Tag: allowing (page 2 of 13)

6 Natural Solutions To Decontaminate Soil

May 2, 2015 / / 0 Comments

Marco Torres, Prevent DiseaseWith a progressively educated population becoming more aware of the inherent dangers of the conventional food supply, urban farming has become hugely popular. However, more people are also becoming aware of contaminated soil and how heavy metals pose potential risks to their food crops. As backyard gardening continues to explode in popularity, we must ask how contaminated is our soil?Many municipalities in many countries are embracing urban agri [...]

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NASA application grants general public the opportunity to explore the surface of Vesta

April 28, 2015 / / 0 Comments

NASA's Dawn spacecraft visited Vesta for a year before continuing on to Ceres (Image: NASA/JPL-Caltech) Excerpt from gizmag.comNASA has released a browser-based application that allows citizen scientists to explore the surface of the asteroid V...

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Is In-Flight Refueling Coming to Commercial Airlines?

April 12, 2015 / / 0 Comments




Excerpt from space.com

 This article was originally published on The Conversation. The publication contributed this article to Space.com's Expert Voices: Op-Ed & Insights.

There’s real pressure on the aviation industry to introduce faster, cheaper and greener aircraft, while maintaining the high safety standards demanded of airlines worldwide.

Airlines carry more than three billion passengers each year, which presents an enormous challenge not only for aircraft manufacturers but for the civil aviation infrastructure that makes this extraordinary annual mass-migration possible. Many international airports are close to or already at capacity. The International Air Transport Association (IATA) has estimated that, without intervention, many global airports – including major hubs such as London Heathrow, Amsterdam Schiphol, Beijing and Dubai – will have run out of runway or terminal capacity by 2020. 


The obvious approach to tackling this problem is to extend and enlarge airport runways and terminals – such as the long-proposed third runway at London Heathrow. However there may be other less conventional alternatives, such as introducing in-flight refuelling for civil aircraft on key long-haul routes. Our project, Research on a Cruiser-Enabled Air Transport Environment (Recreate), began in 2011 to evaluate whether this was something that could prove a viable, and far cheaper, solution.

If in-flight refuelling seems implausible, it’s worth remembering that it was first trialed in the 1920s, and the military has continued to develop the technology ever since. The appeal is partly to reduce the aircraft’s weight on take-off, allowing it to carry additional payload, and partly to extend its flight range. Notably, during the Falklands War in 1982 RAF Vulcan bombers used in-flight refuelling to stage what was at the time the longest bombing mission ever, flying 8,000 miles non-stop from Ascension Island in the South Atlantic to the Falklands and back.

Reducing take-off weight could offer many benefits for civilian aircraft too. Without the need to carry so much fuel the aircraft can be smaller, which means less noise on take-off and landing and shorter runways. This opens up the network of smaller regional airports as new potential sites for long-haul routes, relieving pressure on the major hubs that are straining at the seams.

There are environmental benefits too, as a smaller, lighter aircraft requires less fuel to reach its destination. Our initial estimates from air traffic simulations demonstrate that it’s possible to reduce fuel burn by up to 11% over today’s technology by simply replacing existing global long-haul flight routes with specifically designed 250-seater aircraft with a range of 6,000nm after one refuelling – roughly the distance from London to Hong Kong. This saving could potentially grow to 23% with further efficiencies, all while carrying the same number of passengers the same distance as is possible with the current aircraft fleet, and despite the additional fuel burn of the tanker aircraft.

Tornado fighter jets in-flight refuel
Imagine if these Tornado fighter jets were 250-seater passenger aircraft and you’ve got the idea.

However, this is not the whole picture – in-flight refuelling will require the aerial equivalent of petrol stations in order to deliver keep passenger aircraft in the sky. With so much traffic it simply wouldn’t be possible to refuel any aircraft any time, anywhere it was needed. The location of these refuelling zones, coupled with the flight distance between the origin and destination airports can greatly affect the potential benefits achievable, possibly pulling flights away from their shortest route, and even making refuelling on some routes impossible – if for example the deviation to the nearest refuelling zone meant burning as much fuel as would have been saved.

Safety and automation

As with all new concepts – particularly those that involve bringing one aircraft packed with people and another full of fuel into close proximity during flight – it’s quite right to ask whether this is safe. To try and answer this question, the Dutch National Aerospace Laboratory and German Aerospace Centre used their flight simulators to test the automated in-flight refuelling flight control system developed as part of the Recreate project.

