In astronomy, with glitch (in Italian "disturbance" or "click") is meant a small and sudden decrease in the revolutionary period of a pulsar.
An initial hypothesis attributed these abrupt variations to the fact that while pulsar rotation slows down, the shape of the surface needs to be adapted to a new hydrostatic balance configuration: the more the pulsar rotates slowly, the more its hydrostatic equilibrium configuration is close to a spherical configuration. The surface of a neutron star or a pulsar, being extremely rigid, can not gradually modify its configuration to fit the new balance and does so only through a series of small but abrupt adaptations. Any shaky causes a change in the distribution of superficial masses and consequently a decrease in its moment of inertia. To maintain the angular momentum, this causes a violent increase in the angular velocity of the pulsar.
This hypothesis is currently abandoned in favor of a description that also considers the internal structure of the neutron star, and in particular the fact that much of its nucleus is a superfluid that occasionally can interact with the rigid external crust. Bibliografiamodifica wikitesto Voices correlateemodify wikitesto
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