Author : Bradley Hughes

E=mc2. The most famous formula ever. Not that there’s been a lot of competition. Einstein’s formula reveals that matter is just one of many forms of energy. Energy is what gets you out of bed in the morning, and energy is what leaves a bruise if you fall on your face in the late afternoon.

Matter is just a form of energy: a new battery will have just the teensiest tiniest more mass now, than when it has run down. If you pull back on a bow, you are adding energy to it, and so the bow has infinitesimally more mass when it’s taunt, than when it’s relaxed. Even for something really energetic, like a thermonuclear explosion the amount of mass involved isn’t very big. If you collected all the detritus from a 25 megaton bomb after the explosion, you would only be missing one kilogram of mass, and an average sized city. One kilogram is probably close to the mass of that first stone used to help kill that first antelope, so very long ago.

But if you go the other way around, and instead of considering the amount of mass in energy, but the amount of energy you can get from a certain mass, then you’re talking.

Think about all the energy your body uses in a day: getting up, walking, climbing stairs, pumping blood, breathing, thinking, remembering. All of that energy is stored as chemical potential energy for a while before you use it. Most of it dissipates as heat, some of it becomes motion, some becomes thought. If you could get all of that energy from converting mass into energy, how much mass would you need? If, instead of eating and breathing, you could directly convert mass to energy for your whole life, how much extra mass would you need to carry around with you?

If you lived to be eighty, you would only need a couple thousandths of a gram. That’s the mass contained in one thousandth of one thin dime. Remember every challenge you’ve surpassed, or run away from; remember every thought, every passion, every need – all of it combined took less energy then is contained in the material missing from a scuff on a dime.

If you were a perfect machine, and you wanted to live among us, you would need to pass as human. You would need to appear to breathe, your blood would pump, your glands would sweat, so you would use about the same amount of energy as we do. But you wouldn’t need to power yourself from air and food. With the right technology, you could convert mass directly to energy. You could live for eighty thousand years on a dime.

You could live among us, observe us and compile your observations for almost as long as there have been humans. Almost ten times as long as we have lived in settled communities and nearly twenty times as long as we have lived in cities. For a quarter, you could live for almost two hundred thousand years. That’s as long as we’ve existed as a species. If you waited to join us until we started building cities, today you’d still have one hundred ninety five thousand years left. That’s plenty of time to live as we do, to love as we do, and to study. Then, when our species’ time has come to an end, there will still be plenty of time to reach your conclusions, and to take them home.