What is a total solar eclipse?
A total solar eclipse occurs when the moon moves directly between the sun and the earth. When you look at the sun and the moon in the sky, you quickly notice a strange but wonderful coincidence: both have apparently the same size – the sun and the moon seem to have both a diameter of one-half degree. Ok, sure, they are not really the same size. The diameter of the sun is in fact 400 times the diameter of the moon. But, the sun is also 400 times further away from the earth than the moon, which makes their respective diameters look the same. When you are on the earth, looking up at the sun and the moon, you must be in a very specific and limited zone to see the moon cover completely the face of the sun. The match is so good that the moving “path of totality” (the shadow of the moon on the surface of the earth) is never more than 167 miles of diameter – usually less, depending on the exact distance of the moon at the time.
