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Showing posts with label Electronvolt. Show all posts
Showing posts with label Electronvolt. Show all posts

Saturday, November 23, 2013

Discovery Of Cosmic Neutrinos Signals New Era Of Astronomy

November 21, 2013

Computers at the IceCube laboratory collect raw data in near-real time from detectors buried deep in the Antarctic ice.
Credit: Felipe Pedreros, IceCube/NSF
Lee Rannals for redOrbit.com – Your Universe Online

Astronomers working with the IceCube Neutrino Observatory in Antarctica have announced that they have, for the first time, observed 28 very high-energy particle events, leading them to conclude that “the era of neutrino astronomy has begun.”

Cosmic neutrinos are nearly massless particles that stream to Earth at the speed of light from outside our solar system. This observation, published in the journal Science, will allow scientists to learn about the nature of astrophysical phenomena that occurs millions to billions of light years away from Earth.

“The sources of neutrinos, and the question of what could accelerate these particles, has been a mystery for more than 100 years. Now we have an instrument that can detect astrophysical neutrinos. It’s working beautifully, and we expect it to run for another 20 years,” Gregory Sullivan, who led the team from University of Maryland, said in a statement.

Between May 2010 and May 2012, the IceCube detector at the South Pole captured a total of 28 neutrinos with energies greater than 30 teraelectronvolts (TeV). Two of the neutrinos had an energy of more than 1,000 TeV, which is more than the kinetic energy of a flying bug.

“This is the first indication of very high-energy neutrinos coming from outside our solar system,” said Francis Halzen, principal investigator of IceCube and the Hilldale and Gregory Breit Distinguished Professor of Physics at the University of Wisconsin-Madison.

Continue Learning: http://www.redorbit.com/news/space/1113010258/icecube-cosmic-neutrino-discovery-astronomy-112113/

Friday, November 22, 2013

NASA sees 'watershed' cosmic blast in unique detail

Posted: Nov 21, 2013 by Francis Reddy

In the most common type of gamma-ray burst, illustrated here, a dying massive star forms a
black hole (left), which drives a particle jet into space.
Credit: NASA's Goddard Space Flight Center
(Phys.org) —On April 27, a blast of light from a dying star in a distant galaxy became the focus of astronomers around the world. The explosion, known as a gamma-ray burst and designated GRB 130427A, tops the charts as one of the brightest ever seen

A trio of NASA satellites, working in concert with ground-based robotic telescopes, captured never-before-seen details that challenge current theoretical understandings of how gamma-ray bursts work.

"We expect to see an event like this only once or twice a century, so we're fortunate it happened when we had the appropriate collection of sensitive space telescopes with complementary capabilities available to see it," said Paul Hertz, director of NASA's Astrophysics Division in Washington.

Gamma-ray bursts are the most luminous explosions in the cosmos, thought to be triggered when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star and erupt into space at nearly the speed of light.

Gamma-rays are the most energetic form of light. Hot matter surrounding a new black hole and internal shock waves produced by collisions within the jet are thought to emit gamma-rays with energies in the million-electron-volt (MeV) range, or roughly 500,000 times the energy of visible light. The most energetic emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when the jet slams into its surroundings, forming an external shock wave.

The Gamma-ray Burst Monitor (GBM) aboard NASA's Fermi Gamma-ray Space Telescope captured the initial wave of gamma rays from GRB 130427A shortly after 3:47 a.m. EDT April 27. In its first three seconds alone, the "monster burst" proved brighter than almost any burst previously observed.

Continue Learning: http://phys.org/news/2013-11-nasa-watershed-cosmic-blast-unique.html
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