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Glimpsing The Infrastructure Of A Gamma-Ray Burst Jet

December 6, 2013 Leave a comment

A new study using observations from a novel instrument provides the best look to date at magnetic fields at the heart of gamma-ray bursts, the most energetic explosions in the universe. An international team of astronomers from Britain, Slovenia and Italy has glimpsed the infrastructure of a burst’s high-speed jet.

Gamma-ray bursts are the most luminous explosions in the cosmos. Most are 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.

On March 8, 2012, NASA’s Swift satellite detected a 100-second pulse of gamma rays from a source in the constellation Ursa Minor. The spacecraft immediately forwarded the location of the gamma-ray burst, dubbed GRB 120308A, to observatories around the globe.

The world’s largest fully autonomous robotic optical telescope, the 2-meter Liverpool Telescope located at Roque de los Muchachos Observatory on La Palma in the Canary Islands, automatically responded to Swift’s notification.

“Just four minutes after it received Swift’s trigger, the telescope found the burst’s visible afterglow and began making thousands of measurements,” said lead researcher Carole Mundell, who heads the gamma-ray burst team at the Astrophysics Research Institute at Liverpool John Moores University in the U.K.

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Fledgling Supernova Remnant Reveals Neutron Star’s Secrets

December 6, 2013 1 comment

Image: X-ray: NASA/CXC/UW-Madison/S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA

Image: X-ray: NASA/CXC/UW-Madison/S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA

With the help of NASA’s Chandra X-ray Observatory and the Australia Telescope Compact Array, an international team of astronomers has identified the glowing wreck of a star that exploded a mere 2,500 years ago — the blink of an eye in astronomical terms.

The observations, made by a team led by UW-Madison astronomy professor Sebastian Heinz, reveal an astrophysical novelty of the Milky Way: a glowing nebula created when the star exploded and, inside of it, the collapsed core of the exploded star, a neutron star, still clinging to its former companion star. It is the only known example of such a system in our galaxy.

The new observations are reported Dec. 3 in the Astrophysical Journal and are important because they provide a unique laboratory to test key theories of stellar evolution, especially about the stage of a star’s life just after most of it has been obliterated in a supernova explosion.

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You Can’t Get Entangled Without A Wormhole

December 6, 2013 Leave a comment

Quantum entanglement is one of the more bizarre theories to come out of the study of quantum mechanics — so strange, in fact, that Albert Einstein famously referred to it as “spooky action at a distance.”

Essentially, entanglement involves two particles, each occupying multiple states at once — a condition referred to as superposition. For example, both particles may simultaneously spin clockwise and counterclockwise. But neither has a definite state until one is measured, causing the other particle to instantly assume a corresponding state. The resulting correlations between the particles are preserved, even if they reside on opposite ends of the universe.

But what enables particles to communicate instantaneously — and seemingly faster than the speed of light — over such vast distances? Earlier this year, physicists proposed an answer in the form of “wormholes,” or gravitational tunnels. The group showed that by creating two entangled black holes, then pulling them apart, they formed a wormhole — essentially a “shortcut” through the universe — connecting the distant black holes.

Now an MIT physicist has found that, looked at through the lens of string theory, the creation of two entangled quarks — the building blocks of matter — simultaneously gives rise to a wormhole connecting the pair.

The theoretical results bolster the relatively new and exciting idea that the laws of gravity holding together the universe may not be fundamental, but arise from something else: quantum entanglement.

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Martian Laser Surpasses 100,000 Zaps

December 6, 2013 1 comment

The ChemCam laser instrument aboard NASA’s Curiosity rover fired its 100,000th shot recently, chronicling its adventures on Mars with a coffee-table-book’s worth of spectral data that might rival snapshots gathered during a long and satisfying family vacation here on Earth. ChemCam zaps rocks with a high-powered laser to determine their composition and carries a camera that can survey the Martian landscape.

“ChemCam has greatly exceeded our expectations,” said Roger Wiens, Los Alamos National Laboratory planetary scientist and Principal Investigator of the ChemCam Team. “The information we’ve gleaned from the instrument will continue to enhance our understanding of the Red Planet, and will nicely complement information from the other nine instruments aboard Curiosity as we continue our odyssey to Mount Sharp.”

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