One simulator replicated the manoeuvre from the point of view of the tanker equipped with an in-flight refuelling boom, the other simulated the aircraft being refuelled mid-flight. Critical test situations such as engine failure, high air turbulence and gusts of wind were simulated with real flight crews to assess the potential danger to the operation. The results were encouraging, demonstrating that the manoeuvre doesn’t place an excessive workload on the pilots, and that the concept is viable from a human as well as a technical perspective.

So far we’ve demonstrated the potential aerial refuelling holds for civilian aviation, but putting it into practice would still pose challenges. Refuelling hubs would need to be established worldwide, shared between airlines. There would need to be fundamental changes to airline pilot training, alongside a wider public acceptance of this departure from traditional flight operations.

However, it does demonstrate that, in addition to all the high-tech work going into designing new aircraft, new materials, new engines and new fuels, the technology we already have offers solutions to the long-term problems of ferrying billions of passengers by air around the world.

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Discovered: A ‘Treasure Chest’ of Ancient Galaxies

March 31, 2015 / / 0 Comments


full sky planck
The full visible sky as seen by the Planck space observatory. The band running through the middle corresponds to dust in our Milky Way galaxy. The black dots indicate the location of the proto-cluster candidates identified by Planck and subsequently observed by the Herschel space telescope. (Photo : ESA and the Planck Collaboration)


Excerpt from natureworldnews.com

Treasure seekers have found the haul of a lifetime, but it wasn't in some ancient temple or mysterious island. Instead, it was in the sky. Researcher using two of the European Space Agency's (ESA) impressive space telescopes have successfully identified what they are calling a "treasure chest" of ancient galaxy clusters, which could help explain how the Universe came to be the way it is today.

That's at least according to a study recently published (PDF) in the journal Astronomy and Astrophysics, which details how cosmologists used the ESA's Planck space observatory to identify the distant precursor galaxy clusters, and then poured over data from the Herschel telescope for a closer look.

"Finding so many intensely star-forming, dust galaxies in such concentrated groups was a huge surprise," Hervé Dole, lead author of the report from the Institut d'Astrophysique Spatiale in France, said in a statement. "We think this is a missing piece of cosmological structure formation."

So what does he mean by that? Let's turn back to the treasure chest metaphor for this one.  While Planck was the space observatory to dig up the chest, it was the Herschel data that allowed experts to look closely at each and every gold coin (galaxy cluster) inside. Now they are able to learn more about each coin's make, mint, and ultimately, its origins.

And that's a big step in better understanding the early Universe. Expects believe that it took a great deal of time after star and galaxies first sprung to life for them to assemble into large clusters. 

A summary of the 14 billion years out Universe has been in existence, as seen by the Plank space telescop. Light coming from some of the oldest parts of the Universe are just reaching the observatory now, allowing for experts to see the incredible uniformity of the early structure, compared to the chaotic beautify of star, galaxy, and cluster formation that crowd space today.
(Photo : ESA – C. Carreau) A summary of the 14 billion years out Universe has been in existence, as seen by the Plank space telescope. Light coming from some of the oldest parts of the Universe are just reaching the observatory now, allowing for experts to see the incredible uniformity of the early matter, compared to the chaotic beautify of star, galaxy, and cluster formation that crowds space today.
Once the clusters formed, their gravitational influence triggered the creation of new stars and galaxies. Dark matter - which is theorized to account for a great deal of each cluster's mass and influence - helped usher along the process of creating stars. But how these large clusters were ultimately assembled and grew is still a mystery.
That's why looking at some of the oldest 'coins' ever made - estimated to date back to up-to 11 billion light-years ago - could be exceptionally helpful.

"We still have a lot to learn about this new population," Dole said in an ESA release. "Hints of these kinds of objects had been found earlier in data from Herschel and other telescopes, but the all-sky capability of Planck revealed many more candidates for us to study."

"Even when we combined the powerful capabilities of Planck and Herschel, we were only scratching the surface of the phenomena taking place at this critical era in the history of our universe, when stars, galaxies and clusters seem to be forming simultaneously," 
added George Helou, director of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. "That's one of the reasons this finding is exciting. It shows us that there is so much more to be learned.

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Why Luke Skywalker’s binary sunset may be real after all

March 30, 2015 / / 0 Comments






Excerpt from csmonitor.com

Researchers have found Jupiter-scale gas giants orbiting binary stars and estimate that Earth-like planets orbiting binary stars could be as numerous as rocky planets orbiting single-star systems.


For all the sci-fi charm of watching a pair of suns sink below a distant horizon on a planet in a galaxy far, far away, conventional wisdom has held that binary-star systems can't host Earth-scale rocky planets.

