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
Not only is the sun up in the sky at the same time every day, but it also sets in the same spot, and it does that all over the world. And even though it’s hard to imagine, the sun moves across the sky at the same rate every day.
Let’s say you’re on vacation in a gloomy city like London, and you ask yourself, “Is the sun brighter on some days?” The answer is: “No“. Actually, the sun gets brighter every day of the year. But if you mean brighter in terms of the amount of sunlight it receives, then the answer is “no”.
It’s hard to pin down the exact time of day that the sun shines brightest since there are several factors involved. One important factor is the angle of the sun relative to the horizon, which changes throughout the day, depending on the time of year, and also depends on the time of day. Another factor is the local latitude, which affects the amount of daylight in winter and the amount of daylight at dawn and dusk. The remaining factor is the height of the sun in the sky.