Oldest Recorded Supernova
NASA – This image combines data from four space telescopes to create a multi-wavelength view of all that remains of RCW 86, the oldest documented example of a supernova. Chinese astronomers witnessed the event in 185 A.D., documenting a mysterious “guest star” that remained in the sky for eight months. X-ray images from NASA’s Chandra X-ray Observatory and the European Space Agency‘s XMM-Newton Observatory were combined to form the blue and green colors in the image. The X-rays show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova.
Infrared data from NASA’s Spitzer Space Telescope and WISE, Wide-Field Infrared Survey Explorer, shown in yellow and red, reveal dust radiating at a temperature of several hundred degrees below zero, warm by comparison to normal dust in our Milky Way galaxy.
By studying the X-ray and infrared data, astronomers were able to determine that the cause of the explosion was a Type Ia supernova, in which an otherwise-stable white dwarf, or dead star, was pushed beyond the brink of stability when a companion star dumped material onto it. Furthermore, scientists used the data to solve another mystery surrounding the remnant — how it got to be so large in such a short amount of time. By blowing away wind prior to exploding, the white dwarf was able to clear out a huge “cavity,” a region of very low-density surrounding the system. The explosion into this cavity was able to expand much faster than it otherwise would have.
This is the first time that this type of cavity has been seen around a white dwarf system prior to explosion. Scientists say the results may have significant implications for theories of white-dwarf binary systems and Type Ia supernovae.
RCW 86 is approximately 8,000 light-years away. At about 85 light-years in diameter, it occupies a region of the sky in the southern constellation of Circinus that is slightly larger than the full moon. This image was compiled in October 2011. Image Credit: X-ray: NASA/CXC/SAO & ESA; Infared: NASA/JPL-Caltech/B. Williams (NCSU)
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Posted in Nature, Science, SPACE WATCH
Tagged Chandra X-ray Observatory, European Space Agency, NASA, RCW Catalogue, Space, Spitzer Space Telescope, Type Ia supernova, Wide-field Infrared Survey Explorer, XMM-Newton
By Maria Margaronis – As I write, the Greek parliament is preparing to vote on the bond swap agreed with the country’s private creditors and on the new deal with the EU and the IMF, which would lend the country €130bn in exchange for cuts that slice the last little bits of flesh from the economy – including a 22% reduction in the minimum wage and 150,000 public sector job losses by 2016. Without the deal, Greece will default by March; with it, the country will sink into a still deeper depression, with no end in sight. more> http://is.gd/LLz3o1
Posted in Banking, Economy, Leadership
Tagged Austerity, Deficit, European Union, Financial crisis, Government, Greece, Hellenic Parliament, International Monetary Fund, Minimum wage, Public sector
By Michael Geist – When the CRTC conducted hearings on Internet traffic management practices in the summer of 2009, most Internet providers used traffic shaping technologies to limit peer-to-peer applications arguing that it was necessary to manage subscriber demands and to avoid network congestion.
The CRTC rejected that advice and implemented guidelines that required Internet providers to publicly disclose their traffic management practices. Moreover, it established rules that require providers to respond to complaints by describing their practices, demonstrating their necessity, and establishing that they discriminate as little as possible.
Not much changed during the first two years. Over the past six months, however, the commission has prioritized the enforcement issue and when combined with changing Internet usage patterns and several dogged complainants, traffic shaping in Canada is about to disappear from the Internet landscape. more> http://is.gd/n3DWsN
Posted in Broadband, Net, net neutrality
Tagged Broadband, Canada, Canadian Radio-television and Telecommunications Commission, CRTC, Internet, Internet service provider, Internet traffic, Michael Geist, Traffic shaping
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