An Eloquent Description of Science and Wonder

As I gathered information for this book, I was continually reminded of the reality that science, rooted as it is in the certainties of the physical world, is a process that necessarily unfolds over time. In school, science classes tend to work according to this linear model; there's a “beginning, middle, and end” to science investigations, no matter how hard teachers may fight the “cookbook” reductionism that threatens true scientific inquiry. Yet, in probing further, I came to understand tha...

 Energy from the Sun to Earth

It is a feature of the way the world is made that two protons together have less mass than two protons separately. This is a startling but indisputable fact. Weigh two protons separately, then weigh them together: the numbers don't match. The numbers differ by about 1 percent. This curious difference is not to be explained by some law of nature; it is a law of nature, as basic to the way the world works as any fact in our possession. The mass discrepancy is equivalent to an amount of energy g...

 Why Nothing Can Go Faster Than the Speed of Light

Einstein's equation gives us the most concrete explanation for the central fact that nothing can travel faster than light speed. You may have wondered, for instance, why we can't take some object, a muon say, that an accelerator has boosted up to 667 million miles per hour—99.5 percent of light speed—and "push it a bit harder," getting it to 99.9 percent of light speed, and then "really push it harder" impelling it to cross the light-speed barrier. Einstein's formula explains why such efforts...

 Why Traveling at the Speed of Light Slows Down Time

the precise time difference between stationary and moving clocks depends on how much farther the sliding clock's photon must travel to complete each round-trip journey This in turn depends on how quickly the sliding clock is moving—from the viewpoint of a stationary observer, the faster the clock is sliding, the farther the photon must travel to the right. We conclude that in comparison to a stationary clock, the rate of ticking of the sliding clock becomes slower and slower as it moves faste...