The Energy Game in a Dead Moth

The moth moves across the porch, millimeter by millimeter, a brief stage of a longer journey of energy from the core of the sun to the table of the ants. Protons fuse at the center of the sun, releasing energy. The energy diffuses upward, taking several million years to reach the sun's surface, where it is released as heat and light. The light streaks across ninety-three million miles of space, reaching the Earth eight minutes later, where it falls upon the green leaves of plants. The plants ...

 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...

 Gravity Travels at the Speed of Light

Here's the rub. In Newton's theory of gravity, one body exerts a gravitational pull on another with a strength determined solely by the mass of the objects involved and the magnitude of their separation. The strength has nothing to do with how long the objects have been in each other's presence. This means that if their mass or their separation should change, the objects will, according to Newton, immediately feel a change in their mutual gravitational attraction. For instance, Newton's theor...

 Kangaroo Care and Infant Massage

In the old days, extensive parental contact was discouraged because of fears about injury or infection. Now, however, some hospitals are encouraging parents to spend up to several hours a day holding their preterm infants, preferably upright and skin-to-skin against their bare chest. This approach has been dubbed "kangaroo care" because of its resemblance to early-life marsupials, which are born prematurely but kept warm and nourished in the maternal pouch. Studies have shown several advant...