What is Gravitational Lensing?

1 min read
What is Gravitational Lensing? Blog Image


Astronomers have recently captured four images of the same background supernova being gravitationally lensed by the immense gravitational well of the foreground supernova.

About Gravitational Lensing:

  • It occurs when a massive celestial body, such as a galaxy cluster, causes a sufficient curvature of spacetime for the path of light around it to be visibly bent, as if by a lens.
  • The body causing the light to curve is accordingly called a gravitational lens.
  • An important consequence of this lensing distortion is magnification, allowing us to observe objects that would otherwise be too far away and too faint to be seen.
  • Theory:
    • Gravitational Lensing was first predicted in 1915 by Albert Einstein, which involves the bending of light by objects of great mass.
    • According to Einstein’s general theory of relativity, time and space are fused together in a quantity known as spacetime.
    • Within this theory, massive objects cause spacetime to curve, and gravity is simply the curvature of spacetime.
    • As light travels through spacetime, the theory predicts that the path taken by the light will also be curved by an object’s mass.
    • Gravitational lensing is a dramatic and observable example of Einstein’s theory in action.
    • Extremely massive celestial bodies such as galaxy clusters cause spacetime to be significantly curved. In other words, they act as gravitational lenses.
    • When light from a more distant light source passes by a gravitational lens, the path of the light is curved, and a distorted image of the distant object — maybe a ring or halo of light around the gravitational lens — can be observed.


Q1) What is Supernova?

A supernova is what happens when a star has reached the end of its life and explodes in a brilliant burst of light. Supernovas can briefly outshine entire galaxies and radiate more energy than our sun will in its entire lifetime.

Source: Astronomers have captured a background supernova being gravitationally lensed by a foreground galaxy.