Gravitational lensing is extremely helpful in discovering new things in our universe, how? let’s see that in a bit. Gravity itself is fascinating, when a phenomenon occurs where there is something to do with both Gravity and light, that’s something amazing.
From Einstein’s theory of relativity, we know that mass curves the space around it. This is where the phenomenon called Gravitational lensing comes into picture. Light gets deflected(or bends) when it travels along the curvature of space and time containing a massive object, this phenomenon is called Gravitational lensing.
Astronomers use gravitational micro-lensing to detect planets around other stars. The foreground star acts as a lens for a background star. As the star brightens up, you can detect further distortions which indicate there are planets. It help discover new planets. But the thing is, they are very rare events.
It was first observed by Arthur Eddington and Frank Watson Dyson in 1919 during a solar eclipse. The stars close to the Sun appeared slightly out of position, showing that the light from the stars was bent.
Gravitational lensing acts as a magnifying glass for distant objects making them easier to observe.
And the most funny yet helpful thing with gravitational lensing is, we can even observe invisible things in our universe like “Dark matter”. It doesn’t emit or absorb light on its own, we can’t see or observe or contain it. BUT, it has mass and responds to gravitational lensing.
Here is an example of a gravitational lensing called the Einstein cross. In this image, a single object appears as four objects. A very distant quasar(quasars are distant and extremely bright objects powered by black holes a billion times as massive as our sun) is thought to be positioned behind a massive galaxy.
The gravitational effect of the galaxy has created multiple images through gravitational lensing on the light from the quasar.
So, this is a very special scientific happening which gives us a hope or even a start to play with dark matter;) Of course that’s super tough. Lets see!!