Here's why:

* Size: The Sun is a star, a giant ball of hot gas. It's about 109 times wider than Earth and about 333,000 times more massive. The Moon, on the other hand, is a relatively small rocky body, only about one-quarter the size of Earth.

* Distance: Even though the Sun is much larger, it appears smaller in the sky because it's much farther away from Earth than the Moon. The Moon is a mere 238,900 miles away, while the Sun is 93 million miles away.

So, although the Moon appears to be the same size as the Sun in the sky, it's only an illusion caused by the difference in distance.