ClassX Video Lessons Why Does the Eclipse Move From West to East? Is the Eclipse Going Backward? FreeSchool
Have you ever noticed how the sun and the moon both seem to rise in the east and set in the west? It’s something even beginner sky watchers can see. But during a solar eclipse, something different happens. The moon’s shadow moves from west to east! Let’s find out why this happens.
To understand why the moon’s shadow moves this way, we need to look at how the moon travels around the Earth. If you could look down from above the North Pole, you’d see the moon going around the Earth in a counterclockwise direction. This is the same way the Earth spins and orbits around the sun.
The moon takes about 27 days to go all the way around the Earth. Meanwhile, the Earth spins around once every 24 hours. Even though the moon moves really fast—over 2,200 miles (3,600 kilometers) per hour—it has a much longer path to travel, so it takes more time to complete its orbit.
Even though the moon is moving faster than the Earth spins, the Earth’s quick rotation makes the moon look like it’s moving from east to west in the sky, just like the sun and stars. If the Earth didn’t spin, the moon would rise in the west and set in the east, but it would take almost 14 days to cross the sky!
Imagine you’re on a train moving forward and you see people walking in the same direction. To you, it looks like they’re moving backward, even though they’re walking forward. This is similar to how the moon seems to move in the opposite direction of its actual orbit.
A solar eclipse happens when the sun, moon, and Earth line up perfectly, and the moon’s shadow falls on the Earth. For this to occur, the moon has to be in just the right spot, which is tricky because it’s moving so fast—over 2,200 miles (3,600 kilometers) per hour!
The Earth is about 7,900 miles (12,000 kilometers) wide, and the moon can cover this distance in about three hours. The Earth spins at about 1,000 miles (1,600 kilometers) per hour. Because the moon’s shadow moves quickly, it can cover a large part of the Earth before the Earth has a chance to spin much further.
So, the reason the moon’s shadow moves from west to east during a solar eclipse is because of how fast the moon orbits and how the Earth spins. Understanding this helps us appreciate amazing events like solar eclipses even more!
Shadow Play: Create your own solar eclipse model using a flashlight, a small ball (like a ping pong ball), and a larger ball (like a basketball). In a dark room, use the flashlight to represent the sun, the small ball as the moon, and the larger ball as the Earth. Shine the flashlight on the larger ball and move the small ball between the flashlight and the larger ball to create a shadow. Observe how the shadow moves across the larger ball. Discuss with your friends or family why the shadow moves in a particular direction and how this relates to a real solar eclipse.
Moon’s Journey: Go outside on a clear night and observe the moon’s position in the sky. Note its position at the same time over several nights. Draw a simple map of the moon’s path across the sky. Discuss with your classmates or family how this path relates to the moon’s orbit around the Earth and how it affects the way we see the moon during a solar eclipse.
Train Analogy Exploration: Imagine you are on a moving train and observe objects outside the window. Notice how they seem to move in the opposite direction of the train. Discuss with your teacher or classmates how this is similar to the moon’s apparent motion in the sky. Try to relate this observation to the way the moon’s shadow moves during a solar eclipse.
