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Monday, December 25, 2017

Gravitational Waves

Gravitational Waves from two neutron stars. Image Credit : LIGO
     Gravitational waves are the ripples in the space-time fabric, which are caused by the violent and energetic process of the universe. These waves are produced from the collision of neutron stars, massive acclerating black holes, stellar cores, supernovas, coalescing neutron and white dwarfs. Famous physicist Albert Einstein predicted the existence of gravitational waves in 1916, he proved by his mathematical expression. After 20 years of prediction of gravitational waves, scientists detected the gravitational waves from binary pulsar star in 1974. 


     In 1974, two astronomers working at Arecibo Radio Observatory in Puerto Rico discovered a binary pulsar two extremely dense and heavy stars in orbit around each other. This was similar to the theory of relativity in which the body radiates gravitational waves from the source in a space-time fabric. The study had continued for 40 years about the binary pulsar star. In 14 September 2015, Laser Interferometer Gravitational Wave Observatory (LIGO), first time detected the distortion in the space-time fabric. the distortion was due to the collision of fast rotating black holes nearly 1.3 billion light years away. LIGO made a huge achievement after detecting the waves. When it was detected, the sound was like a "bird chirp".

Need to detect Gravitational Wave:

     Gravitational wave can only be detected by LIGO observatory, because it was designed in such a way that it can detect any small or tiny distortion in the fabric of space time. Similar to the discovery of gravity, the gravitational wave will change the view of space science and will help us to understand the origin of the universe in a effective manner.

Data in gravitaional wave:

     Astronomers and data scientists stated that gravitational waves are not like electromagnetic radiation, it is quite different from the EM wave. It carry information and data of cosmic object in space-time, and it travel at a speed of light in the universe. They interaction between the dark matter and gravitational wave in space is very weak.

Souces of waves:
  • Neutron stars
  • Binary neutron stars
  • Binary black holes

LIGO - Gravitational Observatory, Hanford, USA

     LIGO stands for Laser Interferometer Gravitational Wave Observatory is a observatory established in Hanforn and Livingston in the shape of "L". They are of 4km x 4km of length, It was constructed to act as antenna for the detection of gravitational waves.It can detect waves at a wavelength of 30 Hz to 7 kHz.

Observatories and Collaborations:

     Many scientists and engineers are involved in the detction of  gravitational wave outside the Hanford,Livingston,Caltech and MIT. They are all part of scientific collaboration of LIGO.
  • LIGO's Dual detectors
  • LIGO-India (planned joint work with India)
  • Virgo, GEO and KAGRA   
Research Papers on Gravitational Wave Detection:
  1.  Eberle, Tobias, et al. "Quantum enhancement of the zero-area Sagnac interferometer topology for gravitational wave detection." Physical review letters 104.25 (2010): 251102.
  2.  Harry, Gregory M., and LIGO Scientific Collaboration. "Advanced LIGO: the next generation of gravitational wave detectors." Classical and Quantum Gravity 27.8 (2010): 084006.
  3.  Abbott, B. P., et al. "LIGO: the laser interferometer gravitational-wave observatory." Reports on Progress in Physics 72.7 (2009): 076901.
  4. Abadie, Jea, et al. "Predictions for the rates of compact binary coalescences observable by ground-based gravitational-wave detectors." Classical and Quantum Gravity 27.17 (2010): 173001. 
Image Credit : LIGO
Journal Credit : Google Scholar


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