GS-3, Science & Tech, Uncategorized

Eureka moment: Gravitational waves found

What is so special about this eureka moment?

  • For the first time, scientists have observed ripples in the fabric of space-time calledgravitational waves, arriving at the earth from a cataclysmic event in the distant universe
  • This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos
  • Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole
  • This collision of two black holes had been predicted but never observed

Let’s first know about Albert Einstein’s general theory of relativity?

  • In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity
  • It introduced a new framework for all of physics and proposed new concepts of space and time
  • Einstein then spent 10 years trying to include acceleration in the theory and published his theory of general relativity in 1915
  • In it, he determined that massive objects cause a distortion in space-time, which is felt asgravity

[ 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 ]

What are Gravitational waves?

  • Gravitational waves are distortions or ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe
  • These ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself

What are the Sources of Gravitational Waves?

  • Any object with mass that accelerates (which in science means changes position at a variable rate, and includes spinning and orbiting objects) produces gravitational waves, including humans and cars and airplanes etc.
  • But the gravitational waves made by us here on Earth are much too small to detect
  • The strongest gravitational waves are produced by catastrophic events such as collidingblack holes, the collapse of stellar cores (supernovae), coalescing neutron stars orwhite dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself


Not one but four types of Gravitational Waves!

  • In order to understand the types of gravitational waves, Laser Interferometer Gravitational Wave Observatory (LIGO) scientists have defined 4 categories of gravitational waves
  • These categories are: Continuous Gravitational Waves, Compact Binary Inspiral Gravitational Waves, Stochastic Gravitational Waves, and Burst Gravitational Waves

But, Why Detect Them?

  • This will open up a new window of study on the Universe, giving us a deeper understanding of these cataclysmic events, and usher in brand new cutting-edge studies in physics, astronomy, and astrophysics
  • More importantly, since gravitational waves don’t interact with matter (unlike electromagnetic radiation), they travel through the Universe completely unimpededgiving us a crystal clear view of the gravitational wave
  • This will provide astronomers and other scientists, first glimpses of previously unseen and unseeable wonders, and greatly adding to our understanding of the nature of space and time itself

So, How does LIGO come into the Picture?

  • LIGO( Laser Interferometer Gravitational Wave Observatory) is the world’s largestgravitational wave observatory and a cutting edge physics experiment
  • LIGO exploits the physical properties of light and of space itself to detect and understand the origins of gravitational waves
  • LIGO has 2 widely separated identical detector sites working in unison as a single “observatory”: one in Hanford, southeastern Washington State and the other in ruralLivingston, Louisiana
  • LIGO has a very close collaboration with the VIRGO collaboration that analyzes data from VIRGO, a 3 km gravitational wave interferometer located near Pisa, Italy
  • Data from LIGO and Virgo are combined and analyzed together by the LIGO and Virgo collaborations
  • Thus significantly increasing the capability of combined data for detecting and using gravitational waves to learn about nature

Is there any Way ahead for India?


  • Yes, because Union cabinet has approved a proposal to establish a state-of-the-artgravitational wave observatory in India in collaboration with LIGO in the US
  • The project will bring unprecedented opportunities for scientists and engineers to dig deeper into the realm of gravitational wave and take global leadership in this new astronomical frontier
  • This will also bring considerable opportunities in cutting-edge technology for the Indian industry which will be engaged in the construction of the 8-km long beam tube at ultra-high vacuum on a leveled terrain
  • With its establishment, India will join the global network of gravitational wave detectors
  • The establishment of an observatory in India assumes importance because the further the distance between the observatories, the greater will be the accuracy in locating gravity waves
  • Maharashtra and Madhya Pradesh are among the states shortlisted for the experiment

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