Learn the differences between our Earth, the Sun and the Moon. Then explore how together they create day and night and our different seasons with their orbits.

Let's say we want to build a model of the sun and Earth alone. Earth has a radius of about 6,371 kilometers (3,959 miles), but let's represent this with a marble 1 centimeter in diameter.

In regards to mass, the moon has roughly 1.2% of Earth's mass. When is the moon closest to Earth? ... During eclipses, the moon, Earth and sun are in a straight line, or nearly so.