A major revision is required in our understanding of our Milky Way Galaxy according to an international team led by Prof Noriyuki Matsunaga of the University of Tokyo. The Japanese, South African and Italian astronomers find that there is a huge region around the center of our own Galaxy, which is devoid of young stars.

The Milky Way is a spiral galaxy containing many billions of stars with our Sun about 26,000 light years from its centre. Measuring the distribution of these stars is crucial to our understanding of how our Galaxy formed and evolved. Pulsating stars called Cepheids are ideal for this. They are much younger (between 10 and 300 million years old) than our Sun (4.6 billion years old) and they pulsate in brightness in a regular cycle. The length of this cycle is related to the luminosity of the Cepheid, so if astronomers monitor them they can establish how bright the star really is, compare it with what we see from Earth, and work out its distance.

The artist's impression below shows the implied distribution of young stars, represented here by Cepheids shown as blue stars, plotted on the background of a drawing of the Milky Way.

Despite this, finding Cepheids in the inner Milky Way is difficult, as the Galaxy is full of interstellar dust which blocks out light and hides many stars from view. Matsunaga's team compensated for this, with an analysis of near-infrared observations made with a Japanese-South African telescope located at Sutherland, South Africa. To their surprise they found hardly any Cepheids in a huge region stretching for thousands of light years from the core of the Galaxy.

Noriyuki Matsunaga explains: "We already found some while ago that there are Cepheids in the central heart of our Milky Way (in a region about 150 light years in radius). Now we find that outside this there is a huge Cepheid desert extending out to 8000 light years from the center."

This suggests that a large part of our Galaxy, called the Extreme Inner Disk, has no young stars. Co-author Michael Feast notes: "Our conclusions are contrary to other recent work, but in line with the work of radio astronomers who see no new stars being born in this desert."

Another author, Giuseppe Bono, points out: "The current results indicate that there has been no significant star formation in this large region over hundreds of millions years. The movement and the chemical composition of the new Cepheids are helping us to better understand the formation and evolution of the Milky Way."

Cepheids have more typically been used to measure the distances of objects in the distant Universe, and the new work is an example instead of the same technique revealing the structure of our own Milky Way.

The team publish their work in a paper in Monthly Notices of the Royal Astronomical Society.

The Daily Galaxy via The University of Tokyo

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China is planning to build an enormous particle accelerator twice the size and seven times as powerful as CERN's Large Hadron Collider, according to state media reports. According to China Daily, the new facility will be capable of producing millions of Higgs boson particles - a great deal more than the Large Hadron Collider which originally discovered the ‘God particle' back in 2012. 

"We have completed the initial conceptual design and organized international peer review recently, and the final conceptual design will be completed by the end of 2016," Wang Yifang, director of the Institute of High Energy Physics, Chinese Academy of Sciences, told China Daily in an exclusive interview.

The institute has been operating major high-energy physics projects in China, such as the Beijing Electron Positron Collider and the Daya Bay Reactor Neutrino experiment. Now scientists are proposing a more ambitious new accelerator with seven times the energy level of the Large Hadron Collider in Europe. The first phase of the project's construction is scheduled to begin between 2020 and 2025.

“So far the Standard Model seems to explain matter, but we know there has to be something beyond the Standard Model,” said Denise Caldwell, director of the Physics Division of the National Science Foundation. “This potential new physics can only be uncovered with more data that will come with the next LHC run.”

The Standard Model contains no explanation of gravity, which is one of the four fundamental forces in the universe. It also does not explain astronomical observations of dark matter, a type of matter that interacts with our visible universe only through gravity, nor does it explain why matter prevailed over antimatter during the formation of the early universe. The small mass of the Higgs boson also suggests that matter is fundamentally unstable.