As the two stars orbit each other like square-dance partners swinging arm in arm, regular variations in their gravitational tug would disrupt planet formation at the relatively close distances where rocky planets tend to appear.

Not so fast, say two astrophysicists. They argue that only are Tatooine-like planets likely to be out there. They could be as numerous as rocky planets orbiting single-star systems – which is to say, there could be large number of them.

Building rocky planets in a binary system not only is possible, it's "not even that hard," says Scott Kenyon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who along with University of Utah astrophysicist Benjamin Bromley performed the calculations.
Researchers have found Jupiter-scale gas giants orbiting binary stars and have estimated that such gas giants are likely to be as common in binary systems as they are in systems with a single star.
"If that's true, then Earth-like planets around binaries are just as common as Earth-like planets around single stars," Dr. Kenyon says. "If they're not common, that tells you something about how they form or how they interact with the star over billions of years."

The modeling study grew out of work the two researchers were undertaking to figure out how the dwarf planet Pluto and its largest moon Charon manage to share space with four smaller moons that orbit the two larger objects. 

Pluto and Charon form a binary system that early in its history saw the two objects graze each other to generate a ring of dust that would become the additional moons.

The gravity the surrounding dust felt as Pluto and Charon swung about their shared center of mass would vary with clock-like precision.

Conventional wisdom held that this variable tug would trigger collisions at speeds too fast to allow the dust and larger chunks to merge into ever larger objects.

Kenyon and Dr. Bromley found that, in fact, the velocities would be smaller than people thought – no greater than the speeds would be around a single central object, where velocities are slow enough to allow the debris to bump gently and merge to build ever-larger objects.

They recognized that binary stars hosting planets are essentially scaled-up versions of the Pluto-Charon system. So they applied their calculations to a hypothetical binary star system with a circumstellar disk of dust and debris.

"The modest jostling in these orbits is the same modest jostling you'd get around a single star," Kenyon says, allowing rocky inner planets to form.

As for the Jupiter- or Neptune-scale planets found around binary stars, they would have formed farther out and migrated in over time, the researchers say, since there is too little material within the inner reaches of a circumstellar disk to build giant planets.

The duo's calculations imply that as more planets are discovered orbiting binary stars, a rising number of Tatooines will be among them. 

Tatooine "was science fiction," Kenyon says. But "it's not so far from science reality."

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Cleaning Up Old Satellites And Space Junk Could Soon Be Done With Giant Fishing Nets

March 28, 2015 / / 0 Comments

Excerpt from techtimes.com Spacecraft are all shiny and new when they leave Earth but being up in space can do a number on them, resulting into bits and pieces of junk flying around. The European Space Agency's Clean Space initiative is looking to l...

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Scientist Claims to Discover Sounds of Stars

March 24, 2015 / / 0 Comments






Excerpt from clapway.com

If you can remember your primary school’s astronomy classes, the surface of a star is a very volatile place with tons of chemical reactions and extreme motions, and with immense gravitational pull. Generally a place you would not want to be. But researchers are now saying that if you were to orbit a star, it may be possible, with the right equipment, to hear what a star is saying! Or Singing?
Would you want to hear the sounds of stars?

The sound, unfortunately, is so high pitched that no mammal, not even a dolphin or bat, would be able to hear it, and couldn’t be heard anyway because space is a vacuum and there is no air medium for the sound to travel in.

With a frequency of nearly one trillion hertz, the sound was not only unexpected, but six million times higher than what any mammal can hear. But the researchers have developed a method to hear what they poetically refer to as “singing” or a star’s “song.”

Britain’s University of York’s researchers of hydrodynamics – the study of fluids in motion – fired a laser beam at the plasma in the laboratory and found that within a trillionth of a second, the plasma quickly moved from high-density to low-density areas.Plasma is a state of matter that makes up most things in the known universe and a few things on earth like lightning strikes and neon signs. It is basically a gas that has been charged with enough energy to loose the electrons from the atoms holding them together.

The spot where the low-density and high-density areas meet led to what the University researchers called a “traffic jam,” and resulted in an apparent sound wave, allowing us to know the sounds of stars.

Though this was achieved in the laboratory, scientists have yet to try to hear the sounds of a real star.

Dr. Pasley, a scientist from the Tata Institute of Fundamental Research in Mumbai, India, , said: “One of the few locations in nature where we believe this effect would occur is at the surface of stars. When they are accumulating new material stars could generate sound in a very similar manner to that which we observed in the laboratory–so the stars might be singing–but since sound cannot propagate through the vacuum of space, no-one can hear them.”

