Not the Earth's shadow
Phases and eclipses are different things.
A common belief
Many people say the Moon's phases happen because the Earth's shadow falls on the Moon.
Is that the right explanation?
What this lesson covers
The idea
The Moon's phases are caused by the changing relative orientation of the Sun, Moon and Earth, not by Earth's shadow; Earth's shadow falling on the Moon causes a lunar eclipse.
A common belief
Many people say the Moon's phases happen because the Earth's shadow falls on the Moon.
Is that the right explanation?
- No, phases come from the changing orientation of Sun, Moon and Earth
- Yes, it is the Earth's shadow
- Yes, it is clouds
Phases or eclipse
Tap the bin where each statement belongs.
Two different causes
The Moon's phases happen because the relative orientation of the Sun, Moon and Earth changes as the Moon goes round the Earth. When the Earth's shadow falls on the Moon, a lunar eclipse happens.
Phases: changing orientation of the Sun, Moon and Earth. Lunar eclipse: Earth's shadow on the Moon. Phases are not due to Earth's shadow.
Notes
Phases are not the Earth's shadow. The Earth's shadow on the Moon makes a lunar eclipse.
Check yourself
The phases of the Moon are caused by …
The Earth's shadow falling on the Moon causes …
Which statement is correct?
A lunar eclipse is …
- the changing orientation of the Sun, Moon and Earth — correct. Yes!
- the Earth's shadow on the Moon. That causes a lunar eclipse, not the phases.
- clouds. Clouds do not cause the phases.
- the phases. Phases do not come from the Earth's shadow.
- a lunar eclipse — correct. Yes!
- new Moon. New Moon is a phase, not an eclipse.
- Phases are caused by the Earth's shadow. That is an incorrect explanation.
- Eclipses cause the phases. Phases and eclipses are different.
- Phases are not caused by the Earth's shadow — correct. Yes!
- rare and brief — correct. Yes!
- a daily event. Eclipses are rare and brief.
- the same as a new Moon. They are different things.