Final answer:
The Moon reflects light from the Sun, as evidenced by the changing phases of the Moon that correspond to its relative position with the Sun, and confirmed by experiments such as observing the reflected light on a tennis ball in a dark room. Additionally, corner reflectors placed on the Moon by astronauts have provided direct evidence of its reflective nature.
Step-by-step explanation:
Scientists know that the moon reflects light from the Sun through various observations and experiments. One key observation is the phases of the moon, which change as the relative positions of Earth, the Moon, and Sun shift, indicating that the light we see is not coming from the Moon itself, but is reflected sunlight. When people see some objects like the Moon, it's because these objects reflect light. Early astronomers recognized that a full moon occurs when the Moon and Sun are at opposite ends of the sky, suggesting the Moon's illumination is from the Sun.
A simple experiment illustrating this involves using a tennis ball or an orange to represent the moon in a dark room with a bright light acting as the Sun. As you move the ball around your head, which represents Earth, you can observe moon phases similar to what we see in the night sky. Moreover, astronauts have placed corner reflectors on the Moon, which reflects light sent from Earth to measure its increasing orbital distance, further proving the Moon's reflective characteristic.
Additionally, we see similar reflective properties in other astronomical objects like planets, which are visible in our skies solely because they reflect the Sun's light. The amount of light reflected off these planets is significant enough for them to be seen from Earth, just like the Moon, which is much closer to us.