Written by Talent KAS

Related Topics: Science & Technology, James Webb Telescope


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.

What is Gravitational Lensing?

  • It is an effect of Einstein’s theory of general relativity – simply put, mass bends light.
  • The phenomenon occurs when a huge amount of matter, such as a massive galaxy or cluster of galaxies, creates a gravitational field that distorts and magnifies the light from objects behind it.
  • In effect, these are natural, cosmic telescopes and are called gravitational lenses.


  • The large celestial objects which act as gravitational lenses will magnify the light from distant galaxies that are at or near the peak of star formation.
  • 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.
  • Gravitational lensing is useful to cosmologists because it is directly sensitive to the amount and distribution of dark matter.


The NASA program aimed at using gravitational lensing via its James Webb telescope is called “Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation (TEMPLATES)”.

About James Webb Telescope

[Sources: The Indian Express, NASA]

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