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Earth, Moon, and the Sun

Earth shades the Moon

Now put Earth between the Sun and the Moon. What happens to the Moon?

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The idea

Full Moon is when Earth is between the Sun and the Moon. They are nearly in a row.
Step 1 of 4
  1. Full Moon is when Earth is between the Sun and the Moon. They are nearly in a row.
  2. Earth's shadow stretches out behind it.
  3. The shadow falls on the Moon and can cover it whole.
  4. Earth is more than three times as wide as the Moon.

The rule

Earth's shadow falls on the Moon and darkens it.

In a lunar eclipse Earth is between the Sun and the Moon. Earth shades the Moon.

  • The Moon fully in the shadow is a total lunar eclipse. It often looks dark red.
  • The Moon partly in the shadow is a partial lunar eclipse.
The same idea, with the order swapped
Moon in the middleEarth in the middle
We call itA solar eclipseA lunar eclipse
Moon's place on its tripNew MoonFull Moon
Shadow lands onA small patch of EarthPart or all of the Moon
Safe to look atNever directlyYes, with your eyes alone

A lunar eclipse can be seen from a large part of Earth.

Jump to lesson

This track

  1. 0 Start here
  2. 1 Earth is doing two things at once
  3. 2 The Moon keeps one face turned to us
  4. 3 When three line up, one shades another
  5. 4 The Moon shades a patch of Earth
  6. 5 Earth shades the Moon
  7. 6 Why it is not every month
  8. 7 One is safe to watch, the other never is
  9. 8 Checkpoint: motions, the Moon and eclipses
  10. 9 Why the Sun seems to move
  11. 10 Day here, night there
  12. 11 The star that stays still
  13. 12 Checkpoint: the turning sky
  14. 13 The night sky changes through the year
  15. 14 The tilt makes the seasons
  16. 15 The longest and shortest days
  17. 16 Checkpoint: the year, the tilt and the seasons
  18. 17 The big picture
  19. 18 Track quiz

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