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What are Gravitational Waves?
Artist’s conception of two black holes orbiting one another and producing gravitational waves. Image Credit :[ NASA ]
Gravitational Waves Are are 'ripples' in the fabric of space-time caused by some of the most violent and energetic processes in the Universe.
- Albert Einstein :predicted the existence of gravitational waves in 1916 in his general theory of relativity.
- Einstein's mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that 'waves' of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond).
How it was detected.
- Einstein's theory of general relativity predicts the existence of gravitational waves (GWs) – ripples in the fabric of space and time.
- Such waves exist – they were confirmed by observing the binary pulsar PSR B1913+16 (Hulse & Taylor 1975), but most astronomers consider this an "indirect detection" of GWs.
- Using bar detectors, space-craft tracking, ground-based interferometers and now, as discussed here, pulsars, scientists have been attempting to make a "direct detection" of GWs.
- GWs are described by an amplitude, frequency (or wavelength) and polarization state. In contrast to electromagnetic waves, the polarizations of a GW are at 45 degrees (see animations to the right). GWs, according to general relativity, travel at the speed of light.