Introduction to general relativity in a setting with comparatively strong gravitational fields. This has become possible thanks to precision observations of binary pulsars. In such a star system, two highly compact neutron stars orbit each other. At least one of them is a pulsar – an astronomical object that emits a tight beam of radiowaves. These beams strike the Earth at very regular intervals, similarly to the way that the rotating beam of a lighthouse means that an observer sees the lighthouse blink, and can be observed as a highly regular series of pulses. General relativity predicts specific deviations from the regularity of these
Radio-quiet neutron star Star), "INS" (Isolated Neutron Stars). Defined as thermally emitting neutron stars of high magnetic fields, although lower than that of magnetars. Identified in thermal x-rays, and thought to be radio-quiet. Compact Central Objects in Supernova remnants (CCOs in SNRs) are identified as being radio-quiet compact x-ray sources surrounded by supernova remnants. They have thermal emission spectra, and lower magnetic fields than XDINSs and magnetars. Radio-quiet neutron star A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly x-rays