by Bodhi Dhanapala, Quebec  Canada.

Most of us have no idea of Einstein’s theory of relativity. Sri Lankans have heard the claim of Nalin de Silva, an ex-Dean of Science at Kelaniya  that Einstein’s theory is just an unmitigated lie (“Patta-Pal-Boruvak”) —  a “just so story” dependent on the  Judeo-Christian cultural mindset.  Truth be told, science had to battle that very Judeo-Christian hegemony at every step, with celebrated scientists burnt at the stake or put under house arrest.

Scientists in Washington announced the observation of waves of the gravitational field, the analogue of electromagnetic waves (radio waves) that are produced when you move a magnet too and fro. Similarly, when massive objects move at high speed, they produce gravitational waves whose strength depends on how massive, and how rapid is the movement. In this case two giant black holes moving at half the speed of light produced waves strong enough to be detected.  Such waves must exist if Einstein’s theory of  gravity is correct, but their detection had required a half century of effort because the waves are very weak. This discovery now confirms a major aspect of Einstein’s theory. It opens a new field of astronomy that uses gravitational waves instead of light or radio waves. Such waves can tell us about the beginnings of our own universe, and other possible events in our multiverse which has many other big bangs inaccessible to ordinary telescopes.

The essence of the theory of relativity is that the laws of physics hold true universally, irrespective of how you are moving. That is, your microwave, radio or wristwatch will work perfectly, at home, on a ship, in an airplane, on a rocket or on another planet in exactly the same way as at home. This seems a very innocent statement. It was the main content of Einstein’s celebrated  paper of 1905.  This is called the principle of relativity.  It should cause no surprises except  that one law of physics requires that light to have a speed of  nearly 300,000,000 meters per second. So  this  has to be the same for every one, at what ever speed he or she is going. If I were on earth, and  you were on a space ship going at 1/4 of the speed of light, normally  you would see light  going away from you at 3/4 of its speed. But no! Relativity says we both see light running away from us at the very same speed!

This can only happen if  your clock runs slow relative to mine, although the clocks work perfectly. From your point of view, my clock runs fast compared to yours! Your meter stick shortens compared to mine, while my meter stick lengthens compared to yours. So, all these happen so that the speed of light is always 300,000,000 meters/s, for both of us, as measured by our individual meter sticks and clocks!

Distances and time intervals are quantities relative to your personal “frame of reference”, being different in another frame. There really are only “events”. There are no space-locations or “time” that every one can agree on!  The sum total of all events is   “spacetime”, and the only thing everyone can agree on is the space-time separation between events. Space has three dimensions (length, width, and height, labelled x,y,z) and time has just one dimension (t). Hence spacetime has four dimensions (x,y,z,t) entangled together.  Your GPS needs four satellite signals to locate you since it uses Einstein’s equations!

In 1915 Einstein  launched another big idea.   If you put some iron filings near a magnet, you see the “magnetic field” around it. In the same way, every object, be it the earth, or a coconut, or a person, has a “gravitational field around it”, just like the  magnetic field around a magnet. Isaac Newton had the genius to realize that objects attracted each other, but could not explain how. Newton formulated astonishingly accurate equations describing the motion of planets in space, tides on earth, and all motions and mechanics used successfully by engineers today . Einstein added what was missing in Newton’s theory by clarifying the nature of the “gravitational field”.

Einstein  suggested that the mass of an object is simply a curvature in spacetime. The more massive the object, the more curved the spacetime near it, making a “mound” in the spacetime. So, “gravitational attraction”  is  simply objects responding to the local curvature felt by them. Planets move along the “locally flat” path in the curved spacetime, just as water flows in the valley between the mounds of  hills.

This does not mean that  “Einstein has done away with gravity”. Such simplistic statements are found in the popular literature to “shock” the reader. Dr. Nalin de Silva criticizes Sri Lankan  as well as Western academics for “thinking that there is a gravitational attraction, even a century after Einstein showed that gravity is a fiction” (e.g, see Vidusara 18-11-2015, and other such articles). Einstein himself warned against such simplistic errors by saying ( see Relativity, The special and General Theory,  by Albert Einstein, 1959, p 176):

“Now we might easily suppose that the existence of a gravitational field is only an apparent one. … This is by no means true … It is, … impossible to choose a body of reference such that … the gravitational field of the earth (in its entirety) vanishes” .

Dr. Silva went to Sussex  University  to study theoretical physics. He likes to claim (Vidusara, 30-12-2015, and 13-1-2016 ) that he came back after 1.5 years with a degree certificate, thanks to his supervisor who bent rules to send him back!  Gravitation, Quantum Theory, and the mathematics behind them demand a lifetime to “understand” them. The team of scientists who successfully measured gravitational waves had worked on it for many decades. This is more than a great intellectual achievement where a physics theory, the prediction of a black-hole event, and being ready to observe it, all came together.  This heralds new  precision tools  for studying and adapting our environment to fit  our needs. It is a great engineering achievement well beyond  putting a man on the moon, demanding an accuracy and sensitivity similar  to those for  seeing a human hair  some zillions of miles way.  The black holes collided  1.3 billion years ago, and it took that long for the light and gravity waves to come to earth!

There are people who think that only what is directly seen by the eye has to be accepted, and everything else is not. So, such people say, show me gravity, I cannot see it! Science deals mostly with signals which are too small to be felt by us or seen by us. So we have invented tools like telescopes, microscopes, lasers etc., that can convert all sense data” into pointer readings. A pointer reading is a definite thing on which every one can agree on, because either the pointer is pointing to a given number that we can all agree upon, or it is not. Thus scientific knowledge is public knowledge, for all to see irrespective of whether we are in a Western Culture or an Eastern culture. It is not based on some hearsay that some woman with the power to talk to Gods” has told such and such” and you must believe her even if you cannot verify it!  But how can everybody verify this experiment without special training? Of course, you need some education even to verify an obituary by reading a newspaper.  Indeed,  according to Dr. Silva, once you are over 25, you should be able to do physics, if you had at least followed a few years of study of Physics.  This is unlike in the case of revealed knowledge, where the woman who has special powers” has so only by God’s grace – Devapassiko!