The technique used to observe the sound waves in the laboratory sort of works like a police speed camera, allowing scientists to accurately measure how the fluid would sound at the point of being struck by the laser at very minute timescales. The research was published in Physical Review Letters.

Perhaps in the future we might be able to listen in on the sounds of stars instead of just viewing it, and hear what they have to say!

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Young Jupiter wiped out solar system’s early inner planets, study says

March 24, 2015 / / 0 Comments


Ganymede
(Photo : NASA/ESA) In early days of solar system, Jupiter destroyed everything that came in its way, researchers have found.


Excerpt from latimes.com

Before Mercury, Venus, Earth and Mars occupied the inner solar system, there may have been a previous generation of planets that were bigger and more numerous – but were ultimately doomed by Jupiter, according to a new study.

If indeed the early solar system was crowded with so-called super-Earths, it would have looked a lot more like the planetary systems found elsewhere in the galaxy, scientists wrote Monday in the Proceedings of the National Academy of Sciences.


Inner planets
As NASA’s Kepler space telescope has found more than 1,000 planets in orbit around other stars, along with more than 4,000 other objects that are believed to be planets but haven’t yet been confirmed. Kepler finds these planets by watching their host stars and registering tiny drops in their brightness – a sign that they are being ever-so-slightly darkened by a planet crossing in front of them.

In addition, ground-based telescopes have detected hundreds of exoplanets by measuring the wiggles of distant stars. Those stars wiggle thanks to the gravitational pull of orbiting planets, and the Doppler effect makes it possible to estimate the size of these planets.

The more planetary systems astronomers discovered, the more our own solar system looked like an oddball. Exoplanets – at least the ones big enough for us to see – tended to be bigger than Earth, with tight orbits that took them much closer to their host stars. In multi-planet systems, these orbits tended to be much closer together than they are in our solar system. For instance, the star known as Kepler-11 has six planets closer to it than Venus is to the sun.

Why does our solar system look so different? Astrophysicists Konstantin Batygin of Caltech and Greg Laughlin of UC Santa Cruz summed it up in one word: Jupiter.

Here’s what could have happened, according to their models:

In Solar System 1.0, the region closest to the sun was occupied by numerous planets with masses several times bigger than that of Earth. There were also planetesimals, “planetary building blocks” that formed within the first million years after the birth of the sun, Batygin and Laughlin wrote.

This is how things might have stayed if the young Jupiter had stayed put at its initial orbit, between 3 and 10 astronomical units away from the sun. (An astronomical unit, or AU, is the distance between the Earth and the sun. Today, Jupiter’s orbit ranges between 5 and 5.5 AUs from the sun.)

But Jupiter was restless, according to a scenario known as the “Grand Tack.” In this version of events, Jupiter was swept up by the currents of gas that surrounded the young sun and drifted toward the center of the solar system.

Jupiter, however, was too big to travel solo. All manner of smaller objects would have been dragged along too. With so many bodies in motion, there would have been a lot of crashes.

The result was “a collisional cascade that grinds down the planetesimal population to smaller sizes,” the astrophysicists wrote. For the most part, these planetary crumbs were swept toward the sun and ultimately destroyed, like disintegrating satellites falling back to Earth.

The planetesimals wouldn’t have been Jupiter’s only victims. Assuming the early solar system resembled the planetary systems spied by Kepler and other telescopes, there would have been “a similar population of first-generation planets,” the pair wrote. “If such planets formed, however, they were destroyed.”

Jupiter probably got about as close to the sun as Mars is today before reversing course, pulled away by the gravity of the newly formed Saturn. That would have ended the chaos in the inner solar system, allowing Earth and the other rocky planets to form from the debris that remained.

“This scenario provides a natural explanation for why the inner Solar System bears scant resemblance to the ubiquitous multi-planet systems” discovered by Kepler and other survey efforts, Batygin and Laughlin wrote.

Although their models show that this is what might have happened, they don’t prove that it actually did. But there may be a way to get closer to the truth.

The scientists’ equations suggest that if a star is orbited by a cluster of close-in planets, there won’t be a larger, farther-out planet in the same system. As astronomers find more exoplanetary systems, they can see whether this prediction holds up.

Also, if far-away solar systems are experiencing a similar series of events, telescopes ought to be able to detect the extra heat thrown off by all of the planetesimal collisions, they added.