Gerald Hooft, winner of the Nobel Prize in Physics, said in an interview to Doha-based broadcaster Al Jazeera that China's proposed collider, if built, "will bring hundreds, probably thousands, of top class scientists with different specializations, from pure theory to experimental physics and engineering, from abroad to China". Chinese scientists have completed an initial conceptual design of a super giant particle collider which will be bigger and more powerful than any particle accelerator on Earth.

In July 2012, the European Organization for Nuclear Research, also known as CERN, announced that it had discovered the long sought-after Higgs boson－the "God particle", regarded as the crucial link that could explain why other elementary particles have mass－on LHC. The discovery was believed to be one of the most important in physics for decades. Scientists are hopeful that it will further explain nature and the universe we live in.

The high-energy frontier has traditionally had one primary goal, to probe directly any uncharted physics waters. This has translated into the gigantic effort to complete the unobserved elements of the Standard Model of particle physics as well as to search for for signs of physics beyond.These measurements form a solid base from which searches for physics beyond the standard model have been launched. Since the discovery of the Higgs in 2012, searches for supersymmetry and several signatures of possible new exotic physics phenomena have been developed, and new parameter space is being explored.

In 2016, the Large Hadron Collider, the world's most powerful proton smasher, is preparing for its biggest run yet which scientists hope will uncover new particles that could dramatically change our understanding of the Universe. Scientists had been gearing up to resume experiments at the LHC this week, but the plans were delayed after a weasel wandered onto a high-voltage electrical transformer last Friday, causing a short-circuit. CERN told AFP that experiments were now expected to get underway next week.

The LHC, housed in a 27-kilometre (17-mile) tunnel straddling the French-Swiss border, has shaken up physics before. In 2012 it was used to prove the existence of the Higgs Boson -- the long-sought maker of mass -- by crashing high-energy proton beams at velocities near the speed of light. (A proton-lead ion collision, shown below as observed by the LHCb detector during the 2013 data-taking period LHCb/CERN). The giant lab might prove the exotic theory of supersymmetry, SUSY for short, which suggests the existence of a heavier "sibling" for every particle in the universe. The unexpected excess pair of photons spotted last year could be a larger cousin of the Higgs, according to one theory.

While LHC is composed of 27-kilometer-long accelerator chains and detectors buried 100 meters underground at the border of Switzerland and France, scientists only managed to spot hundreds of Higgs boson particles, not enough to learn the structure and other features of the particle.

With a circumference of 50 to 100 km, however, the proposed Chinese accelerator Circular Electron Positron Collider (CEPC) will generate millions of Higgs boson particles, allowing a more precise understanding.

"The technical route we chose is different from LHC. While LHC smashes together protons, it generates Higgs particles together with many other particles," Wang said. "The proposed CEPC, however, collides electrons and positrons to create an extremely clean environment that only produces Higgs particles," he added.

The Higgs boson factory is only the first step of the ambitious plan. A second-phase project named SPPC (Super Proton-Proton Collider) is also included in the design－a fully upgraded version of LHC.

LHC shut down for upgrading in early 2013 and restarted in June with an almost doubled energy level of 13 TeV, a measurement of electron volts.

"LHC is hitting its limits of energy level, it seems not possible to escalate the energy dramatically at the existing facility," Wang said. The proposed SPPC will be a 100 TeV proton-proton collider.

If everything moves forward as proposed, the construction of the first phase project CEPC will start between 2020 and 2025, followed by the second phase in 2040.

"China brings to this entire discussion a certain level of newness. They are going to need help, but they have financial muscle and they have ambition," said Nima Arkani Hamed from the Institute for Advanced Study in the United States, who joined the force to promote CEPC in the world.

David J. Gross, a US particle physicist and 2004 Nobel Prize winner, wrote in a commentary co-signed by US theoretical physicist Edward Witten that although the cost of the project would be great, the benefits would also be great. "China would leap to a leadership position in an important frontier area of basic science," he wrote.

