Nutrinos and Energy ```Name: Joseph R. Status: other Age: 50s Location: N/A Country: N/A Date: 2000-2001 ``` Question: Gravitational potential energy converts to kinetic energy as a particle approaches a gravitating body and returns to latency if the particle climbs back out of the gravity well. It does not contribute to the increase in mass of the body upon particle capture. But the kinetic energy carried by a neutrino converts to rest mass if the neutrino interacts with a nucleus. If a neutrino picks up kinetic energy from the gravitational potential upon approach to a gravitating body, and then interacts with a nucleus fixed in position on the surface or undergoing centrifugal acceleration in an accretion disk, then energy derived from the gravitational potential converts to rest mass and this does contribute to the increase in mass of the body upon particle capture. Is this not a violation of energy conservation? What is the ultimate source of the rest mass energy derived from the blueshift portion of the neutrino's total energy? Replies: Joseph, It is very important to realize that mass IS a form of energy. Albert Einstein discovered this with his work in special relativity. It is the basis of nuclear energy. When dealing with things on the level of atoms, nuclei, and particles, it is possible to convert mass-energy into other forms of energy. The reverse also happens. The gravitational potential energy can become mass-energy through the relation E=mc^2. For a comet coming in from space, gravitational potential energy (GPE) changes into kinetic energy (KE). If it doesn't crash into anything, KE changes back into GPE as the comet goes back out into space. For the neutrino coming in from space, GPE again changes into KE. Because the neutrino joins with the nucleus, a majority of the KE changes into mass energy. Some may remain as KE of the new nucleus (with the joined neutrino). Still, total energy before the event equals total energy after the event. You have to include mass energy (mc^2) for things to balance. Dr. Mellendorf Illinois Central College Click here to return to the Physics Archives

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