![]() The smoking gun for neutrino mass is evidence of neutrino oscillations, in which one of the three flavors of neutrino transforms into another as it propagates. Since 1998, we have known that the neutrino is massive, in contradiction with the assumptions of the standard model of particle physics. Based on just one month’s worth of data, the Collaboration puts an upper limit of 1.1 eV on the neutrino mass, improving by a factor of 2 the mass limits derived by previous measurements that directly characterized the particle mass. After almost two decades of planning and preparation, the Karlsruhe Tritium Neutrino (KATRIN) Collaboration in Germany announces its first results. And since neutrinos are the most abundant massive particles in the Universe, the value of their mass would be important for cosmological models, influencing the formation of large-scale cosmic structures. Understanding what gives the neutrino a mass could help scientists pinpoint new physics beyond the standard model. Even its most basic property-its mass-is still unknown. The neutrino remains a truly mysterious particle, despite intense scientific efforts that have lasted for many decades. Approximately 80,000 people are killed as a direct result of the blast, and another 35,000 are injured.KATRIN Figure 1: Photograph of the electron spectrometer used by KATRIN. The United States On August 6, 1945, the United States becomes the first and only nation to use atomic weaponry during wartime when it drops an atomic bomb on the Japanese city of Hiroshima. ![]() Is there still radiation in Hiroshima and Nagasaki? The radiation in Hiroshima and Nagasaki today is on a par with the extremely low levels of background radiation (natural radioactivity) present anywhere on Earth. The new model showed that a non-interacting or sterile neutrino is probably a dark matter particle and contributes to the mass of dark matter. Last September, an experiment called OPERA turned up evidence that neutrinos travel faster than the speed of light (see 'Particles break light speed limit'). Neutrinos are tiny, electrically neutral particles produced in nuclear reactions. To “see” them, we have to build really big detectors and block out signals from any other particles. But unlike the sunlight we can easily see, neutrinos are very hard to detect. Billions of them pass through us every second-mostly coming from our sun. The neutron bomb was tested successfully in 1962, but to Cohen's dismay, there were few takers for it. Since the neutron bomb produced little or no radioactive fallout or residual radiation, the target area could be reoccupied within a matter of hours. Does the US have a neutron bomb?Īlthough the United States has manufactured and stockpiled neutron bombs, in order to mollify public opposition in Europe it announced in 1981 that these weapons would not be deployed overseas at that time. The thermal pulse would cause third degree burns to unprotected skin out to approximately 500 meters. Upon detonation, a near-ground airburst of a 1 kiloton neutron bomb would produce a large blast wave and a powerful pulse of both thermal radiation and ionizing radiation in the form of fast (14.1 MeV) neutrons. If it was ever built, a state could use the device to obliterate the nuclear arsenal of its enemy by firing a beam of neutrinos straight through the Earth. This of, course, is nonsense the earth would be nearly transparent but a lethal dose of neutrinos does not seem possible.Is it possible to make a neutrino bomb?Ī super-powered neutrino generator could in theory be used to instantly destroy nuclear weapons anywhere on the planet, according to a team of Japanese scientists.
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