Today's Most Popular

The Daily Galaxy via China Daily

Image credit: CERN

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The universe is 13.8 billion years old, while our planet formed just 4.5 billion years ago. Some scientists think this time gap means that life on other planets could be billions of years older than ours. However, new theoretical work suggests that present-day life is actually premature from a cosmic perspective.

"If you ask, 'When is life most likely to emerge?' you might naively say, 'Now,'" says lead author Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. "But we find that the chance of life grows much higher in the distant future."

Life as we know it first became possible about 30 million years after the Big Bang, when the first stars seeded the cosmos with the necessary elements like carbon and oxygen. Life will end 10 trillion years from now when the last stars fade away and die. Loeb and his colleagues considered the relative likelihood of life between those two boundaries.

The dominant factor proved to be the lifetimes of stars. The higher a star's mass, the shorter its lifetime. Stars larger than about three times the sun's mass will expire before life has a chance to evolve.

Conversely, the smallest stars weigh less than 10 percent as much as the Sun. They will glow for 10 trillion years, giving life ample time to emerge on any planets they host. As a result, the probability of life grows over time. In fact, chances of life are 1000 times higher in the distant future than now.

"So then you may ask, why aren't we living in the future next to a low-mass star?" says Loeb. "One possibility is we're premature. Another possibility is that the environment around a low-mass star is hazardous to life."

Although low-mass, red dwarf stars live for a long time, they also pose unique threats. In their youth they emit strong flares and ultraviolet radiation that could strip the atmosphere from any rocky world in the habitable zone.

To determine which possibility is correct -- our premature existence or the hazard of low-mass stars -- Loeb recommends studying nearby red dwarf stars and their planets for signs of habitability. Future space missions like the Transiting Exoplanet Survey Satellite and James Webb Space Telescope should help to answer these questions.

 The Daily Galaxy via CfA

Image credit: With thanks to insider.si.edu and 3tags,org

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Atmospheric temperatures on Jupiter range from around 1,700 degrees Fahrenheit to upward of 2,420 degrees. That's greater than the temperature of molten lava and would cause lithium batteries in cellphones to boil and turn to gas. These wide ranges in temperature could not just be explained by heat from the sun, said James O'Donoghue, a research scientist at Boston University's Center for Space Physics.

Researchers from Boston University's (BU) Center for Space Physics report today in Nature that Jupiter's Great Red Spot may provide the mysterious source of energy required to heat the planet's upper atmosphere to the unusually high values observed.

Sunlight reaching Earth efficiently heats the terrestrial atmosphere at altitudes well above the surfaceeven at 250 miles high, for example, where the International Space Station orbits. Jupiter is over five times more distant from the Sun, and yet its upper atmosphere has temperatures, on average, comparable to those found at Earth. The sources of the non-solar energy responsible for this extra heating have remained elusive to scientists studying processes in the outer solar system.

“With solar heating from above ruled out, we designed observations to map the heat distribution over the entire planet in search for any temperature anomalies that might yield clues as to where the energy is coming from,” explained Dr. James O'Donoghue, research scientist at BU, and lead author of the study.

Astronomers measure the temperature of a planet by observing the non-visible, infrared (IR) light it emits. The visible cloud tops we see at Jupiter are about 30 miles above its rim; the IR emissions used by the BU team came from heights about 500 miles higher. When the BU observers looked at their results, they found high altitude temperatures much larger than anticipated whenever their telescope looked at certain latitudes and longitudes in the planet's southern hemi-sphere.

Jupiter's Great Red Spot (GRS) is one of the marvels of our solar system. Discovered within years of Galileo's introduction of telescopic astronomy in the 17th Century, its swirling pattern of colorful gases is often called a “perpetual hurricane.” The GRS has varied is size and color over the centuries, spans a distance equal to three earth-diameters, and has winds that take six days to complete one spin. Jupiter itself spins very quickly, completing one revolution in only ten hours.