Sadly for those hoping to find life on other planets, the pair’s calculations also imply that most Earth-sized planets are lacking in water and other essential compounds that can exist in liquid or solid form. As a result, they would be “uninhabitable,” they wrote.

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Is Titan submarine the most daring space mission yet?

March 19, 2015 / / 0 Comments

The submersible could extract cores from the seabed to unlock a rich climatic historyExcerpt from bbc.comDropping a robotic lander on to the surface of a comet was arguably one of the most audacious space achievements of recent times. But one...

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Billionaire teams up with NASA to mine the moon

March 10, 2015 / / 0 Comments




Excerpt from cnbc.com
By Susan Caminiti



Moon Express, a Mountain View, California-based company that's aiming to send the first commercial robotic spacecraft to the moon next year, just took another step closer toward that lofty goal. 

Earlier this year, it became the first company to successfully test a prototype of a lunar lander at the Kennedy Space Center in Florida. The success of this test—and a series of others that will take place later this year—paves the way for Moon Express to send its lander to the moon in 2016, said company co-founder and chairman Naveen Jain.

Moon Express conducted its tests with the support of NASA engineers, who are sharing with the company their deep well of lunar know-how. The NASA lunar initiative—known as Catalyst—is designed to spur new commercial U.S. capabilities to reach the moon and tap into its considerable resources.In addition to Moon Express, NASA is also working with Astrobotic Technologies of Pittsburgh, Pennsylvania, and Masten Space Systems of Mojave, California, to develop commercial robotic spacecrafts. 

Jain said Moon Express also recently signed an agreement to take over Space Launch Complex 36 at Cape Canaveral. The historic launchpad will be used for Moon Express's lander development and flight-test operations. Before it was decommissioned, the launchpad was home to NASA's Atlas-Centaur rocket program and its Surveyor moon landers.

"Clearly, NASA has an amazing amount of expertise when it comes to getting to the moon, and it wants to pass that knowledge on to a company like ours that has the best chance of being successful," said Jain, a serial entrepreneur who also founded Internet companies Infospace and Intelius. He believes that the moon holds precious metals and rare minerals that can be brought back to help address Earth's energy, health and resource challenges. 

Among the moon's vast riches: gold, cobalt, iron, palladium, platinum, tungsten and Helium-3, a gas that can be used in future fusion reactors to provide nuclear power without radioactive waste. "We went to the moon 50 years ago, yet today we have more computing power with our iPhones than the computers that sent men into space," Jain said. "That type of exponential technological growth is allowing things to happen that was never possible before."

An eye on the Google prize

Source: MoonExpress

Helping to drive this newfound interest in privately funded space exploration is the Google Lunar X Prize. It's a competition organized by the X Prize Foundation and sponsored by Google that will award $30 million to the first company that lands a commercial spacecraft on the moon, travels 500 meters across its surface and sends high-definition images and video back to Earth—all before the end of 2016.

Moon Express is already at the front of the pack. In January it was awarded a $1 million milestone prize from Google for being the only company in the competition so far to test a prototype of its lander. "Winning the X prize would be a great thing," said Jain. "But building a great company is the ultimate goal with us." When it comes to space exploration, he added, "it's clear that the baton has been passed from the government to the private sector."

Testing in stages

Jain said Moon Express has been putting its lunar lander through a series of tests at the space center. The successful outing earlier this year involved tethering the vehicle—which is the size of a coffee table—to a crane in order to safely test its control systems. "The reason we tethered it to the crane is because the last thing we wanted was the aircraft to go completely haywire and hurt someone," he said. 

At the end of March, the company will conduct a completely free flight test with no tethering. The lander will take off from the pad, go up and sideways, then land back at the launchpad. "This is to test that the vehicle knows where to go and how to get back to the launchpad safely," Jain explained.


Once all these tests are successfully completed, Jain said the lander—called MX-1—will be ready to travel to the moon. The most likely scenario is that it will be attached to a satellite that will take the lander into a low orbit over the Earth. From there the MX-1 will fire its own rocket, powered by hydrogen peroxide, and launch from that orbit to complete its travel to the moon's surface. 

The lander's first mission is a one-way trip, meaning that it's not designed to travel back to the Earth, said Jain. "The purpose is to show that for the first time, a company has developed the technology to land softly on the moon," he said. "Landing on the moon is not the hard part. Landing softly is the hard part." 

That's because even though the gravity of the moon is one-sixth that of the Earth's, the lander will still be traveling down to the surface of the moon "like a bullet," Jain explained. Without the right calculations to indicate when its rockets have to fire in order to slow it down, the lander would hit the surface of the moon and break into millions of pieces. "Unlike here on Earth, there's no GPS on the moon to tell us this, so we have to do all these calculations first," he said. 

