|Outside, my mother and I were watching the blood
moon of April 15, 2014. The moon is (looks) like
it is behind a tree. When it came from behind the
clouds, it looked like it lifted. How is this? Is
it true? How often is it? Why?
A lunar eclipse happens when the moon enters
the Earth's shadow, i.e. the Earth is between the
moon and the sun. This casts the moon into
darkness because it no longer has the sun to light
it up. Because the moon is in orbit around the
Earth, the moon's entering the Earth's shadow is a
temporary thing, and every so often will move out
The moon (as well as the sun, and the rest of
the stars in the sky) appears to change its
position in the sky because of the way the earth
rotates around an invisible axis that is slightly
tilted from from the line that would go from the
north pole to the south pole. To help you see why
this is true, take a balloon and draw a dot on one
side of it. Image the dot is where you are
standing on the earth. Then, shine a flashlight on
the balloon. Spin the balloon and you will see
that the side of the balloon with the dot will
alternately be lit up and then be dark. From the
point of view of the dot, it looks like the light
is "rising" and "setting" -- just like the moon,
sun, and stars appear to rise and set for us!
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