laboratory)

Engineer uses a focused-ion beam instrument to prepare samples of organic solar cell material for imaging under an electron microscope. (Brookhaven National Laboratory)

Abundant corals are shown in a shallow Hawaiian lagoon. (Keoki Stender)

Abundant corals in a shallow Hawaiian lagoon. (Keoki Stender)

A supermassive black hole at the center of this galaxy 850 million light years from Earth generates two powerful jets of particles that are speeding out at millions of kilometers per hour (NASA\NSF\NRAO\VLA)

A super-massive black hole at the center of this galaxy 850 million light years from Earth generates two powerful jets of particles that are speeding out at millions of kilometers per hour. (NASA)

Close up of a 'tawny crazy ant' or 'raspberry crazy ant' an invasive species that has become so “ecologically dominant” that its even driving vicious fire ants from their homes. (Joe MacGown, Mississippi Entomological Museum)

Close up of a ‘tawny crazy ant’ or ‘raspberry crazy ant’ an invasive species that has become so ecologically dominant that scientists have observed them driving vicious fire ants from their homes in Texas and the Southeast US. (Joe MacGown, Mississippi Entomological Museum)

Technicians inspect primary mirror segments that will be used on the James Webb Space Telescope scheduled for launch in 2018. (NASA/Chris Gunn)

Technicians inspect primary mirror segments that will be used on the James Webb Space Telescope scheduled for launch in 2018. (NASA)

An Old German owl breed of domestic pigeon. Researchers at the University of Utah have identified a gene that is responsible for the fancy head crests of rock pigeons.(Sydney Stringham)

An Old German Owl breed of domestic pigeon. Researchers at the University of Utah have identified a gene that is responsible for the fancy head crests of rock pigeons. (Sydney Stringham)

Arctic Bacterium Offers Clues to Life on Mars

Posted May 24th, 2013 at 6:44 pm (UTC+0)
1 comment

Microscopic view of , Planococcus halocryophilus OR1 (McGill University)

Microscopic view of  Planococcus halocryophilus OR1 (McGill University)

A permafrost microbe has been discovered growing at –15°C, the coldest temperature ever reported for bacterial growth.

A team of scientists from Montreal’s McGill University made the discovery on Ellesmere Island, located in the Canadian High Arctic.

Researchers said they  found the living strain of bacteria growing in the extreme cold of the  permafrost, which may offer insight into possibilities of life existing beyond Earth.

The bacterium, Planococcus halocryophilus OR1, not only survives, but thrives in the permanently frozen sub-soil. Finding the microbe in the briny conditions of the Arctic could provide some hints about what it would take for microbial life to survive in conditions  found on the Saturn moon, Enceladus, or Mars, where similar frigid conditions are thought to exist.

The researchers examined about 200 separate types of microbes from the high Arctic before they found the microorganism that was best adapted to the harsh conditions of the Arctic permafrost.

”We believe that this bacterium lives in very thin veins of very salty water found within the frozen permafrost on Ellesmere Island,” said McGill professor Lyle Whyte who co-led the research team. “The salt in the permafrost brine veins keeps the water from freezing at the ambient permafrost temperature creating a habitable but very harsh environment. It’s not the easiest place to survive but this organism is capable of remaining active  to at least -25ºC in permafrost.”

To make their discovery, the research team studied the genomic sequence and other molecular characteristics of the P. halocryophilus OR1 microbe. The researchers found the bacterium adapts quite well to its bitter cold and salty environment, thanks to significant adjustments in its cell structure and function, as well as having increased amounts of cold-adapted proteins. Some of these cellular modifications also include changes to the membranes that envelop the microbe and protect it from its hostile environment.

Research team leaders Lyle Whyte (l) and Nadia Mykytczuk (r) (McGill University)

Research team leaders Lyle Whyte (l) and Nadia Mykytczuk (r) (McGill University)

After studying the microbe’s genome sequence, the scientists also discovered the bacterium is unusual in other ways;  it seems to have the ability to maintain high levels of compounds within the bacterial cell that act like molecular antifreeze, keeping the microorganism from not only from freezing solid but protects it from the salty environment.

“I’m kind of proud of this bug. It comes from the Canadian High Arctic and is our cold temperature champion, but what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system,” said research co-leader Nadia Mykytczuk.

The researchers agree concerned with one possibly troubling aspect of the microbe.  They think  the living microorganisms can harm the bitter cold environment of areas such as the high Arctic by increasing the amount of carbon dioxide emissions from the permafrost which is now melting due to what many scientists believe is global warming.

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