Looking ahead 15 or 20 years, Jain said he envisions a day when the moon is used as a sort of way station enabling easier travel for exploration to other planets. In the meantime, he said the lander's second and third missions could likely involve bringing precious metals, minerals and even moon rocks back to Earth. "Today, people look at diamonds as this rare thing on Earth," Jain said.
He added, "Imagine telling someone you love her by giving her the moon."

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Warp in spacetime lets astronomers watch the same star explode four times

March 8, 2015 / / 0 Comments



Excerpt from csmonitor.com

Thanks to a phenomenon known as gravitational lensing, the Hubble Space Telescope has captured four images of the same supernova explosion.

For the first time, a cosmic magnifying glass has allowed scientists to see the same star explosion four times, possibly offering a revealing glimpse into these explosive stellar deaths and the nature of the accelerating universe.

Astronomers using the Hubble Space Telescope have captured four images of a supernova explosion in deep space thanks to a galaxy located between Earth and the massive star explosion. You can see how Hubble saw the supernova in this NASA video. The galaxy cluster warped the fabric of space and time around it — like a bowling ball placed on a bed sheet — allowing scientists to see the supernova in four images.

"It was predicted 50 years ago that a supernova could be gravitationally lensed like this, but it's taken a long time for someone to find an example," lead study author Patrick Kelly, an astronomer at the University of California, Berkeley told Space.com. "It's fun to have been able to find the first one." 

The supernova, which was discovered on Nov. 11, 2014, is located about 9.3 billion light-years away from Earth, near the edge of the observable universe. The researchers have named the distant supernova SN Refsdal in honor of the late Norwegian astrophysicist Sjur Refsdal, a pioneer of gravitational lensing studies. Due to gravitational lensing, "the supernova appears 20 times brighter than its normal brightness," study co-author Jens Hjorth, head of the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen, said in a statement.
The lensing galaxy, which is about 5 billion light-years from Earth, is part of a large cluster of galaxies known MACS J1149.6+2223. In 2009, astronomers discovered that this cluster was the source of the largest known image of a spiral galaxy ever seen through a gravitational lens.

The four images of the supernova each appeared separately over the course of a few weeks. This is because light can take various paths around and through a gravitational lens, arriving at Earth at different times.

Using gravity as a lens

Gravity is created when matter warps the fabric of reality. The greater the mass of an object, the more space-time curves around that object and the stronger its gravitational pull, the discovery enshrined in Einstein's theory of general relativity, which celebrates its centennial this year.

As a result, gravity can also bend light like a lens, meaning objects see n behind powerful gravitational fields, such as those of massive galaxies, are magnified. Gravitational lensing was first discovered in 1979, and today gravitational lenses can help astronomers see features otherwise too distant and faint to detect with even the largest telescopes.

"These gravitational lenses are like a natural magnifying glass. It's like having a much bigger telescope," Kelly said in a statement. "We can get magnifications of up to 100 times by looking through these galaxy clusters."

When light is far from a gravitationally lensing mass, or if the gravitationally lensing mass is not especially large, only "weak lensing" occurs, barely distorting the light. However, when the light comes from almost exactly behind the gravitationally lensing mass, "strong lensing" can happen. 

When a strongly lensed object occupies a large patch of space — for instance, if it's a galaxy — it can get smeared into an "Einstein ring" surrounding a gravitationally lensing mass. However, strong lensing of small, pointlike items — for instance, super-bright objects known as quasars — often produces multiple images surrounding the gravitationally lensing mass, resulting in a so-called "Einstein cross."

The observations of SN Refsdal mark the first time astronomers on Earth have witnessed strong lensing of a  supernova, with four images of an exploding star arrayed as an Einstein cross.

An expanding universe

These new findings could help scientists measure the accelerating rate at which the universe is expanding, researchers say.

A computer model of the lensing cluster suggests the scientists missed chances to see the lensed supernova 50 and 10 years ago. However, the model also suggests more images of the explosion will repeat again within the next 10 years.

The timing of when all these images of the supernova arrive depends on the gravitational pull of the matter generating the gravitational lens. So, by measuring those times, the researchers hope to map how visible normal matter and invisible dark matter is distributed in the lensing galaxy.

Dark matter is currently one of the greatest mysteries in science, a poorly understood substance thought to make up five-sixths of all matter in the universe. A better understanding of how dark matter is behaving in this gravitationally lensing cluster might help shed light on the material's nature, Kelly said.

