The Moon’s Motion in the Sky

(notes)

The Moon rotates on an axis(it spins like a top)

• The Moon has a very slow rotation, about 28 days. (Our rotation is 24 hours)

• The Moon also orbits the Earth. It takes 28 days to orbit the Earth.

• The Moon’s very slow rotation, along with its orbit around the Earth, means that we only see one side of the Moon—EVER!

• The only way we have seen the back side of the Moon is when we have sent a space probe or when we have gone to the Moon.

Let’s watch a video on that…

• http://www.youtube.com/watch?v=OZIB_leg75Q

So…we see Moon phases• We see different lit-up areas of the Moon,

based on where the Moon is around us and how the Sun is shining on it.

• Please see Figure 28.18 and 28.19 on pages 762 and 763.

• I *WILL* have a question or two over that on the test, so you should learn these.

• In just a couple of minutes, we will do a lab that will help us see these moon phases.

• But first….

Let’s talk about Eclipses, while we are at it…

• Eclipses are when either the Moon falls into the Earth’s shadow (Lunar Eclipse) or when the Earth falls into the Moon’s shadow (Solar Eclipse).

• I think the picture on page 765 is VERY confusing, so look at these two pictures on the next two slides.

Solar Eclipse

Lunar Eclipses

Things you need to know about Eclipses…

• Eclipses do NOT happen every month, because the Moon’s orbital path around Earth is tilted a little over 5 degrees from our path around the Sun (called the Ecliptic).

Things to know…continued.

• Only every once in a while does everything line up perfectly so that we have a Solar or Lunar Eclipse.

• Nasa.gov has a listing of when every eclipse is, if you are interested in seeing when the next one is.

• So…solar and lunar eclipses and Moon phases…our Moon is pretty amazing!

The Moon…(The End)