If you follow science, you might have had a flooded social feed today with tags like Gravitational Waves detected by LIGO, Einstein’s theory of Relativity predictions have been observed, or probably something along the same lines. Let us discuss what gravitational waves really are and why detecting them is such a big deal.

What Are Gravitational Waves?

In the year 1916, a brilliant young scientist by the name of Albert Einstein formulated a theory that would revolutionize modern physics (and increase the width of our textbooks). He called it the Theory of Relativity. In his thesis, Einstein predicted that bodies having enormous mass warp the space around it. We can understand this by imagining a sheet of cloth and placing a bowling ball on it. The part of the sheet on which ball is placed is curved due to the weight of the bowling ball.

Our Space-time (the fourth dimension, supposedly) is also warped in a similar way due to objects having a high mass. In fact, it is warped by any object having mass, your body, your smartphone, even the tiniest button on your shirt warps the spacetime, but the warping is so minuscule that it does not matter at all. Our sun, however, warps the space-time considerably so much so that we are affected by it, but even that is not much. Now, Since space-time can be warped what would happen if an object having very high mass moves at a very high velocity through it?

Curved spacetime due to earth
Spacetime is warped by an object having large mass

The same thing that happens if an object moves through a tub of water. Ripples are created and they extend outwards towards space-time. Physicists argued for ages what actually these waves are, whether they have any physical significance whatsoever (not that they had anything better to do). The Chapel hill conference resolved this debate and the physicality of the gravitational waves was determined.

How were these gravitational waves detected?

LIGO an acronym for Laser Interferometer Gravitational-Wave Observatory was established in 1992 and uses a Michelson’s interferometer to detect the space-time warping of the ripples. There are two facilities, one in Hanford and one in Livington in The United States of America.

LIGO, hanford branch
Hanford, Washington. LIGO is a very large L shaped Michelson’s interferometer.

Michelson’s interferometer is a device that splits a beam into two parts and lets their waves interfere to produce a standing wave or no intensity light. The advanced interferometer at LIGO is capable of detecting gravitational waves of amplitude as small as an atom’s nucleus, That is really small. When these waves travel through the mirrors in the interferometer they warp it, shift the mirrors slightly (width of an atom) with respect to time. This is detected by a photosensitive sensor.

“It’s the first time the Universe has spoken to us through gravitational waves. Up until now, we’ve been deaf.”

PSR B1913+16 is a binary pulsar system. It has two black holes revolving around each other. Now black holes are really small giants. They have near infinite mass and near infinite density. which essentially means their area is very small(negligible even). they produce massive gravitational waves and warp space-time around them. This system is about 1.3 billion light years away from our little home. now these two black holes merged and produce enormous energy and waves. Although it took a lot of time to reach our planet, we were ready when it did.

Gravitational waves detected by LIGO
The waveforms detected by LIGO by the spacetime warp of gravitational waves

How does it affect the future?

LIGO detecting gravitational waves finally proves the long discussed prediction of Einstein’s theory of relativity. It changes the way we have been using observing the universe around us. It changes the way gravity has been understood for a long time. This discovery could prove an insight into the big bang and we could finally figure out the burning question of the starting of time.

“There is a Nobel Prize in it – there is no doubt”

We could be witnessing an ushering of a new era of astrophysics where we understand the gravitational force a little bit better. Who knows maybe we will make a warp drive in the coming future (Warp Speed Ahead, Mr. Sulu).

  • sidhartha sarangi

    cool website , but just one question, why copy the design from … you know what i am talking abt!