by Christopher Reilley

Created on: July 16, 2008   Last Updated: July 20, 2008

"Daddy, what does E=mc(2) mean?"

"Do you want the long answer or the short answer?"

"Both," she said with a grin. She knows how to wind me up, that one does, and sometimes I think she asks me these questions just to hear me talk.

"The short answer is this: Energy and Mass are two aspects of the same universal stuff, and that famous equation is the relationship between the two, how much of one equals how much of the other, and vice versa."

"No way."

"Total way." I wound up. "Albert Einstein first put the most famous scientific formula in the world on paper in 1905 as one small part of his general theories of relativity. Einstein had discovered, and was trying to explain, an intimate relationship between mass and energy. Energy is the ability to make something happen, mass is the physical weight of a material object. You with me so far?"

"So mass is the car, and energy is the gas to make it go." The kid is a genius.

"That's a great way to put it simply, kiddo. Now, it seems logical that energy is energy, and mass is mass, period. But Einstein discovered that energy and mass are two interchangeable aspects of the same thing, which all of the big-brained science guys running around in lab coats; the finest minds at humanities disposal, and they call it mass-energy for simplicity's sake."

For the mathematically unchallenged (I'm pleased to say that she got this part easily) if m stands for an amount of mass, and E stands for the equivalent amount of energy, the equation says you can determine that amount simply by multiplying m by a number represented as c(2). The number c(2) is incomprehensibly large it is the square of the velocity of light so you can get an enormous amount of energy from a tiny speck of mass.

"Energy equals mass time the square of the speed of light?" At first, she looked pleased, then puzzled. Umm, so.what?"

So what? This is the finest thinking that any human being has ever come up with so far, that's so what." I grinned at her, and she grinned right back. "The reason that this is not more in your face and on the news in everyday life (with one huge exception) is that most of the common, daily, energy-producing adventures we experience, such as turning food into energy or burning coal and gasoline are all chemical reactions. In all chemical processes the amount of mass converted to energy is miniscule, I mean tiny, I mean it's harder to measure it than it is worth."

At her look I continued. "OK, even if I blow off a stick of dynamite, definitely a chemical

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