Analyzing when the images arrive could also help scientists pinpoint the rate at which the universe is expanding. Although there are already several ways to measure the cosmic expansion rate, "there has been a lot of heated debate between different methods, so it'd be interesting to see how this new technique might affect the area," Kelly said. "It's always nice to have completely independent measurements of the same quantity."

The scientists detailed their findings in the March 6 issue of the journal Science.

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What happens to your body when you give up sugar?

March 4, 2015 / / 0 Comments





Excerpt from independent.co.uk
By Jordan Gaines Lewis


In neuroscience, food is something we call a “natural reward.” In order for us to survive as a species, things like eating, having sex and nurturing others must be pleasurable to the brain so that these behaviours are reinforced and repeated.
Evolution has resulted in the mesolimbic pathway, a brain system that deciphers these natural rewards for us. When we do something pleasurable, a bundle of neurons called the ventral tegmental area uses the neurotransmitter dopamine to signal to a part of the brain called the nucleus accumbens. The connection between the nucleus accumbens and our prefrontal cortex dictates our motor movement, such as deciding whether or not to taking another bite of that delicious chocolate cake. The prefrontal cortex also activates hormones that tell our body: “Hey, this cake is really good. And I’m going to remember that for the future.”
Not all foods are equally rewarding, of course. Most of us prefer sweets over sour and bitter foods because, evolutionarily, our mesolimbic pathway reinforces that sweet things provide a healthy source of carbohydrates for our bodies. When our ancestors went scavenging for berries, for example, sour meant “not yet ripe,” while bitter meant “alert – poison!”
Fruit is one thing, but modern diets have taken on a life of their own. A decade ago, it was estimated that the average American consumed 22 teaspoons of added sugar per day, amounting to an extra 350 calories; it may well have risen since then. A few months ago, one expert suggested that the average Briton consumes 238 teaspoons of sugar each week.
Today, with convenience more important than ever in our food selections, it’s almost impossible to come across processed and prepared foods that don’t have added sugars for flavour, preservation, or both.
These added sugars are sneaky – and unbeknown to many of us, we’ve become hooked. In ways that drugs of abuse – such as nicotine, cocaine and heroin – hijack the brain’s reward pathway and make users dependent, increasing neuro-chemical and behavioural evidence suggests that sugar is addictive in the same way, too.

Sugar addiction is real

Anyone who knows me also knows that I have a huge sweet tooth. I always have. My friend and fellow graduate student Andrew is equally afflicted, and living in Hershey, Pennsylvania – the “Chocolate Capital of the World” – doesn’t help either of us. But Andrew is braver than I am. Last year, he gave up sweets for Lent. “The first few days are a little rough,” Andrew told me. “It almost feels like you’re detoxing from drugs. I found myself eating a lot of carbs to compensate for the lack of sugar.”
There are four major components of addiction: bingeing, withdrawal, craving, and cross-sensitisation (the notion that one addictive substance predisposes someone to becoming addicted to another). All of these components have been observed in animal models of addiction – for sugar, as well as drugs of abuse.
A typical experiment goes like this: rats are deprived of food for 12 hours each day, then given 12 hours of access to a sugary solution and regular chow. After a month of following this daily pattern, rats display behaviours similar to those on drugs of abuse. They’ll binge on the sugar solution in a short period of time, much more than their regular food. They also show signs of anxiety and depression during the food deprivation period. Many sugar-treated rats who are later exposed to drugs, such as cocaine and opiates, demonstrate dependent behaviours towards the drugs compared to rats who did not consume sugar beforehand.
Like drugs, sugar spikes dopamine release in the nucleus accumbens. Over the long term, regular sugar consumption actually changes the gene expression and availability of dopamine receptors in both the midbrain and frontal cortex. Specifically, sugar increases the concentration of a type of excitatory receptor called D1, but decreases another receptor type called D2, which is inhibitory. Regular sugar consumption also inhibits the action of the dopamine transporter, a protein which pumps dopamine out of the synapse and back into the neuron after firing.
In short, this means that repeated access to sugar over time leads to prolonged dopamine signalling, greater excitation of the brain’s reward pathways and a need for even more sugar to activate all of the midbrain dopamine receptors like before. The brain becomes tolerant to sugar – and more is needed to attain the same “sugar high.”

