Earth, Moon, and Sun
by Ben McGinnis
The Earth in Space
How Does The Earth Move?
The Earth moves in two different ways. It orbits around the sun and it rotates around its axis.
Earth orbits the Sun is a circular shape. One year is when the Earth makes one whole revolution around the Sun.
The other way Earth moves is when it rotates. There is an imaginary line that goes through the north and south poles which is called an axis. Earth rotates on this axis. This rotation causes day and night.
What causes the cycle of seasons on Earth?
Earth's seasons are caused by the tilt of Earth. The axis always points the same way. When the northern hemisphere is pointing towards the Sun, it is summer for the northern hemisphere and winter for the southern hemisphere. This is flipped when the southern hemisphere is tilted towards the Sun. When neither hemisphere is pointed towards the Sun, it is either spring or fall for the hemispheres.
Gravity and Motion
What is Gravity?
Gravity is the attractive force between objects. The strength of gravity depends on the masses and distance between the two objects. The force of gravity is measured in newtons. This is named after Isaac Newton. Weight is the force of gravity on an object.
What is Inertia and Orbital Motion?
Inertia is the tendency of an object to resist a change in motion. The more mass an object has, the greater its inertia. Isaac Newton stated his ideas about inertia as a scientific law which is called Newton's first law of motion. This law states that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force.
Orbital motion can happen because of inertia and gravity. The moon's orbit around Earth is an example. The gravity of Earth keeps the moon close and the inertia of the moon keeps itself from running into the Earth. With those two factors, the moon stays in a steady, constant orbit around Earth.
Phases, Eclipses, and Tides
What are the Motions of the Moon?
The moon moves through space in two different ways. The moon revolves around Earth and it rotates on its axis. The amount of time it takes the moon to rotate one full time is equal to the amount of time it takes for the moon to make one full revolution around Earth.
What are the Phases of the Moon?
There are 6 different moon phases. A new moon is when the moon is not visible. A full moon is when the whole side of the moon that is facing Earth is visible. There's also a waxing crescent which is when the moon is becoming more visible and the moon is a crescent shape. A first quarter moon is when you can see half of the moon and it is growing. A waxing gibbous is in between a full moon and a first quarter moon. A waning gibbous is the same as a waxing gibbous except the visible part of the moon is shrinking. A third quarter moon is when half the moon is visible and it is shrinking. A waning crescent is the same as a waxing crescent except it is shrinking. Waxing means the visibility of the moon is growing and waning is the opposite.
What are Eclipses?
An eclipse is when an object in space comes between the sun and a third object, it casts a shadow on that object. There are two types of eclipses. there is a solar eclipse and a lunar eclipse. A solar eclipse is when the moon passes directly between Earth and the sun, blocking sunlight from Earth. A lunar eclipse is when Earth blocks sunlight from reaching the moon.
What Are tides?
A tide is the periodic rise and fall of the level of water in the ocean. The gravitational pull of the moon causes the rise and fall of the ocean level. The tides change about every 12.5 hours. There are two different types of tides. There is a spring tide and a neap tide. A spring tide is the tide with the greatest difference between consecutive low and high tides. A neap tide is the tide with the least difference between consecutive low and high tides.
Whats on the Moon's Surface?
The moon's surface has 3 different features. There has craters, highlands, and maria. Craters are large round pits on the moon. Some craters are hundreds of kilometers across. They were originally thought to be from volcanoes but they are actually caused by meteoroids. Highlands are the light colored features on the moon's surface. They are basically mountains. A maria is hardened rock formed from huge lava flows that occurred between 3 and 4 million years ago.
What are the characteristics of the moon?
The moon is dry and airless. The moon is 3,476 kilometers in diameter which is a little less than the distance across the USA. The moon has only one-eightieth as much mass as Earth. The temperature range on the moon's surface is from 266 degrees F to -292 degrees F. The temperature varies so much because there isn't an atmosphere.The moon has no liquid water. There may be large patches of ice near the poles of the moon.
What is the Origin of the MOon
There are many theories of how the moon formed. The best theory is when the solar system was full of Ricky debris. Some of the debris was the size of small of small planets. One of these small planets collided with Earth to form the moon. Material from Earth's surface was ejected into orbit around Earth. Gravity caused this material to combine to form the moon.