Here's a breakdown of the sizes of Earth, the Moon, and the Sun:

Earth:

* Diameter: 12,742 kilometers (7,918 miles)

* Circumference: 40,075 kilometers (24,901 miles)

Moon:

* Diameter: 3,474 kilometers (2,159 miles)

* Circumference: 10,917 kilometers (6,784 miles)

Sun:

* Diameter: 1,392,684 kilometers (865,000 miles)

* Circumference: 4,370,008 kilometers (2,714,000 miles)

Perspective:

* The Sun is 109 times wider than Earth.

* The Sun is 400 times wider than the Moon.

* Earth is 3.7 times wider than the Moon.

It's also helpful to consider the relative volume (the amount of space something takes up):

* The Sun contains 1.3 million Earths.

* Earth contains 49 times more volume than the Moon.

These numbers give you a sense of just how vast the universe is, and how comparatively small our own planet is.