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In astronomy a neutron star is a small, extremely dense star turning at an extremely high rate of rotation radiating X-rays. It is supposedly formed as part of a supernova. Astronomers have purported to have found numerous neutron stars. They have found something, but what they have found is not likely to be a star composed entirely of neutrons.
The concept of neutron stars was first proposed by the Swiss scientist Fritz Zwicky shortly after neutrons were discovered in the 1930's. He based this on the absence of neutrons in cosmic rays. He took the particles of cosmic rays as being the result of supernova explosions. He believed that neutrons were left behind when charged particles were blown away from the supernova explosion by intense electromagnetic radiation. However, neutrons outside of nuclei are unstable and decay into protons and electrons. The half-life of neutrons outside of nuclei is about 15 minutes. Even if there were neutrons in the original cosmic rays there would be none left after those cosmic rays reached Earth many years later.
The concept of a neutron star is now based upon the notion that a nuclear strong force prevails between neutrons which is an attraction. There is a strong force but between nucleons of the same type, neutrons against neutrons and protons against protons, it is a repulsion. Between unlike nucleons, neutrons and protons, it is an attraction. It is this latter force and spin pairing that hold nuclei together. The conventional belief is that all nucleons attract each other regardless of type and that overcomes the electrostatic repulsion between protons. This notion is plausible but there is no evidence for like nucleons attracting each other through the nuclear strong force. The spin pairing of neutrons is an attraction but outside of a nucleus not even one neutron spin pair is formed. The spin pairing and the attraction of unlike nucleons for each other is enough to explain the stability of nuclei.
It is well known that a nuclide with an excess of protons compared to neutrons is unstable. What seems to have been overlooked is that too much of an excess of neutrons compared to protons also produces instability. The maximum excess of neutrons over protons is 60. This occurs for only two nuclides, Cm252 (Curium) and Cf256 (Californium). Both of these are synthetic elements. It is generally believed that most of the complex nuclei of the universe were created by supernova. But somehow the supernova did not create nuclei with more than 63 percent neutrons yet supposedly they created super particles, the neutron stars, of 100 percent neutrons having a mass twice or so that of the Sun and rotating at over 700 times per second.
The reason no nuclides having more than 63 percent neutrons is that neutrons repel each other. There is rigorous empirical evidence for this repulsion. See Neutron Repulsion and Proton Strong Force Repulsion. An agglomeration of only neutrons at nuclear level distances would be extremely unstable; i.e., explosive. The gravitational attraction of the masses of the neutrons would be only a minute fraction of the strong force; something on the order of 10−40.
Somethings are accounting for the phenomena attributed to neutron stars but it is not aggregations solely of neutrons.
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