It’s all relative, child!

‘What is Relativity, thatha?” Ganesh, my 8-year-old grandson, asked. In all decency, if not modesty, I should have said, “I don’t know.” After all, Einstein said, “If you can’t explain to a 6-year-old, you haven’t understood yourself.” I am certainly not one of those who have understood the theory of relativity. But, in utter humility, I braced myself and attempted to explain.

In the 1960s, in the pre-flyover era, the railway line from City Station to Cantonment and then to Bangalore East had a road running next to it almost uninterrupted. My newly married brother and his wife were going to Jamshedpur via Madras and were standing by the train carriage door, waving to us as we drove along in an old Austin. “While my sister-in-law in the train and her brother driving the car were in parting tears, my siblings and I were thrilled by the closeness of the train and the car, when we could actually catch an orange thrown from the train. The speed of the train with respect to our car was almost zero as per relativity,” I said.

Of course, Ganesh was not impressed and said, “Yes, we also move with equal speed while passing on the baton in a relay race; that’s simple, but I thought relativity was a lot more difficult.”

Now I had a challenge. I said, “When you go to outer space, for every moving star, for someone there, the feeling is he is stationary and all others are moving, unlike in a train, where there is no station or trees to confirm the other way.” That caught his interest: “What happens if I move along with light at a higher speed?” Now, I knew he was taught Einstein in school, because that was exactly what Einstein asked when he was a small boy. “You know the answer,” said I, “nothing can reach let alone exceed speed of light.”

Now that we were on the same page, I told him to read Einstein and really understand how distance shrinks, time dilates, and space warps. How and where do we start? Stephen Hawking’s A brief history of time is a good beginning and doesn’t presuppose any math. You may follow it up with Carl Sagan and several other popular works, including Einstein’s own Relativity: The Special and the General Theory, which is very lucid and easy for the common man. Then, with a little math and physics, you may go to Richard Feynman and the like.

“If you really like these and go forward, you’ll be rewarded by a lifetime of adventure and maybe a Nobel, Ganesh,” I said.