Dinesh's photos with the keyword: Book of nothing

The Binary Pulsar PSR 1913+16, one of about 50 known systems of the type. It contains two neutron stars orbiting around one another. One of the neutron strs is a pulsar and emits pulses of radio waves which can be measured to high precision. These observations show that the orbital period of the pulsar is changing by 2.7 parts in a billion per year. This is the change predicted by the general theory of relativity due to the loss of energy by the radiation of gravitational waves from the neutron stars