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Saturday, 29 November 2014

YOUNG VOLCANOES ON THE MOON

Nov 24, 2014: Back in 1971, Apollo 15 astronauts orbiting the Moon photographed something very odd.  Researchers called it "Ina," and it looked like the aftermath of a volcanic eruption. 
There's nothing odd about volcanoes on the Moon, per se.  Much of the Moon's ancient surface is covered with hardened lava. The main features of the "Man in the Moon," in fact, are old basaltic flows deposited billions of years ago when the Moon was wracked by violent eruptions. The strange thing about Ina was its age.
Planetary scientists have long thought that lunar volcanism came to an end about a billion years ago, and little has changed since. Yet Ina looked remarkably fresh. For more than 30 years Ina remained a mystery, a "one-off oddity" that no one could explain.
Turns out, the mystery is bigger than anyone imagined. Using NASA's Lunar Reconnaissance Orbiter, a team of researchers led by Sarah Braden of Arizona State University has found 70 landscapes similar to Ina.  They call them "Irregular Mare Patches" or IMPs for short.
"Discovering new features on the lunar surface was thrilling!" says Braden. "We looked at hundreds of high-resolution images, and when I found a new IMP it was always the highlight of my day."
"The irregular mare patches look so different than more common lunar features like impact craters, impact melt, and highlands material," she says.  "They really jump out at you."
On the Moon, it is possible to estimate the age of a landscape by counting its craters.  The Moon is pelted by a slow drizzle of meteoroids that pepper its surface with impact scars.  The older a landscape, the more craters it contains.
Some of the IMPs they found are very lightly cratered, suggesting that they are no more than 100 million years old. A hundred million years may sound like a long time, but in geological terms it's just a blink of an eye. The volcanic craters LRO found may have been erupting during the Cretaceous period on Earth--the heyday of dinosaurs. Some of the volcanic features may be even younger, 50 million years old, a time when mammals were replacing dinosaurs as dominant lifeforms.
"This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the Moon," says John Keller, LRO project scientist at the Goddard Space Flight Center.
IMPs are too small to be seen from Earth, averaging less than a third of a mile (500 meters) across in their largest dimension.  That's why, other than Ina, they haven't been found before.  Nevertheless, they appear to be widespread around the nearside of the Moon.
"Not only are the IMPs striking landscapes, but also they tell us something very important about the thermal evolution of the Moon," says Mark Robinson of Arizona State University, the principal investigator for LRO's high resolution camera. "The interior of the Moon is perhaps hotter than previously thought."
"We know so little of the Moon!" he continues. "The Moon is a large mysterious world in its own right, and its only three days away! I would love to land on an IMP and take the Moon's temperature first-hand using a heat probe."
Some people think the Moon looks dead, "but I never thought so," says Robinson, who won't rule out the possibility of future eruptions. "To me, it has always been an inviting place of magnificent beauty, a giant magnet in our sky drawing me towards it."
Young volcanoes have only turned up the heat on the Moon's allure. Says Robinson … "let's go!"
Credits:
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

