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272 pages, Hardcover
First published August 8, 2017
"It’s everywhere. At this moment, as you sit quietly reading this book, you are awash in it. At work, it’s emanating from your electronic devices; step outside for lunch, and the sun bathes you in it. You may receive an extra dose of it when you visit your doctor, pass through security at the airport, or drive through city streets, but minuscule amounts of it are with you always.
You cannot see, hear, smell, or feel it, but there is never a single second when it is not flying through your body. Too much of it will kill you, but without it you wouldn’t live a year.."
"The sun illustrates energy conversion beautifully. Technically it’s converting nuclear energy to electromagnetic energy. Put another way, it’s obeying Einstein by changing its mass to energy, as expressed in the famous equation E = mc². Before anyone figured this out (it was Arthur Eddington, in 1920), the sun’s prodigious light and heat were an utter mystery. Science
had already calculated that a massive ball of coal with the sun’s weight— the mass of 333,000 Earths—would completely burn itself out in two thousand years. But the sun is obviously older than this, so it just couldn’t be burning in the usual sense.
It wasn’t. Instead the sun’s high internal heat means that its hydrogen atoms move furiously enough to smash together. When four of them combine, they create a single atom of helium.
That’s the whole story.
It so happens that a helium atom weighs just a smidgen less than four hydrogen atoms, so there is a loss of mass in this fusion process. The mass is released as its energy equivalent. Using Einstein’s equation, the conversion of a single pencil eraser’s worth of mass to energy could light up all the electric bulbs in the United States for thirteen days. In the sun, the conversion involves four million tons of hydrogen per second. That has a bit more bulk than a pencil eraser, so the resulting energy output is staggering.
This is not some theoretical figure. If we had a giant scale and could weigh the sun, our nearest star, we’d find that it actually weighs four million tons less every second. We might get worried and say, “Whoa! Slow down!” But given that the sun has a total mass of two nonillion—that’s the
number 2 followed by twenty-seven zeros—tons, its ongoing loss of mass is not noticeable. It’ll be billions of years before any serious consequences ensue..."