Night and Day Cycle

    As you know, the sun rises in the east and sets in the west, then night falls, and the stars come out. Finally the sky lightens, and the whole process begins again. This is our day and night cycle, caused by the earth rotating eastward, which causes the appearance of the sun moving around us. This period is split into twenty-four hours, which is split further into minutes and seconds.  If you where standing at the north pole on a “true” winter night, (no daylight at all due to the position of the axis), the stars would appear to circle above, proving that the earth rotates in space. Below is a time exposure image taken at the Siding Spring Observatory, and a diagram of day and night. A time exposure photograph is taken by a camera that's shutter can stay open for a period of time. 

 

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