You’ve heard the expression: “As sure as the sun will rise tomorrow.” The sun is for us a pretty steady and dependable thing. Whether we see it or not, we know it is always there, shining in the same old way.
And for all practical purposes, that is good enough. The sun is a star, and so it shines by its own light. V/here does it get this energy? It is now believed that hydrogen atoms in the very hot interior of the sun combine to form helium. When this happens, it sets free energy which flows steadily to its surface. And the sun should be able to continue radiating this energy for many millions of years to come.
But if we examine the sun in a little more detail, we do not get quite the same “steady” picture. First of all, the sun is not a solid body like the earth, at least at its surface. In fact, different parts of the sun rotate at different rates. The sun’s rate of rotation increases from 25 days at its equator to 34 days at its poles.
The outer layer of the sun, called ‘the corona”, is composed of light, gaseous matter. The outer part of this corona is white, and it has streamers that extend out millions of from the edge of the sun. These may cause small, but definite differences in the way the sun shines.
Another layer of the sun, called “the chromosphere”, is about 9,000 miles thick and is made up largely of hydrogen and helium gas. From this, there project huge clouds called “prominences”, which may rise to heights of 1,000,000 miles. These also are part of the “unsteady” way the sun shines.
How Many Hours A Day Does The Sun Shine?
There is an average of 2439 hours of sunlight per year (of a possible 4383) with an average of 6:40 of sunlight per day