“The Great Red Spot is a terrific source of energy to heat the upper atmosphere at Jupiter, but we had no prior evidence of its actual effects upon observed temperatures at high altitudes,” ex-plained Dr. Luke Moore, a study co-author and research scientist in the Center for Space Physics at BU.

Solving an “energy crisis” on a distant planet has implications within our solar system, as well as for planets orbiting other stars. As the BU scientists point out, the unusually high temperatures far above Jupiter's visible disk is not a unique aspect of our solar system. The dilemma also occurs at Saturn, Uranus and Neptune, and probably for all giant exoplanets outside our solar system.

“Energy transfer to the upper atmosphere from below has been simulated for planetary atmospheres, but not yet backed up by observations,” O'Donoghue said. “The extremely high temperatures observed above the storm appear to be the ‘smoking gun' of this energy transfer, indicating that planet-wide heating is a plausible explanation for the ‘energy crisis.'”

The Daily Galaxy via Boston University

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In the first few minutes following “the big bang,” the universe quickly began expanding and cooling, allowing the formation of subatomic particles that joined forces to become protons and neutrons. These particles then began interacting with one another to create the first simple atoms. A little more time, a little more expansion, a lot more cooling—along with ever-present gravitational pull—and clouds of these elements began to morph into stars and galaxies.

For William Detmold, an assistant professor of physics at MIT who uses lattice quantum chromodynamics (LQCD) to study subatomic particles, one of the most interesting aspects of the formation of the early universe is what happened in those first few minutes—a period known as the “big bang nucleosynthesis.”

“You start off with very high-energy particles that cool down as the universe expands, and eventually you are left with a soup of quarks and gluons, which are strongly interacting particles, and they form into protons and neutrons,” he said. “Once you have protons and neutrons, the next stage is for those protons and neutrons to come together and start making more complicated things—primarily deuterons, which interact with other neutrons and protons and start forming heavier elements, such as Helium-4, the alpha particle.”

One of the most critical aspects of big bang nucleosynthesis is the radiative capture process, in which a proton captures a neutron and fuses to produce a deuteron and a photon. In a paper published in Physical Review Letters, Detmold and his co-authors—all members of the NPLQCD Collaboration, which studies the properties, structures and interactions of fundamental particles—describe how they used LQCD calculations to better understand this process and precisely measure the nuclear reaction rate that occurs when a neutron and proton form a deuteron. While physicists have been able to experimentally measure these phenomena in the laboratory, they haven't been able to do the same, with certainty, using calculations alone—until now.

“One of the things that is very interesting about the strong interaction that takes place in the radiative capture process is that you get very complicated structures forming, not just protons and neutrons,” Detmold said. “The strong interaction has this ability to have these very different structures coming out of it, and if these primordial reactions didn't happen the way they happened, we wouldn't have formed enough deuterium to form enough helium that then goes ahead and forms carbon. And if we don't have carbon, we don't have life.”

For the Physical Review Letters paper, the team used the Chroma LQCD code developed at Jefferson Lab to run a series of calculations with quark masses that were 10-20 times the physical value of those masses. Using heavier values rather than the actual physical values reduced the cost of the calculations tremendously, Detmold noted. They then used their understanding of how the calculations should depend on mass to get to the physical value of the quark mass.

“When we do an LQCD calculation, we have to tell the computer what the masses of the quarks we want to work with are, and if we use the values that the quark masses have in nature it is very computationally expensive,” he explained. “For simple things like calculating the mass of the proton, we just put in the physical values of the quark masses and go from there. But this reaction is much more complicated, so we can't currently do the entire thing using the actual physical values of the quark masses.

While this is the first LQCD calculation of an inelastic nuclear reaction, Detmold is particularly excited by the fact that being able to reproduce this process through calculations means researchers can now calculate other things that are similar but that haven't been measured as precisely experimentally—such as the proton-proton fusion process that powers the sun—or measured at all.

