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Course: Middle school Earth and space science - NGSS > Unit 2
Lesson 2: The moon and its motionsThe moon and its motions
Review your understanding of the moon and its motions in this free article aligned to NGSS standards.
Key points:
- The moon is Earth’s only natural satellite. It rotates once on its axis and revolves once around Earth about every 27 days.
- A moon phase is the shape of the moon’s sunlit portion as seen from Earth. There are four major moon phases, which repeat every 29.5 days on average.
- The new moon appears completely dark from Earth. This phase occurs when the moon is on the same side of Earth as the sun.
- The full moon appears completely lit from Earth. This phase occurs when the moon is on the opposite side of Earth from the sun.
- The first and third quarter moons both appear half-lit from Earth but on opposite sides. These phases occur when the moon forms a right angle with Earth and the sun.
- A lunar eclipse occurs when the moon is covered by Earth’s shadow. When the moon is partially covered, the eclipse is partial. When the moon is fully covered, the eclipse is total. Lunar eclipses can occur only during a full moon.
Want to join the conversation?
My parents said not to look at the solar eclipse because it will have the same effect when you look at the sun too long. Is that true?(45 votes)
Yes that is true, however looking at a lunar eclipse causes no problems(46 votes)
Why does a lunar eclipse make the moon orange if it is getting covered in the Earth's shadow? Wouldn't it just turn black like the new moon? I am confused.(12 votes)- The body of Earth casts its shadow on the moon, but light hitting the atmosphere is bent around Earth and cast on the moon. The blue end of the light spectrum bends more than the red end of the spectrum. Most of the blue light is bent toward the surface of Earth or up into space, whereas the red light takes a straighter path and ends up on the surface of the moon.
The differential scattering of light that is responsible lunar eclipses looking red is the same physical phenomenon that causes the sky to be blue and sunsets to be red.
Total lunar eclipses aren't entirely red though. The moon will look red near the beginning and the end of the eclipse. But near the middle, when the moon is well within Earth's shadow, the moon looks quite black.(34 votes)
How can the full come every 30 and February has 28 or 29(10 votes)
February is a strange month, but the cycle of the moon will continue unbothered, however every four years there is a 29th day in February, which is known as a leap year.(18 votes)
Why does the moon orbit the earth so much faster than we orbit the sun(12 votes)
Because the moon is much closer to Earth, it will orbit faster. But the Earth is far from the sun so it will orbit longer. Hoped this helped!(10 votes)
- why when the earth spin we don't fill dizzy(12 votes)
Because even though we dont feel it, we move along with it(9 votes)
why does t only occur when the moon is fully coverd and why does luners eclipse only come durning ful moons(6 votes)- The lunar eclipse is when the Earth blocks the sun's light from shining in the moon. For that to happen, the Earth must be between the sun and moon, which is also the position they are in when it is a full moon. There isn't a lunar eclipse every full moon because of the way the moon orbits Earth.(14 votes)
- If the earth spins about 1,000 mph, why don't we go to the other side of the earth when we jump? Thanks.(8 votes)
The earth's spinning speed doesn't affect the wind speed or the gravitational pull on earth. Think of it this way, when your in a car traveling on a road at 60 mph and you through an apple in the air it doesn't go and smash the back window out but if you open the front and back windows it will fly out the back of the car. So I'm also thinking that the atmosphere has a play in this to.(9 votes)
- Why doesent gravity pull the moon closer and closer but it moves other objects like meteroids into our atmosphere.(7 votes)
- Because there are two vectors working on the Moon. There is the gravitational force vector pointing from the Moon to Earth and the Moon's velocity vector which is roughly perpendicular to that. Without Earth's gravity, the Moon would fly off into space. without the Moon's velocity, then the Moon would crash into Earth. The two combined have the Moon orbiting Earth. Gravity has the Moon constantly falling toward Earth but its velocity ensures that it always misses.
This interplay of gravity and velocity is the same reason why Earth doesn't collide with the Sun.(9 votes)
why the full only comes on 30?(8 votes)
The full moon comes about every 29 and a half days. It comes that frequently because the moon orbits the earth about every 27 days, but the earth’s spinning, and it and the moon are also orbiting the sun. This all works out so that the moon repeats its phases every 29.5 days.(8 votes)
- whys it callde the blood moon(7 votes)
it turns a reddish color. look out for them! they look really cool!(5 votes)