Monday, 17 November 2014

WHERE’S ALL THE ANTIMATTER? by BRIAN KOBERLEIN on NOVEMBER 17, 2014

When we look around, everything we can see is made of matter. For every type of matter from electrons, protons and quarks there is a similar type of matter known as antimatter. So why aren’t there piles of antimatter rocks, cars and chocolate bars just lying around? Why does Scotty always have a little extra kicking around in his liquor cabinet? And where do I get mine?
The primary difference between matter and antimatter is that they have opposite electric charge. Which seems pretty mundane. The negatively charged electron has an antiparticle known as the positron, which has a positive electric charge.
Anti-protons have a negative charge, and are just flat out grumpy. We’ve been able to create these particles in the lab, and have even been able to create small amounts of anti-hydrogen consisting of a positron bound to an antiproton, when examined closely there’s were shown to have a goatee and a little colorful sash or dagger.
When we create particles in accelerators such as the Large Hadron Collider, we seem to get equal amounts of matter and antimatter. This suggests that when particles were formed soon after the big bang, there should have been equal amounts of matter and antimatter.
But the universe we observe is only made of matter, and… here’s the best part… we have no idea why. Why didn’t the matter and antimatter completely annihilate each other? How come we ended up with a little more matter? This delightful mystery is known as baryon asymmetry.
We do have a few ideas, and by we, I mean some giant brained crackerjacks have come up with a few plausible options. The most popular is that somehow antimatter behaves a little differently than matter. This could cause an imbalance between matter and antimatter. After particles collided in the early universe, there would still be matter left over, hence the matter we observe.
Another idea is that the observable universe just happens to be in a region dominated by matter. Other parts of the multiverse could have observable universes dominated by antimatter. Baryon asymmetry is one of the big mysteries of modern cosmology.
There is an even crazier idea. Antimatter might have anti-gravity. In other words, an atom of anti-hydrogen would fall up instead of down. If that is the case, then matter and antimatter would repel each other, and you might have matter universes and antimatter universes that are forever separate.There have been some initial experiments to test this idea, but so far there have been no conclusive results.

What do you think? Where’s all our antimatter and how do we track it down? I’d sure love to bring some home and show my friends

Friday, 14 November 2014

X-ray telescopes find black hole may be a neutrino factory 22 hours ago

(Phys.org) —The giant black hole at the center of the Milky Way may be producing mysterious particles called neutrinos. If confirmed, this would be the first time that scientists have traced neutrinos back to a black hole.
The evidence for this came from three NASA satellites that observe in X-ray light: the Chandra X-ray Observatory, the Swift gamma-ray mission, and the Nuclear Spectroscopic Telescope Array (NuSTAR).
Neutrinos are tiny particles that carry no charge and interact very weakly with electrons and protons. Unlike light or charged particlesneutrinos can emerge from deep within their cosmic sources and travel across the universe without being absorbed by intervening matter or, in the case of charged particles, deflected by magnetic fields.
The Earth is constantly bombarded with neutrinos from the sun. However, neutrinos from beyond the solar system can be millions or billions of times more energetic. Scientists have long been searching for the origin of ultra-high energy and very high-energy neutrinos.
"Figuring out where high-energy neutrinos come from is one of the biggest problems in astrophysics today," said Yang Bai of the University of Wisconsin in Madison, who co-authored a study about these results published in Physical Review D. "We now have the first evidence that an astronomical source – the Milky Way's supermassive black hole – may be producing these very energetic neutrinos."
Because neutrinos pass through material very easily, it is extremely difficult to build detectors that reveal exactly where the neutrino came from. The IceCube Neutrino Observatory, located under the South Pole, has detected 36 high-energy neutrinos since the facility became operational in 2010.
By pairing IceCube's capabilities with the data from the three X-ray telescopes, scientists were able to look for violent events in space that corresponded with the arrival of a high-energy neutrino here on Earth.
"We checked to see what happened after Chandra witnessed the biggest outburst ever detected from Sagittarius A*, the Milky Way's supermassive black hole," said co-author Andrea Peterson, also of the University of Wisconsin. "And less than three hours later, there was a neutrino detection at IceCube."
In addition, several neutrino detections appeared within a few days of flares from the supermassive black hole that were observed with Swift and NuSTAR.
"It would be a very big deal if we find out that Sagittarius A* produces neutrinos," said co-author Amy Barger of the University of Wisconsin. "It's a very promising lead for scientists to follow."
Scientists think that the highest energy neutrinos were created in the most powerful events in the Universe like galaxy mergers, material falling onto supermassive black holes, and the winds around dense rotating stars called pulsars.
The team of researchers is still trying to develop a case for how Sagittarius A* might produce neutrinos. One idea is that it could happen when particles around the black hole are accelerated by a shock wave, like a sonic boom, that produces charged particles that decay to neutrinos.
This latest result may also contribute to the understanding of another major puzzle in astrophysics: the source of high-energy cosmic rays. Since the charged particles that make up cosmic rays are deflected by magnetic fields in our Galaxy, scientists have been unable to pinpoint their origin. The charged particles accelerated by a shock wave near Sgr A* may be a significant source of very energetic cosmic rays.

