Question

Look carefully at this telescopic photo of the Moon. All the following statements are true. Which one is proved by the fact that the line dividing the dark and bright regions is not perfectly straight?

1) Some parts of the Moon's surface are darker in color than others.
2) The Moon goes around the Earth.
3) This is a first-quarter moon.
4) The Moon's surface is not perfectly smooth but rather has mountains and valleys.

Answer 1

The line dividing the dark and bright regions of the Moon is not perfectly straight because the Moon's surface has mountains and valleys.

Step-by-step explanation:

The fact that the line dividing the dark and bright regions of the Moon is not perfectly straight proves statement 4) The Moon's surface is not perfectly smooth but rather has mountains and valleys.

When sunlight streams in from the side during first or third quarter, it causes the topographic features of the Moon's surface to cast sharp shadows. The unevenness of the surface, with mountains and valleys, creates the non-straight line between the dark and bright regions.

For example, if you observe the Moon during first quarter, you would notice that the left side of the Moon is illuminated, while the right side is in shadow. The line dividing the illuminated and shadowed parts would be curved as it follows the contour of the Moon's uneven surface.