People think the moon looks bigger when it’s near the horizon. It’s true. The moon does look bigger near the horizon.

Usually, when we see the moon, it’s up in the sky, away from the horizon.¹After all, the moon is only 1/2 degree angular diameter, yet the Earth rotates about 360 degrees every day. If the moon is visible, odds are, it’s not near the horizon. If it appears by a tree, it’s a close tree, maybe the tree in the neighbor’s yard. The moon looks small in comparison, like a basketball in the limbs. This is how we’re used to seeing the moon.

When the moon is near the horizon, it could appear by a tree miles away. The tree appears much smaller, yet the moon is the same size. Instead of being the same size as a basketball in the limbs, it looks nearly as large as a tree.

Our brains interpret this as a larger moon, rather than a smaller, father away tree.

The following two pictures illustrate this illusion. The size of the moon in both pictures is the same.

Does the moon look larger to you near the horizon?

• 1
  After all, the moon is only 1/2 degree angular diameter, yet the Earth rotates about 360 degrees every day. If the moon is visible, odds are, it’s not near the horizon. ↩︎