“The rate of the radiative capture reaction, which is really what we are calculating here, is very, very close to the experimentally measured one, which shows that we actually understand pretty well how to do this calculation, and we've now done it, and it is consistent with what is experimentally known,” Detmold said. “This opens up a whole range of possibilities for other nuclear interactions that we can try and calculate where we don't know what the answer is because we haven't, or can't, measure them experimentally. Until this calculation, I think it is fair to say that most people were wary of thinking you could go from quark and gluon degrees of freedom to doing nuclear reactions. This research demonstrates that yes, we can.”

The Daily Galaxy via https://www.nersc.gov/news

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"There is a powerful analogy between the Earth's first mass extinction and what is happening today," said Simon Darroch, at Vanderbilt University. "The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and today we humans are the most powerful 'ecosystems engineers' ever known."

Newly discovered fossil evidence from Namibia strengthens the proposition that the world's first mass extinction was caused by "ecosystem engineers" - newly evolved biological organisms that altered the environment so radically it drove older species to extinction. The event, known as the end-Ediacaran extinction, took place 540 million years ago. The earliest life on Earth consisted of microbes - various types of single-celled organisms. These held sway for more than 3 billion years, when the first multicellular organisms evolved. The most successful of these were the Ediacarans, which spread around the globe about 600 million years ago. They were a largely immobile form of marine life shaped like discs and tubes, fronds and quilted mattresses.

After 60 million years, evolution gave birth to another major innovation: metazoans, the first animals. Metazoans could move spontaneously and independently at least during some point in their life cycle and sustain themselves by eating other organisms or what other organisms produce. Animals burst onto the scene in a frenzy of diversification that paleontologists have labeled the Cambrian explosion, a 25 million-year period when most of the modern animal families - vertebrates, mollusks, arthropods, annelids, sponges and jellyfish - came into being.

"These new species were 'ecological engineers' who changed the environment in ways that made it more and more difficult for the Ediacarans to survive," said Darroch, assistant professor of earth and environmental sciences, who directed the new study.

Darroch and his colleagues report that they have found one of the best-preserved examples of a mixed community of Ediacarans and animals, which provides the best evidence of a close ecological association between the two groups.

"Until this, the evidence for an overlapping ecological association between metazoans and soft-bodied Ediacaran organisms was limited," Darroch said. "Here, we describe new fossil localities from southern Namibia that preserve soft-bodied Ediacara biota, enigmatic tubular organisms thought to represent metazoans and vertically oriented metazoan trace fossils. Although the precise identity of the tracemakers remains elusive, the structures bear several striking similarities with a cone-shaped organism called Conichnus that has been found in the Cambrian period."

In a previous paper that Darroch and his collaborators published last September, they reported on a fossil record that showed stressed-looking communities of Ediacara associated with a suite of animal burrows.

"With this paper we're narrowing in on causation; we've discovered some new fossil sites that preserve both Ediacara biota and animal fossils (both animal burrows - 'trace fossils' - and the remains of animals themselves) sharing the same communities, which lets us speculate about how these two very different groups of organisms interacted," he said.

Conichnus burrows are trace fossils: the surface bumps shown below represent vertical tubes that were originally occupied by anemone-like animals that may have fed on Ediacaran larvae.

"Some of the burrow fossils we've found are usually interpreted as being formed by sea anemones, which are passive predators that may have preyed upon Ediacaran larvae. We've also found stands of Ediacaran frondose organisms, with animal fossils preserved in place coiled around their bases. In general, these new fossil sites reveal a snapshot of a very unusual 'transitional' ecosystem existing right before the Cambrian explosion, with the last of the Ediacara biota clinging on for grim death, just as modern-looking animals are diversifying and starting to realize their potential."

The Daily Galaxy via Vanderbilt University

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This artist's conception shows a red dwarf star orbited by a pair of habitable planets. Because red dwarf stars live so long, the probability of cosmic life grows over time. As a result, Earthly life might be considered “premature.” (Image by Christine Pulliam/CfA)