Revisit E=mc2… Einstein’s prime concern was creation not annihilation…
As parties of various political hues jeer or cheer the Indo-Us nuclear deal, spare a thought for the man who made it all possible. No, not George Bush but Albert Einstein. For the real power behind nuclear reactors is Einstein’s equation. Yet this legendary equation is not even primarily about nuclear processes; rather, it’s a crisp statement of far-reaching relevance. Once you understand it, there’s something magnificent about it: I’ll confess that when I see the equation E=mc2, I sometimes feel the same shudder and awe that I feel standing in front of the Taj Mahal.
So, what does it mean? Well, lets look closely.(relax, it wont hurt). On stage left, we have E. E stands for energy, and energy is the ability to move things. When Sachin’s bat strikes the ball, we say it has a lot of energy because it can move something, in this case that poor battered ball. Meanwhile, to the right we m, for mass, which you can roughly think of as weight. Mass is applied by ‘c squared’, which is the speed of light. Ignore the speed of light for a moment. What the equation is telling us, pure and simple, is that energy and mass can be equated, converted to each other-like rupees and dollars.
This is a profound revelation. Here’s why. We are used to thinking of fast-moving objects (a train, a plane) as highly energetic. Similarly, we had previously thought that an object that had come to a standstill had used up all its energy. But the equation says that there’s actually vast untapped reservoir of energy left, stored up in mass itself. It’s as if we’ve discovered that gas tank that we thought was empty in fact holds a secret reserve.
Now, because light travels so absurdly fast-seven rounds around the earth in one second flat- mass is multiplied by a huge number, in our usual units, when converted to energy. In terms of analogy, its as if the conversion is not between dollars and rupees but between dollars and some tinpot currency, like the old Turkish lira. Just as you would get over a million Turkish liras for one dollar, you can get a lot of energy for a tiny bit of mass. And so it is: the devastation unleashed by the Hiroshima atom bomb came from converting less that single gram of mass to energy.
Nor is it all nuclear. Every breath u take..every move u make.., involves E=mc2. As u move that mouse, a miniscule amount of mass is used up to provide the energy for that action. As you blink, some mass is converted. To power your heartbeat it’s again the omnipresent equation in action.
Beautifully, the very equation that destroys also holds the the key to creation. Indeed, what appeared in Einstein’s paper was not E=mc2 but m=E/c2. Although that’s an equivalent equation, the emphasis is rather different. Whereas E=mc2 tells us how much energy is released when mass is destroyed, m=E/c2 tells us how much mass can be created from energy. Creation and annihilation, in one.
Einstein was after creation, not annihilation. He wanted to know where mass came from. And in his glorious equation an important part of the answer lay revealed. Mass comes from energy. After the Big Bang, our universe was filled with intense hot radiation. Magically, that energy turned itself into matter, using m=E/c2, matter that was to later become you and me.
As for nuclear weapons, this is what Einstein, an ardent pacifist and a deep admirer of Mahatma Gandhi, had to say: “I made one great mistake in my life when I signed the letter […] recommending that atom bombs be made.”
P.S: Article by Maulik Parikh for Outlook, January 2007.
Maulikh Parikh is a theoretical physicist at Inter-University Centre for Astronomy and Astrophysics, Pune.