John Patrick, age 10, of Richmond, Va., for his question:
WHERE DOES THE SUN REALLY SET?
Most of us take it for granted that the sun rises in the east and sets in the west. But a patient young star gazer knows that most of the time this is not quite true. This actually happens only a couple of times during the entire year. The rest of the time it sets somewhat north or south of due west.The sun, as we know, rises above the eastern horizon, climbs over the sky and sets in the west. So do the moon and most of the stars. From this evidence, we might suppose that all these heavenly bodies circle around our planet, earth. Naturally we know that this is not so. ,
Our spinning globe turns us to face the sun and around to face the starry night sky. The earth turns toward the east, which is why the morning sun comes into view in the eastern part of the sky. When the sun sets below our western horizon, it is rising for the folks on the far side of the globe.
The sun itself, of course, is a blazing star that shines day and night. But somewhere on our planet it is always rising and setting because our world is always whirling around.
Our earth is also tilted as it orbits on its way around the sun. During the year, this axis tilt causes first the South Pole and then the North Pole to bow toward the sun. This causes opposite seasons in the Northern and Southern Hemispheres. It also shifts the points where the sun rises and sets.
At the equator, the sun sets in almost the due western part of the sky. In our latitudes, this position varies more with the seasons. In winter, it sinks somewhat south of due west; in summer it sets in the northwest. For us it reaches its northern extreme about June 22, when the days are longest. Its southern extreme occurs around Dec. 21, when the days are shortest.
Twice a year the days and nights are equal all over this spinning, tilted globe of ours. These are the equinoxes that occur on March 21, and Sept. 23. On those days the sun sets in the true west. But you can be sure that when it sets in our sky it begins to rise on the far side of the globe.