October 8, 2014--E=MC2

The speed of light is very fast, in fact there is nothing faster in the universe. It is a very big number--light travels at 186,000 miles per second, or 299,792,458 miles an hour, which means that the light emanating from the sun, which is about 93 million miles from Earth, takes only 8 minutes and 20 seconds to reach us.

But on a cosmic scale, this is small potatoes.

The galaxy in which our solar system is located is so huge that that hugeness is expressed not in miles but in light years--how many miles light travels in a year. At 186,000 per second, that's very, very far. To give you a sense of that, our galaxy, the disk of the Milky Way, is about 100,000 light years in diameter.

Then, the ultimate measurement, our universe, everything that there is, is 93 billion light years in size, an almost infinitely large number to comprehend.

I have been thinking about the speed of light because a friend, Leslie Woodhead, is writing a book about the Atomic Era, not so much about the science as about the cultural and political consequence of a world full of atomic weapons. He wants to interview me because I am obsessed with The Bomb and how it has affected life on our planet. To satisfy my obsession, I have read and thought much about these issues. In addition, since he's British he wants to gather reflections from Americans who lived as youngsters through the early days of the Atomic Era and Cold War. I qualify in that regard as well.

In thinking what to say to him, I have dipped a bit into the science of the A-Bomb, especially the theory Einstein developed that defined and quantified the convertibility of mass to energy. As evidence and to demonstrate what that would mean in practical terms, converting a relatively smallish mass of Uranium-235 or Plutonium into a massive amount of energy (an atomic explosion), he propounded perhaps the most famous of all mathematical equations--E=MC2, with E representing Energy, M Mass, and C-squared the speed of light times itself.

With the speed of light by far the latest number in the equation, and then squaring it (multiplying it by itself), and then multiplying it additionally by the mass in question, reveals how such a powerful explosion could result in converting such a relatively small mass of radioactive material into energy--the cataclysmic force of an atomic explosion.

For example, a bomb weighing less than 10 tons with a Uranium-235 core weighing only141 pounds of which just one kilogram (2.2 pounds) underwent nuclear fission, an atomic bomb called Little Boy, was dropped on Hiroshima in 1945, exploded with the force of 63,000 tons of TNT. Tons. And killed 135,000 Japanese.

I will want to talk with Leslie about take-cover drills in school where we were taught to dive under our desks if we saw a "blinding flash of light" from an A-Bomb exploding over Times Square, ground zero; and how, after the end of World War II, under Cold War pressure all presidents from Truman to Eisenhower to Kennedy to Johnson to Nixon were under pressure from their military advisers to use nuclear weapons preemptively, in turn, against the Soviets, the North Koreans, Cubans, and Vietnamese; and how this led to the establishment of a "national security state" with inordinate power accruing to the President with Congress assigned a subsidiary role, effectively resulting in  the end of  the Founders' concept of the "separation of powers."

But it will be hard to not be thinking about E=MC2, the speed of light, that kilogram of U-235, and those 135,000 killed that August.