The diameter of the sun is about four hundred times the diameter of the moon and the distance of the sun is also about four hundred times the distance of the moon from the earth. As a result, the moon looks almost equal to the sun from the earth. Angular diameter half a degree. But the distance between the sun and the moon from the earth is not always the same because the orbit of the sun and the orbit of the earth are elliptical. As a result, their size is relatively small and large compared to the Earth. The earth is orbiting the sun in an elliptical way. The moon orbits the earth in the same way. The sun is a vast source of light in space. Earth and moon are opaque matter without light. As a result, shadows are formed on the opposite side of the side where the sun is. As the orbits rotate in a straight line, the shadows of the earth and the moon fall on one another. A lunar eclipse occurs when the shadow of the earth falls on the moon. And when the shadow of the moon falls on the earth, a solar eclipse is created in the place under that shadow.