Sugar withdrawal is also real

Although these studies were conducted in rodents, it’s not far-fetched to say that the same primitive processes are occurring in the human brain, too. “The cravings never stopped, [but that was] probably psychological,” Andrew told me. “But it got easier after the first week or so.”
In a 2002 study by Carlo Colantuoni and colleagues of Princeton University, rats who had undergone a typical sugar dependence protocol then underwent “sugar withdrawal.” This was facilitated by either food deprivation or treatment with naloxone, a drug used for treating opiate addiction which binds to receptors in the brain’s reward system. Both withdrawal methods led to physical problems, including teeth chattering, paw tremors, and head shaking. Naloxone treatment also appeared to make the rats more anxious, as they spent less time on an elevated apparatus that lacked walls on either side.
Similar withdrawal experiments by others also report behaviour similar to depression in tasks such as the forced swim test. Rats in sugar withdrawal are more likely to show passive behaviours (like floating) than active behaviours (like trying to escape) when placed in water, suggesting feelings of helplessness.
A new study published by Victor Mangabeira and colleagues in this month’s Physiology & Behavior reports that sugar withdrawal is also linked to impulsive behaviour. Initially, rats were trained to receive water by pushing a lever. After training, the animals returned to their home cages and had access to a sugar solution and water, or just water alone. After 30 days, when rats were again given the opportunity to press a lever for water, those who had become dependent on sugar pressed the lever significantly more times than control animals, suggesting impulsive behaviour.
These are extreme experiments, of course. We humans aren’t depriving ourselves of food for 12 hours and then allowing ourselves to binge on soda and doughnuts at the end of the day. But these rodent studies certainly give us insight into the neuro-chemical underpinnings of sugar dependence, withdrawal, and behaviour.
Through decades of diet programmes and best-selling books, we’ve toyed with the notion of “sugar addiction” for a long time. There are accounts of those in “sugar withdrawal” describing food cravings, which can trigger relapse and impulsive eating. There are also countless articles and books about the boundless energy and new-found happiness in those who have sworn off sugar for good. But despite the ubiquity of sugar in our diets, the notion of sugar addiction is still a rather taboo topic.
Are you still motivated to give up sugar? You might wonder how long it will take until you’re free of cravings and side-effects, but there’s no answer – everyone is different and no human studies have been done on this. But after 40 days, it’s clear that Andrew had overcome the worst, likely even reversing some of his altered dopamine signalling. “I remember eating my first sweet and thinking it was too sweet,” he said. “I had to rebuild my tolerance.”
And as regulars of a local bakery in Hershey – I can assure you, readers, that he has done just that.
Jordan Gaines Lewis is a Neuroscience Doctoral Candidate at Penn State College of Medicine

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Another Problem for Evolution Theory? ‘Big Brain’ Gene Found in Humans, But Not in Chimps

February 27, 2015 / / 0 Comments



Image: Mouse brain
M. Florio and W. Huttner / Max Planck Institute
This embryonic mouse cerebral cortex was stained to identify cell nuclei (in blue) and a marker for deep-layer neurons (in red). The human-specific gene known as ARHGAP11B was selectively expressed in the right hemisphere: Note the folding of the neocortical surface.

Excerpt from  nbcnews.com

By Tia Ghose

ave the way for the rise of human intelligence by dramatically increasing the number of neurons found in a key brain region. 

This gene seems to be uniquely human: It is found in modern-day humans, Neanderthals and another branch of extinct humans called Denisovans, but not in chimpanzees. 

By allowing the brain region called the neocortex to contain many more neurons, the tiny snippet of DNA may have laid the foundation for the human brain's massive expansion.
"It is so cool that one tiny gene alone may suffice to affect the phenotype of the stem cells, which contributed the most to the expansion of the neocortex," said study lead author Marta Florio, a doctoral candidate in molecular and cellular biology and genetics at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany. 

She and her colleagues found that the gene, called ARHGAP11B, is turned on and highly activated in the human neural progenitor cells, but isn't present at all in mouse cells. This tiny snippet of DNA, just 804 genetic bases long, was once part of a much longer gene. Somehow, this fragment was duplicated, and the duplicated fragment was inserted into the human genome. 

In follow-up experiments, the team inserted and turned on this DNA snippet in the brains of mice. The mice with the gene insertion grew what looked like larger neocortex regions. 

The researchers reviewed a wide variety of genomes from modern-day and extinct species — confirming that Neanderthals and Denisovans had this gene, while chimpanzees and mice do not. That suggests that the gene emerged soon after humans split off from chimpanzees, and that it helped pave the way for the rapid expansion of the human brain. 

Florio stressed that the gene is probably just one of many genetic changes that make human cognition special.

The gene was described in a paper published online Thursday by the journal Science.

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