Thursday, 6 November 2014

Breaking November 05, 2014 SCIENTISTS PROGRESS TOWARD PLASMA ACCELERATION Scientists have demonstrated the particle acceleration technique is powerful and efficient enough to drive future accelerators. 

Scientists have proven that a technique for accelerating particles on waves of plasma is efficient enough to power a new generation of shorter, more economical particle accelerators.
Using the Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC National Accelerator Laboratory, scientists from SLAC and the University of California, Los Angeles, boosted bunches of electrons to energies 400 to 500 times higher than they could have reached traveling the same distance in a conventional accelerator. They were able to transfer energy to the electrons with an unprecedented level of efficiency.
Their results, described in Nature, could eventually lead to an expansion in the use of plasma wakefield acceleration in areas such as medicine, national security, industry and high-energy physics research.
“Many of the practical aspects of an accelerator are determined by how quickly the particles can be accelerated,” says SLAC accelerator physicist Mike Litos, lead author of the paper. “To put these results in context, we have now shown that we could use this technique to accelerate an electron beam to the same energies achieved in the 2-mile-long SLAC linear accelerator, in less than 20 feet.”
Plasma wakefields have been of interest to accelerator physicists for 35 years as one of the more promising ways to drive the smaller, cheaper accelerators of the future. The UCLA and SLAC groups have been at the forefront of research on plasma wakefield acceleration for more than a decade.
In this experiment, researchers sent pairs of electron bunches containing 5 billion to 6 billion electrons each into a laser-generated column of plasma inside an oven of hot lithium gas. The first bunch in each pair blasted all the free electrons away from the lithium atoms, leaving the positively charged lithium nuclei behind—a configuration known as the “blowout regime.” The blasted electrons then fell back in behind the second bunch of electrons, forming a “plasma wake” that propelled the trailing bunch to higher energy.
Previous experiments had demonstrated multi-bunch acceleration, but the team at SLAC was the first to reach the high energies of the blowout regime, where maximum energy gains at maximum efficiencies can be found. Of equal importance, the accelerated electrons wound up with a relatively small energy spread.
“These results have an additional significance beyond a successful experiment,” says Mark Hogan, SLAC accelerator physicist and one of the principal investigators of the experiment. It “has enabled us to increase the acceleration efficiency to a maximum of 50 percent—high enough to really show that plasma wakefield acceleration is a viable technology for future accelerators.”
The plasma source used in the experiment was developed by a team of scientists led by Chandrashekhar Joshi, director of the Neptune Facility for Advanced Accelerator Research at UCLA.
“It is gratifying to see that the UCLA-SLAC collaboration on plasma wakefield acceleration continues to solve seemingly intractable problems one by one through systematic experimental work,” Joshi says. “It is this kind of transformative research that attracts the best and the brightest students to this field, and it is imperative that they have facilities such as FACET to carry it out.”
There are more milestones ahead. Before plasma wakefield acceleration can be put to use, Hogan says, the trailing bunches must be shaped and spaced just right so all the electrons in a bunch receive exactly the same boost in energy, while maintaining the high overall quality of the electron beam.
“We have our work cut out for us,” Hogan says. “But you don’t get many chances to conduct research that you know in advance has the potential to be immensely rewarding, both scientifically and practically.”

Computer simulations used in the experiments were developed by Warren Mori’s group at UCLA. Additional contributors included researchers from SLAC, the University of Oslo in Norway, Tsinghua University in China and Max Planck Institute for Physics in Germany. The research was funded by the DOE Office of Science.