Quck answer
The Moon changes shape because of its position in relation to the Earth and the Sun. As the Moon orbits around the Earth, different amounts of sunlight illuminate its surface, creating different phases. When the Moon is between the Earth and the Sun, we see the side of the Moon that is not illuminated, resulting in a New Moon. As the Moon moves further along its orbit, more of its illuminated side becomes visible, leading to a Waxing Crescent, First Quarter, Waxing Gibbous, and eventually a Full Moon. After that, the illuminated side gradually decreases, causing a Waning Gibbous, Third Quarter, Waning Crescent, and back to a New Moon again.
The Moon has always captivated people’s interest and for good reason. It influences our tides, causes solar eclipses, and seems to have a face. Adding to its allure, the Moon undergoes changes in shape!
If you have ever spent time observing the Moon, you would have noticed that its shape varies from one night to the next. Sometimes it appears to shrink, while other times it appears to grow. We are all aware that the Moon changes shape, but have you ever wondered why?
The shape we see is determined by the Moon’s position. As the Moon orbits around the Earth, it reflects sunlight. From our perspective on Earth, we can only see the part of the Moon that is facing us. Therefore, the shape of the Moon that we observe on a given night depends on the amount of the Moon’s face that is illuminated by sunlight at that particular point in its cycle.
The different shapes of the Moon are known as phases. These phases occur throughout the Lunar Cycle, which lasts approximately 27 days. At the beginning of the Lunar Cycle, the Moon is positioned between the Earth and the Sun. During this phase, the side of the Moon that reflects sunlight is facing away from Earth, rendering the Moon invisible to us. This phase is referred to as the New Moon.
As the Moon continues its revolution, we gradually see more of it each night. This period is known as the “waxing” phase, during which the Moon appears to grow larger. It initially appears as a crescent, resembling a small curved shape in the sky. However, the entire Moon is still present; we can only see the portion that is reflecting sunlight due to its position in its orbit.
Around the midpoint of the Lunar Cycle, the Earth is positioned between the Sun and the Moon, allowing us to see the Moon’s entire illuminated face at night. This is known as a Full Moon. Occasionally, during a Full Moon, the Earth casts a shadow over the Moon’s face, resulting in a Lunar Eclipse.
Following the Full Moon, the Moon appears to shrink in size. As it nears the end of its revolution, we see less and less of it each night. This period is referred to as the “waning” phase, indicating that the Moon is getting smaller. Towards the end of the cycle, the Moon once again appears as a crescent in the sky. Eventually, the Moon completes its revolution, and the cycle begins anew with a New Moon.
Have you ever heard about the “dark side” of the Moon? Many people believe that this side of the Moon never receives sunlight. However, that is not true. As the Moon orbits around the Earth, it also rotates on its own axis, similar to the Earth. However, the Moon’s rotation is much slower than that of the Earth. It takes the same amount of time for the Moon to rotate as it does to complete one revolution, which is roughly 27 days. Since the Moon rotates at the same speed as it revolves, the same side always faces Earth. The side we never see is referred to as the dark side of the Moon. It is called “dark” because it is not visible from Earth, but it does receive sunlight, just like the rest of the Moon!
Have you ever observed the Moon change its shape? How about the motion of the stars? The night sky can be captivating if you pay close attention to it. The next time you find yourself outside on a clear night, make sure to look up! You might just witness something new!
Give It a Try
Find a friend or family member who can assist you with the following activities!
- Are you having trouble visualizing how the Moon’s revolution affects its shape? Take a look at this explanation from NASA. Afterward, explain to a friend or family member how the Moon’s phases work.
- Do you enjoy stargazing? Start a Moon journal! Each night, draw what the Moon looks like. Add labels to each sketch indicating the Moon’s phase. Is it a new moon or a full moon? Is the Moon waxing or waning?
- Do you dream of a future where space travel is accessible to everyone? Imagine that you are planning a trip to the Moon! What will you bring with you? What activities will you engage in there? Write a story about an adventure you could have during your trip.
Sources of Wonder
- https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question3.html (accessed 11 Feb., 2019)
- https://www.space.com/18880-moon-phases.html (accessed 11 Feb., 2019)
- https://www.nationalgeographic.com/science/space/solar-system/full-moon/ (accessed 11 Feb., 2019)
Leave a Reply