The Moon, Earth, and Sun
by Shawn Hamilton
The moon has many phases from a new moon to a full moon and back. The moon rises and sets just like the sun even though it might not be visible every night. Clouds or rain can be an obstruction to sighting the moon.
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The first phase of the moon, the one that starts a fresh cycle, a new moon. A new moon occurs when the moon's orbit is closest to the sun, or have the same ecliptical longitude, as seen from Earth. It is hardly visible because the enlightened side, the side the sun hits, is facing away from Earth. A new moon rises and sets with the sun making it out during the day. A new moon marks the beginning of a new cycle.
Waxing and Waning Gibbous
Waxing and waning gibbous are phases between a full moon and a half moon. Waxing means to become larger or stronger, so the moon is getting bigger during this phase. Waning means to progressively get smaller, so the moon is getting less visible during this phase. Gibbous is when the moon is more than half, but not completely full.
Waning and Waxing Crescents
Waning and Waxing Crescents are like the waning and waxing gibbous with the meanings of waning and waxing, but it's not when the moon is more than half full. A crescent is less than half, but not a new moon, so even if it's just a sliver, it's still a crescent moon. Waning crescents are after the latest half moon, leading into the new moon. Waxing crescents are after a new moon leading into a half moon.
A full moon occurs when the moon is on the opposite side of the Earth as the sun. The sun's rays cover the side of the moon that is visible from Earth allowing us to see the entire moon. A full moon only happens once per moon cycle and at the opposite end of the moon cycle as a new moon.
Earth in Space
How Earth Moves
How does the Earth move in space?
Earth rotates around a slightly tilted axis spinning in a rotation. The rotation causes day and night; when the rotation faces the sun, it's day, when it faces away from the sun, it's night. One rotation is a 24-hour day cycle. Along with the Earth rotating, it's orbiting around the sun. One revolution around the sun is a year. Earth orbit is not circular, but more ellipse.
What causes the cycle of seasons on Earth?
As you know, Earth has a tilted axis. Well that tilt can be facing the sun, facing away from the sun, or neutral with the sun. The sun emits sunlight and the sunlight hits the Earth. The sunlight hits the Earth more directly at the equator, making the equator very hot. As for Antarctica, the sunlight hits it more spread out because of the curve of the Earth making it cooler up there. The Earth's tilted axis making one hemisphere receive more sunlight during certain times. In July in the northern hemisphere, it's warm because it's tilt is facing the sun, while as for the southern hemisphere, it's winter because it's tilt is facing away from the sun. The cycle of the seasons on Earth is basically caused by the tilted axis while revolving around the sun. During spring and fall, neither the northern or southern hemisphere is facing the Earth. An equinox are the two days of the year of which neither hemisphere is toward or away from the sun. A solstice are the two days of the year on which the sun reaches it's greatest distance north or south of the equator.
Gravity and Motion
What determines the strength of the force of gravity between two objects?
Gravity is a force that attracts all objects to each other. Isaac Newton created the law of universal gravitation which states that every object in the universe attracts every other object. Force of gravity is measured by newtons named after Isaac Newton. The strength of the force of gravity is dependent on the mass of the objects and the distance between them. Mass is the amount of matter in an object. Weight is the force of gravity on an object. On the moon, you weigh one-sixth of your weight on Earth the gravity on the moon is weaker.
Inertia and Orbital Motion
What two factors combine to keep the moon and Earth in orbit?
The first law of motion created by Isaac Newton states that an object in motion will stay in motion with a constant speed and direction unless acted on by a force. This law was based on inertia. Inertia is the tendency of an object to resist change in motion; when people get whiplash from car crashes, its because when the car suddenly stops, you don't stop with it, but your seat belt holds your body back causing your head to thrust forward. Newton made a conclusion that inertia and gravity combined keep Earth in orbit around the sun and the moon around the Earth. Gravity pulling the moon from Earth prevents it from moving in a straight line. Inertia keeps the moon moving forward and gravity pulling it towards Earth concludes to an orbit.
Phases, Eclipses and Tides
Motions of the Moon
Along with the Earth, the moon rotates on its axis and revolves in orbit at the same time. The position of the moon from Earth to the sun changes. The changing relative positions of the Earth,Sun, and moon cause the phases of the moon, eclipses, and tides. The moon rotates around its axis in the same amount of time as it revolves around Earth, making one day equivalent to a year, also limiting us to only seeing one side of the moon.
Phases of the Moon
What causes the phases of the moon?
The moon in the sky can be different shapes, each of which is a different phase. The moon goes through a revolution of phases called the moon cycle. The cycle goes new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent, and then back the new moon Phases are caused by changes in the relative positions between the Earth, Sun, and moon. Half of the moon is always lit by the sun, but on Earth, we don't always see that side. Sometimes we see half of it, sometime not even a sliver. The phase of the moon we see is dependent on how much of the sunlit side of the moon is facing towards Earth.
What are solar and lunar eclipses?
An eclipse is the partial or total blocking of one object in space by another. An eclipse occurs when the moon's shadow hits Earth or the Earth's shadow hits the moon. The two types of eclipses are lunar and solar, deriving from the Latin words for moon and sun. A solar eclipse is when a new moon blocks sunlight from hitting the Earth. A lunar eclipse is when Earth blocks sunlight from hitting the moon. An umbra is the darkest part of the moon's shadow upon Earth. The umbra appears during a solar eclipse; while in the umbra, everything is dark and an eerie color. A penumbra is the larger part of the moon's shadow. While in a penumbra, you can only see a partial eclipse.
What causes the tides?
Tide is the periodic rise and fall of the level of water in the ocean. Tides are caused mainly by the difference in how much the moon's gravity pulls on different parts of the Earth. For example, if the moon is directly above the coasts of South Carolina, the pull of gravity is going to create high tides, and if the moon was almost done setting from the point of view of South Carolina, then the tides are slowly going to lower. There are always two high tides at the same time, where the moon is above, and on the opposite side of the world.A spring tide is the tide with the greatest difference between consecutive low and high tides. A tide with the least difference between consecutive low and high tides is a neap tide.
The Moon's Surface
What features are found on the moon's surface.
The moon's surface has many feature including maria, craters, and highlands. Maria in Latin means seas.