WONDER · Everyday questions
Why does the Moon follow our car?
The trees rush past the window. The houses disappear behind you. Yet the Moon seems to stay beside the car. If your child asks whether it is following you, here is a gentle place to start.
The short answer to share
“The Moon isn’t following our car. It is so far away that, as we travel, the direction we look to see it changes only a little. Nearby trees look as though they rush past, but the faraway Moon seems to come along.”
Why distance makes a difference
When your position changes, nearby things appear to shift more than distant things. This change in viewpoint is called parallax. The Moon is about 384,400 kilometres from Earth on average—far beyond the buildings or hills outside your window.
The Moon is moving in its own orbit. That movement is different from the “following us” effect during a short car journey. NASA’s Moon facts explain its distance and orbit.
Try this at home
Hold your thumb up at arm’s length with a picture or doorway in the distance behind it. Close one eye, then switch eyes, keeping your head and thumb still. Your thumb appears to jump against the background.
Now bring your thumb a little closer and repeat. The apparent jump becomes bigger. Your thumb has stayed still; your viewpoint has changed. This is the idea explored in NASA’s parallax activity.
A question for the next journey
Invite your child to notice which things seem to pass quickly and which seem to stay nearby. A passenger can compare a close lamp post with a distant hill; the driver should keep their attention on the road.
Then explore another sky question together: why doesn’t the Moon fall?
