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POPSNew Exotic Particle May Explain Milky Way Gamma Phenomenon So what produces gamma-rays in large numbers? The first thing that comes to mind is a gamma-ray burst, produced when a massive star dies and collapses as a supernova. But this is short-lived and not sustained. How about the supermassive black hole sitting in the middle of the Milky Way’s galactic nucleus? This theory was recently discussed on Astroengine, but the production of antimatter (i.e. positrons) is more of a slow leak than anything substantial, certainly not of the scale that is being measured. As we are dealing with gamma-rays of the exact rest mass energy as a positron, so we know that the source is some kind of positron annihillation. What could possibly be doing this?
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POPSQuiet Explosion: Object Intermediate Between Normal Supernovae And Gamma-ray Bursts Found Stars that were at birth more massive than about 8 times the mass of our Sun end their relatively short life in a cosmic, cataclysmic firework lighting up the Universe. The outcome is the formation of the densest objects that exist, neutron stars and black holes. When exploding, some of the most massive stars emit a short cry of agony, in the form of a burst of very energetic light, X- or gamma-rays.
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POPSEchoes of a Supernova: Spitzer Space Telescope We can't physically travel back in time (yet?) but the complete history of the universe lays before our eyes. As our technology, and understanding improves, what we can read of that history also improves, continually answering questions that we had not dreamed of just a short time ago.
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POPSA Quark Star? Super-luminous Stellar Explosion Observed Quarks are the fundamental components of protons and neutrons, which make up the nucleus of atoms. The most dense objects known to exist today are neutron stars--stars composed entirely of tightly packed neutrons. A typical neutron star is some 16 miles across, yet has a mass one and a half times the mass of our Sun. The question is, is a neutron star indeed the most dense object that exists? It is thought that if the neutrons are too tightly packed--if what scientists consider a neutron star is too dense--the resulting instability may lead to a further collapse, resulting in a second explosion and the creation of a quark star. The energy that powers that second explosion comes from neutrons breaking down into their component parts: quarks.
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POPSBored With Web 2.0? Demand Change This manifesto for change comes at an important time, when a recent, but growing trend of Web 2.0 ennui is beginning to strike the citizens of the social media landscape. Even VC Fred Wilson was recently caught wondering if he was "bored with Web 2.0," saying: But I am a bit jealous of friends who are working on finding and funding alternative energy or biomedical technologies that have the potential to address the serious problems facing the world. At times it seems that helping the web become more social, intelligent, mobile, and playful is not as impactful.
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POPSFamous supernovae still echo across the Milky Way Read to understand pic. In 1572, the Danish astronomer Tycho Brahe observed and studied the explosion of a star that became known as Tycho's supernova. More than four centuries later, Chandra's X-ray photograph of the supernova remnant shows an expanding bubble of multimillion degree debris (green and red) inside a more rapidly moving shell of extremely high energy electrons (filamentary blue). Astronomers have detected a light echo from this supernova, meaning they can see the light from the explosion itself 400 years later.
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POPSExploding star caught in the act Astronomers for years have been wondering if they'd ever see a 'live' supernova. They're few, quick, and you have to be looking in the right place at the right time. Seems they were. One of those things that may not happen again in our lifetimes - but you never know.
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POPSYoungest Exploded Star In The Milky Way Is Discovered
It turns out, Green and his team came across the remnants, now called G1.9+0.3, more than 20 years ago using the Very Large Array (VLA) radio telescope in Socorro, NM, and estimated the object’s age to be 400-1,000 years old. It is near the center of the Milky Way, some 25,000 light-years from Earth. By comparing notes, the astronomers learned the images taken more than two decades apart documented the expansion of debris from the star's explosion. The images taken in 2007 were about 16 percent larger than the ones taken in 1985. "This is a huge difference," said Reynolds. "It means the explosion debris is expanding very quickly, which in turn means the object is much younger than we originally thought." Reynolds also observed the object with the VLA radio telescope to confirm the supernova remnant's rapid expansion. Unlike visible-light telescopes, radio and X-ray telescopes can penetrate the thick clouds of gas and dust in our galaxy.
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