Have you ever looked up in the night sky? What did you see? The stars? What else? How about the moon?
Did you ever wonder about the moon? What is it? How did it come to be? Why does it change shape and size every month? What is it made of?
To answer all these questions, let’s begin with how that moon formed. This is a question with no simple answer. There are many theories about this. One of the most popular is that about 3.5 to 4.5 billion years ago, about the time the Earth was formed, a meteor the size of Mars hit the Earth, creating the moon. Another theory is that the moon is actually a trapped asteroid that got stuck in the Earth’s atmosphere. Yet another theory is called the fission hypothesis. The fission hypothesis states that when the Earth was first formed, it was spinning faster than it does today. As it was spinning, part of the Earth’s crust split off and drifted away, thus becoming the moon.
So, what exactly is the moon, and what is it made of? The moon is an egg-shaped satellite of the Earth. It has a dusty, rocky surface. There are many craters, valleys, lava plains, and mountains on its surface. Scientists believe that the craters were made by meteors slamming into the moon about 3.5 to 4.5 billion years ago.
The moon has no wind or weather and no air or atmosphere, meaning that it can’t hold in heat from the sun, or cool from the darkness. It also has no global magnetic field. It has about 1/6 the gravity that the Earth has. Since there is no air or atmosphere on the moon, it’s temperatures are extreme and vary greatly. The temperature during the moon’s day, which is two weeks long, is +300 degrees F, and the temperature during the two week night is -270 degrees F. Because there’s no wind, the footprint that Neil Armstrong left on its surface during his historical moon walk will still be there about ten million years from now.
The moon is about 238,000 miles from the Earth. It is ¼ the size of Earth. Even though it is smaller, its surface is about 9.4 billion acres. The moon orbits the Earth in an elliptical or flattened oval position. It rotates counterclockwise. The moon orbits the Earth at the speed of about 2,300 miles per hour. While it is orbiting the Earth, the moon itself is also rotating. It rotates at the speed of about 10 miles per hour. Compared to the Earth’s rotation speed of 1000 miles per hour, the moon is very slow. Although it rotates as it orbits, we really only see one side of the moon. The moon takes 27.3 days to completely orbit the Earth one time.
Some of the things we know about the moon are due to lunar landers sending photos back to Earth and astronauts walking on the moon and exploring it. The first pictures of the moon were captured by The Soviet Union’s craft, Luna 3 on October 1959. The first man to walk on the moon was Neil Armstrong, an American astronaut, in July 1969. He and another astronaut, Edwin “Buzz” Aldrin spent about 2 ½ hours outside the lunar lander known as Apollo II, testing the gravity, exploring, and planting the U.S. flag on the surface of the moon.
So, why does the moon seem to change size and shape about every month or so? The moon’s shape appears to change because of its position in relation to the sun. The moon reflects light from the sun. The size and shape change is called moon phases. There are eight phases of the moon:
The New Moon is the time when none of the moon is visible.
The Waxing Crescent is when you can see a crescent shaped moon is visible. The crescent will face to the left if you live in the Northern Hemisphere, and right if you live in the Southern Hemisphere.
The First Quarter Moon is when you can see about ½ the moon.
The Waxing Gibbous is when you can see ¾ of the moon.
The Full Moon is when you can see all of the face of the moon.
The Waning Gibbous is when the moon is after the full moon, you can see ¾ of the moon again.
The Last Quarter Moon is when you can see ½ the moon again.
The Waning Crescent is when the moon returns to the crescent shape, either pointing to the right if you are in the Northern Hemisphere or to the left in the Southern Hemisphere,
So, why during the crescent moons do they point in opposite directions in the Northern and Southern Hemispheres? It is because we are basically “upside down” from each other.
When the visible part of the moon is growing larger, it is a waxing moon, when it is getting smaller, it is a waning moon. The full moon is a lunar phase that occurs when the moon is on the opposite side of the Earth from the sun and all three are aligned. There is no full moon in the month of February.
During the phases of the moon, it rises and sets at different times. The First and Last Quarter Moon rises mid-morning and sets midnight. The New and Full Moon rises and sets with the Sun.
The moon even affects the ocean tides. This is due to the gravitational force of the moon and the Earth. The tidal ranges are at their peak during the full moon. These tides are called spring tides. When the moon, sun and Earth are at right angles, the neap tides are formed.
There are several studies of human behavior during a full moon. It is believed that the full moon affects behaviors in humans during this time. There seems to be an increase in criminal behavior, doctor visits, increased agitation, and even the number of babies born when there is a full moon.