gravitational-lensing

Context:

  • NASA is planning to launch James Webb Space Telescope (JWST) in 2021, which will use a natural phenomenon called “gravitational lensing” to carry out astronomical observations.
  • This programme is called TEMPLATES (Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation)

About Gravitational lensing

  • The phenomenon of gravitational lensing occurs when a huge amount of matter, such as a massive galaxy, cluster of galaxies or a black hole, creates a gravitational field that distorts and magnifies the light from objects behind it.
  • Gravitational lensing is based on Einstein's theory of general relativity (Mass bend light).
  • Normal lenses such as the ones in a magnifying glass work by bending light rays that pass through them in a process known as refraction, in order to focus the light somewhere else.
  • Similarly, the gravitational field of a massive object causes light rays passing close to that object to be bent and refocused somewhere else.
  • In effect, gravitational lenses act like natural cosmic telescopes.
  • The effect allows researchers to study the details of early galaxies too far away to be seen otherwise with even the most powerful space telescopes.
  • Also, it can help astronomers to know about black holes, dark matter, etc.

About James Webb Space Telescope (JWST)

  • The James Webb Space Telescope (sometimes called JWST or Webb) will be a large infrared telescope with a 6.5-meter primary mirror.  
  • The telescope will be launched on an Ariane 5 rocket from French Guiana in 2021.
  • Webb will be the premier observatory of the next decade, serving thousands of astronomers worldwide. 
  • It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
  • Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA).