Gravitational waves: Why science expects to create a ripple today

Amid expectations worldwide that the announcement will be about the discovery of gravitational waves Einstein spoke of.

Written by Amitabh Sinha | New Delhi | Updated: February 11, 2016 9:16 am
 gravitational waves, Albert Einstein, General Theory of Relativity, Caltech, MIT, LIGO, LIGO gravitational waves, IUCAA, IUCAA pune, Ligo project IUCAA, india news, science news, latest news Existence of gravitational waves had been predicted by Albert Einstein exactly 100 years ago in his paper on the General Theory of Relativity. (Source: Illustration by Subrata Dhar)

On Thursday, international scientists are scheduled to make an announcement that is already being billed as the unveiling of one of the most important scientific discoveries of all time. Amid expectations worldwide that the announcement will be about the discovery of gravitational waves Einstein spoke of, AMITABH SINHA explains what that would mean to science and the common man.

What are the scientists going to announce?

As of now, all that is known is that at the National Press Club in Washington, at 10:30 am local time (8:30 pm IST) Thursday, scientists of Caltech, MIT and the LIGO (Laser Interferometer Gravitational-wave Observatory) international project will present “a status report on the effort to detect gravitational waves — or ripples in the fabric of space-time — using LIGO”. But the internet is already abuzz with chatter that the LIGO project has succeeded in its primary objective of detecting gravitational waves. Gravitational waves have never been detected before, though indirect evidence of these waves have been found and resulted in a Nobel Prize in 1993. Their existence had been predicted by Albert Einstein exactly 100 years ago in his paper on the General Theory of Relativity. India is an important partner in the LIGO project and the announcement will be simultaneously made at the Inter-University Centre for Astronomy and Astrophysics (IUCAA) in Pune.

What are gravitational waves?

It is a concept that would challenge one of the foundations of Newtonian physics. Isaac Newton had postulated that the force that makes an apple fall to earth is also the one that keeps the moon in its orbit around the earth. Essentially, every celestial body exerts an attractive force on every other. This force, he proposed, was proportional to the masses of the two bodies and inversely proportional to the square of the distance between them. So, the greater the distance between the bodies, the lower the gravitational force between them. This resulted in his famous equation of gravitation, which was written as

F = G × m1 × m2/r^2

where F is the strength of the force of gravitation, m1 and m2 are the masses of the two bodies, r the distance between them and G a universal constant that Newton introduced and whose value was calculated to be 6.674 × 10^(-21) Newton sq m/sq kg.

Newton’s gravitational law described the motion of heavenly bodies with amazing accuracy and withstood the test of time for about three centuries. In fact, this law is enough to guide most of the activities of modern space programmes. But just like Newton’s laws of motion were found to break down in some special cases in the new revolutionary physics that began in the first couple of decades of the 20th century, his law of gravitation too was considered inexplicable by Einstein. The latter went on to propose an alternative theory, which is where gravitational waves came in.

What did Einstein have a problem with?

Though mathematically accurate, Newton’s law doesn’t say why two bodies are attracted to each other. Einstein also had a problem with the fact that the force was exerted on the two bodies instantaneously. He had shown in his landmark papers of 1905 that nothing in the universe, not even information, can travel at speeds greater than that of light — and two bodies can be separated by any distance.

So what alternative did he propose?

While formulating his General Theory of Relativity, Einstein proposed that gravitational attraction was a result of the bending of the fabric of space-time by the equivalent of a heavy object. This is very often elucidated by an animation in which a large ball is placed on a rubber sheet, creating a curvature in the sheet. When a smaller ball is rolled on the rubber sheet, it rotates around the large ball along the curvature for a while before falling into it. Einstein said the sun, the earth and all other bodies formed similar curvatures around them, and this was the reason for smaller objects getting pulled towards them. But since the earth, sun and everything else are also moving, the curvature around them moves too. This creates ripples in space-time, just like a moving boat in water creates ripples. It is these ripples that Einstein called gravitational waves.

So what if gravitational waves have now been detected?

Besides the fact that it would establish Einstein’s genius all over again, the discovery of gravitational waves would establish the correctness of General Theory of Relativity. It would assure the world that science has been developing on the right course through the last one century. The discovery of gravitational waves would mean that now all four fundamental forces of nature — electromagnetic, weak and strong nuclear forces being the other three — would be associated with wave-like properties. It would, therefore, be a significant step forward in the effort to unify the quantum theory, which operates at subatomic levels, and gravitational theory, which operates at cosmic scales, into one single theory of nature.

The detection of gravitational waves would enable astrophysicists and astronomers to “see” the universe which is, as of now, invisible to them. Almost 95 per cent of the universe is known to consist of dark matter and dark energy, which does not emit any light or any other electromagnetic waves, and therefore have not been detected even by the most sophisticated instruments. Black holes, for example, cannot be “seen” but they do produce gravitational waves, and now can be detected using these.

But does it alter the common man’s life?

For scientists, it changes their very understanding of the universe. With gravitational waves established, Newtonian gravity would be overthrown in favour of Einstein’s gravity. The rest of the world, however, can go about their daily lives as usual — as of now. As one scientist put it, no one knew what was in store when electromagnetic waves were first discovered, just as James Clark Maxwell had predicted, in the latter half of the 19th century.

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  1. P
    Period
    Feb 11, 2016 at 4:14 am
    "Amid expectations worldwide that the announcement will be about the discovery of gravitational waves Einstein spoke of, AMITABH SINHA explains what that would mean to science and the common man.". LOOKS LIKE AMITAB SINHA WANTSBTO PROJECT HIMSELF AS A SCIENTIST WHO WANTED RO SHOW OFF WITH HIS CAPITALIZED NAME. He forgot to proof read and he exposes himself.
    Reply
    1. r
      raw.thoughts
      Feb 11, 2016 at 6:56 am
      Writing 5th standard formula, don't you have anything more scientific to write?
      Reply
      1. V
        Vinutha
        Feb 11, 2016 at 4:11 am
        brahmins INVENTED gravitational waves many billionia before Einstein DISCOVERED. It was using these waves they travelled to Shapely Super cluster. Having heared that Harsh Vardan is the Minister of science and technology those fellows are returning back tomorrow to vindicate him.
        Reply
        1. C
          Chavali
          Feb 11, 2016 at 5:24 am
          Scientific knowledge is in perpetual evolution; it find itself changed from one day to next." Jean Piaget. Why blam Dr.Harsh Vardan alone?
          Reply
          1. M
            MiLady
            Feb 11, 2016 at 10:03 am
            This is the most indepth explanation I've read from an Indian media house. Kudos to IE if this was done inhouse rather than the usual agency reports. This is what you get when you invest in good science journalists, and its remarkable since only big media houses like the BBC and may be sometimes (our own) The Hindu are the capable of doing that. IE should also have added some animations and other stuff to explain that. Alas they don't have any leverage in the electronic media
            Reply
            1. T
              takloo
              Feb 11, 2016 at 11:05 pm
              Einstein was the biggest fraud on the earth ... created by j3w media ... plagiarist ... see him exposed or just punch in plagiarist Einstein and you will get thousands of websites giving you all the points
              Reply
              1. R
                rake
                Feb 11, 2016 at 7:17 am
                If you have time after findings faults on other's work, try doing something for yourself...it feels good you know to create something (even if its faulty).
                Reply
                1. R
                  rake
                  Feb 11, 2016 at 7:24 am
                  Whats with the aggression? a Journalist shared a news story with a bit of explanation. If I really want to read science with detailed formulas, I wouldn't read Indian Expresss... Hope you get it?
                  Reply
                  1. M
                    Malcolm
                    Feb 11, 2016 at 2:22 pm
                    Thank you Indian Express for enlightenment... Keep it going the good work!
                    Reply
                    1. M
                      Manish
                      Feb 13, 2016 at 9:32 am
                      The best thing I read today.....keep going indian express!
                      Reply
                      1. D
                        David
                        Feb 11, 2016 at 3:31 am
                        IE! Slavish at best. Are there any great scientists other then Einstein. And what about the guy who came with the concept of shunya (0) and numerals and decimal system. Without which science was not possible.
                        Reply
                        1. R
                          Raju Prajapati
                          Feb 11, 2016 at 8:14 am
                          Confirming existence of waves will tell us we are misguided by so called Einstein fans and it will be biggest setback for human kind. Being unable to detect them they will feel they were made foolish by Einstein. In my view, GR is only a geometrical representation of how gravity works but not why it works. There is no any physics in it. If you see GR, proofs are based on light properties only. It reviles light properties and not property of gravity. Since 1915 we have not found graviton and its related information in real physics and there is no useful technology we developed for humankind. His theory cannot be right until dark matter/Energy/g waves/black s etc. found in real world along with its function/application in universe. We all need to be in real world where 3D space and there is no physical properties in time/m/length (which is used by Einstein in GR) which influence physical things, they are only units. To find the greatest mystery of science think beyond that in real physics. If existence announced then LIGO scientists will be responsible for misguiding our next generations and not Einstein.
                          Reply
                          1. R
                            Raman Vr
                            Feb 11, 2016 at 3:57 am
                            Thank you Mr Sinha for your elucidation.
                            Reply
                            1. X
                              xyz
                              Feb 11, 2016 at 9:49 am
                              Good clean article.
                              Reply
                              1. S
                                Selva Kumar A
                                Feb 11, 2016 at 4:17 am
                                Thank You...Mr.Amitabh Sinha....
                                Reply
                                1. R
                                  Ramaswamy
                                  Feb 11, 2016 at 5:01 am
                                  well written article
                                  Reply
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