How does the moon block most of the sun during a solar eclipse?

Answer 1

It happens because of the distance at which the Moon is located from the Sun. The closer an object is located to it's source the bigger shadow it will cast behind itself, thus with that perfect alignment of Sun then Moon then Earth makes moon cast enough shadow over Earth to see it as being almost perfectly over the Sun, if looking from our perspective. More simpler, in order to understand, think of a flashlight shining on a wall. If you put your hand in-between the flashlight and the wall you will be able to see, as you move it back and forth that the shadow projected on the wall will get bigger as you approach the flashlight, and smaller a you move towards the wall. If you would to draw the circle over the wall even if it is as big in diameter as your whole wall, you will still be able to cover it with a shadow from your hand at a certain point away from the flashlight (assuming that the light from your flashlight is bigger than the area of that circle! :)) Hope it helps