While we performed Activity 1, you might remember that you had to hold the model of the Moon a little above your head or bend a little so that you do not block the light from the Sun. Does the Earth block sunlight or does it not? If it does, how do we see the full Moon?

Well, most of the time it doesn’t block the light because the Moon’s orbit is not in the plane of the Earth’s orbit. The plane of the Moon orbit makes an angle of 5^° to the plane of the Earth’s orbit. Figure 3 shows an oblique view to the Sun-Earth-Moon system. The Earth is shown at position A and two snapshots of the Moon’s orbit are shown at A and B (the Earth is not shown at position B for the sake of clarity). As you can see, the orbit of the Moon makes and angle of 5^° at any given point. So even when the Moon and the Sun are on the side of the Earth or on exactly opposite sides of the Earth, the angle between the Sun-Earth line and the Earth-Moon line can vary between 0° and 5^°. Let us understand this in more detail with an activity.