Lunar eclipse

The idea

A lunar eclipse occurs when the Earth comes between the Sun and the Moon and blocks sunlight from reaching the Moon, so the Earth's shadow falls on the full disc of the Moon.

A shadow on the full Moon

Sometimes the bright full Moon turns dim and dark.

What do you think hides the light of the Moon?

• The shadow of the Earth
• A big cloud
• The shadow of Venus

Put the Moon in the shadow

Move the Moon round the Earth. The picture is not to scale.

The Earth in the middle

When the Earth is between the Sun and the Moon, it blocks sunlight from reaching the Moon. Unlike the Sun, an eclipsed full Moon can be watched safely with the naked eye.

A lunar eclipse occurs when the Earth comes between the Sun and the Moon and blocks sunlight from reaching the Moon, so the Earth’s shadow falls on the full disc of the Moon.

Notes

A lunar eclipse occurs when the Earth comes between the Sun and the Moon and blocks sunlight from reaching the Moon, so the Earth’s shadow falls on the full disc of the Moon.

Check yourself

In a lunar eclipse, which comes between the Sun and the Moon?

In a lunar eclipse, whose shadow falls on the Moon?

Can an eclipsed full Moon be watched with the naked eye?

In which order are the three in a lunar eclipse?

• A big cloud. Clouds are in the Earth’s air. They do not cause an eclipse.
• The planet Venus. Venus is too small and too far to block sunlight from the Moon.
• The Earth — correct. Yes! The Earth blocks the sunlight.
• The Earth’s shadow — correct. Yes! The Earth’s shadow falls on the full disc of the Moon.
• The Moon’s own shadow. In a lunar eclipse the Earth’s shadow falls on the Moon, not the Moon’s own.
• The shadow of Venus. Venus is far too small to cast a shadow like that on the Moon.
• No, it always harms the eyes. Unlike the Sun, the eclipsed full Moon can be watched safely.
• Yes, it is safe to watch — correct. Yes! Only the Sun is dangerous to look at.
• Only with special eye protection. Special eye protection is needed for watching the Sun. The eclipsed full Moon can be watched with the naked eye.
• Sun, Moon, Earth. That is the order in a solar eclipse.
• Earth, Sun, Moon. The Earth is between the other two in a lunar eclipse.
• Sun, Earth, Moon — correct. Yes! The Earth is in the middle.