Sun, Moon and Earth Orbits

          To know that the Earth orbits the Sun once a year and that the moon takes approximately 28 days to orbit the earth. To know that the Earth spins on its own axis once every 24 hours. As the moon goes through its phases, it looks a little different each night, ranging from not there at all to full. Your group will act out how the sun illuminates the moon as it orbits. Earth, to understand how the moon moves through its phases.

            The moon shines because it is reflecting the sun. So why doesn't it always look the same. As it travels around Earth, the half of the moon facing the sun is always "lit up." When we see depends on where the moon is in orbit, and the relative positions of Earth and the sun. When it is a new moon, the moon is between Earth and the Sun with its bright side facing the sun and its dark side facing Earth. When the moon is full, and we see a full circle of light in the sky. Earth is between the moon and the sun, the moon's bright side is facing us. It helps to look at a diagram to fully understand the phases of the moon and there is a good one at Clear Skies on Demand.

                          Earth's moon is the fifth-largest moon in the Solar System and is the largest natural satellite of a planet (the moon is about one-quarter the size of earth). When it first formed, the moon was probably much closer to earth, and spun around much faster than it does now. Earth's gravity, pulling on the moon, has gradually slowed it down so that now the same side of the moon is always facing the earth. The surface of the moon is like a rocky desert. Like earth's rocks, most moon rocks are made of silica, a combination of silicon and oxygen atoms. The surface of the moon also contains many mountains and craters. The moon's sky looks black, because there is no atmosphere to reflect the sunlight and make it seem blue.

                            The most noticeable effect the moon has on the earth is the rise and fall of the ocean tides. The curved shape of both the earth and moon, along with the moon's orbit, make the moon's gravitational pull stronger on one side of the earth than the other. The earth rotates on a 23 degree axis, which means it's tilted a little to the side. The axis is kept relatively stable by the moon's gravitational pull. Without the moon's influence, scientists believe that the earth's axis would shift as much as 85 degrees.

                              The moon has no light of its own, instead, it reflects the light of the sun. Depending on where the moon is and where the sun is and where a person is on earth, he may be able to see all of the side of the moon that's lit up by the sun called a full moon or he might only be able to see a tiny silver of the part of the moon that's lit up by the sun called a new moon. It takes about a month for the moon to get all the way around the earth, which takes us through all the 'phases' of the moon from one full moon to the next.