This week we have some great news from particle physicists working with the Telescope Array in the desert at Utah, astrophysicists from the Institute for Space Astrophysics and Planetology in Rome and physicists and Stanford University. As always, the top 3 news stories are summarized below. For more news check out our news section.
For decades physicists have been hunting for the source of the most energetic subatomic particles: the cosmic rays, which strike the atmosphere with huge energies. Recently, a team of working with the Telescope Array, a collection of 507 particle detectors covering 700 square kilometers of desert in Utah, has observed a broad “hotspot” in the sky in which such cosmic rays seem to originate.
Nobody knows how ultra–high-energy cosmic rays—mainly protons or heavier atomic nuclei—acquire energies millions of times higher than have been achieved with humanmade particle accelerators. The Telescope Array aims to help solve that mystery. From 2008 to 2013, researchers spotted 72 cosmic rays with energies above 57 exaelectron volts—15 million times the highest energy achieved with a particle accelerator.19 of them appear to cluster in a hotspot in the sky about 20° in radius, as Hiroyuki Sagawa, a co-representative for the Telescope Array team from the University of Tokyo, reported.
Scientists at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory have found a way to estimate uncertainties in computer calculations that are widely used to speed the search for new materials for industry, electronics, energy, drug design and a host of other applications.
“Over the past 10 years our ability to calculate the properties of materials and chemicals, such as reactivity and mechanical strength, has increased enormously. It’s totally exploded,” said Jens Nørskov, a professor at SLAC and Stanford and director of the SUNCAT Center for Interface Science and Catalysis, who led the research.
“As more and more researchers use computer simulations to predict which materials have the interesting properties we’re looking for – part of a process called ‘materials by design’—knowing the probability for error in these calculations is essential,” he said. “It tells us exactly how much confidence we can put in our results.”
So recently astronomers analyzing a long-lasting blast of high-energy light observed in 2013 report finding features strikingly similar to those expected from an explosion from the universe’s earliest stars.
“One of the great challenges of modern astrophysics has been the quest to identify the first generation of stars to form in the universe, which we refer to as Population III stars,” explained lead scientist Luigi Piro, the director of research at the Institute for Space Astrophysics and Planetology in Rome. “This important event takes us one step closer.”
The observed gamma ray burst is special: “GRB 130925A is a member of a rare and newly recognized class we call ultra-long bursts,” said Eleonora Troja, a visiting research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a member of the study team. “But what really sets it apart is its unusual X-ray afterglow, which provides the strongest case yet that ultra-long GRBs come from stars called blue supergiants.”