Here Comes the Sun

If you are serious about landscape photography, you must be prepared to get up early, often well before dawn. In the summertime, this can be very early indeed. You have to get out and set up your equipment in time for the “golden hour” that begins at sunrise. The golden hour – actually only about a half hour in the latitudes where I take pictures – is so named because of the light that lends a warm glow to everything when the sun is low in the sky. For those who have trouble getting up before the cock crows, the same phenomenon also occurs at sunset. The sun’s low angle means that light travels farther in the atmosphere and is more diffuse. Colors are more vibrant, and objects stand out. The light is so soft you can shoot directly into the sun. But you must be quick about it. Almost before you know it, the world is ablaze with light or sunk into gloom, depending on which end of the day it is.

Sunrises (or sunsets) are nature’s sleight of hand. As any school child can tell you, what appears to be the sun moving slowly across the sky is actually the earth turning rapidly on its axis, in excess of 1,000 miles per hour at the equator. Why does the earth spin? I remembered enough about Newton’s laws of motion from school to suppose that inertia had something to do with it. But I needed to do some digging to understand how the earth started spinning in the first place. I learned our solar system began as a swirling disk of dust and gas that collapsed upon itself, forming the sun and planets. As the planets coalesced, they began turning faster and faster, much like a figure skater drawing her arms closer to her body to accelerate her spin.

What would happen if the earth stopped spinning? As I discovered, plenty of people worry about such things. It turns out the earth is gradually slowing down, primarily due to the moon’s tidal forces. However, the deceleration is so gradual the earth will be swallowed up by a dying sun long before it would come to a halt. A sudden stop -- say from a collision with a giant asteroid -- is highly unlikely, but the effects would be dire: earthquakes, tidal waves and the probable disappearance of the earth’s magnetic field, for starters. Centrifugal forces from the earth’s rotation cause a bulge at the equator that would disappear if the spinning stopped, sending water cascading toward the poles and flooding land masses in both hemispheres. Once stopped, the planet would spend half the year in darkness and half in daylight, much as the poles do now, and temperature variation would be extreme. None of this, needless to say, would be would be good for continued life on earth.

Those who worry about such calamities tend to focus on the geological effects. However, our lives are much more bound up with the earth’s rotation than mere geology, however cataclysmic the immediate effects of a sudden slowdown might be. All plant and animal life is governed by circadian rhythms that are synchronized with the daily circuit of the planet on its axis. These internal mechanisms tell plants what season it is, when to flower and when to germinate. They control body temperature in animals, along with cardiovascular function, metabolism, feeding behavior and sleep patterns. Long before humans invented mechanical devices to keep track of the time, our lives were minutely regulated by circadian “clocks” operating at the cellular level.

If you happen to be tramping in woods or wetlands before dawn with your camera and tripod, the effects of circadian rhythms will be readily apparent, especially in the springtime. Male songbirds of every stripe will be staking out territories and trying to attract a mate with their singing. Like landscape photographers, they are active at this hour because conditions are favorable for their particular enterprise. Just as the light is better at dawn, the air is usually calmer and sound carries farther in the early morning hours. Songs advertising for a mate are typically longer and more complex than the ones used to stake out a territory. The more accomplished songbirds may even incorporate the distinctive songs of other species into their repertoire to make themselves more attractive to females in their own. In their breeding behavior, as in so many other things, these creatures take their cue from the turning of the earth. So is it love that makes the world go round, or is it just the opposite?

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