Earth, Moon, and Sun
By, Skylar Laidman
Earth in Space
Every year the Egyptian eagerly waited for the Nile River to flood. For thousands of years, their planting was ruled by the flood of the Nile. So the Egyptian farmers had to be ready at all times. Around 3000 B.C. people noticed that the bright star Sirius first became visible in the early morning sky every year soon be for the floods of the Nile. The Egyptians used this knowledge to predict when the flood will happen. Because of this discovery the ancient Egyptians were one of the first to discover astronomy.
The line down the center of the earth, between the north and south poles is the earths axis. The earth spins tilted on it's axis in rotation, twenty-four hours is equal to one full rotation. In addition to rotating the earth travels around the sun, which is called a revolution. A full revolution is 365 days which equals a full year. At the beginning of every new year we complete one full rotation around the sun, which we call an orbit.
Stonehenge was one of the first calendars in use. A calendar is a system of organizing time that defines the beginning, length and division of a year. The Roman's borrowed from the Egyptian calendar of 365 days. But in fact, earth's orbit is about 365 1/4 days. The Roman's adjusted their calendar by adding one day, every fourth year. This is also known as "Leap Year". During Leap Year, February is given 29 days instead of 28 days. Using a system of Leap Year ensures that the constant day of celebration, for example the beginning of summer, occurs on the same date each year.
When the sun is the farthest south or north of the equator it is called a solstice. This solstice occurs around June 21st every year, which is the longest day of the year in the northern hemisphere and the shortest day in the southern hemisphere. Near December 21st, the sun is farthest south of the equator so this is the summer solstice in southern hemisphere and it is the winter solstice in the northern hemisphere.
Half way between the solstice neither hemisphere, southern or northern are tilted toward or away from the sun. This will occur twice a year when the noon sun is directly above the equator. When each of these days occur we call it an equinox, which means "equal night". During the equinox, day and night are about twelve hours long everywhere on earth, in each time zone. The vernal "spring" equinox occurs around March 21st and marks the beginning of spring in the northern hemisphere. The autumnal "autumn" equinox occurs around September 22nd, which marks the beginning of fall in the northern hemisphere.
Key Concept Questions:
1.) Q>What are the two major motions of Earth as it travels though space?
A>Earth's revolution and rotation.
Q>Which motion causes day and night?
A>Rotation because the Earth spins on its axis allows some light to reach all parts of the Earth.
2.) Q>What causes the seasons?
A>The Earth revolution around the sun.
Q>What are solstices and equinoxes? How are they related to the seasons?
A>Equinoxes are the half way point between the seasons, also known as
spring and fall.
Q>How would the seasons be different if Earth were not tilted on its axis?
A>There would be no season because there would be no change in distance from
Gravity and Motion
The force or pull/push that keeps us on earth is called gravity. Gravity is why we aren't flying though the air right now. Okay who knows who discovered the idea of gravity? How about you way in the back with the eyes (that was a joke you can laugh now). But seriously if you don't know who Isaac Newton you need to slap you science teacher. Isaac Newton created the idea of the law of universal gravitation, witch is states that every object in the universe attracts every other object. Okay what are we other then humans? We are mass. Mass is the amount of matter in an object. if gravity pulls us to the earth weight is the force of gravity. Also if there is more mass then there is more gravity pushing it down so that is why people weigh more or weigh less then others. Inertia this weird word mean the tendency of an object to resist a change in motion. Basically you feel this every day . When you are riding in a car and it suddenly stops and you keep moving forward. if you did not have your seat belt on you could hit the item in front of you depending on where you are in the car that is inertia. Now then back to newton he also discovered the Newton first law of motion witch says an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction un less acted on by a force.
Key Concept Questons
1. Q> What is the law of universal gravitation?
A> States that every object in the universe attracts every other object.
Q> What two factors determine the force of gravity between two objects?
A> Mass and weight.
Q> Suppose the moon were closer to Earth. How would the force of gravity between Earth and the Moon be different?
A> The oceans current would be different since the moon controls the oceans movements. Because of inertia, the moon stays in one place instead of floating off into space or crashing into Earth or the Sun.
2. Q> What two factors work together to Earth orbiting around the Sun?
A> Combination of gravity and inertia.
Q> Why doesn't Earth simply fall into the Sun?
A> Because the Earth and Sun's gravity forces them away from each other, the Earth stays in orbit along with the other planets.
Q> How would earth move if the Sun "including it's gravity" suddenly disappear.
A> The Earth would stop in it's orbit immediately because it has no gravity to pull or push it away from meteorites, other planets, and Suns.
Phases, Eclipses, & Tides
Ever notice how the Moon changes shape? It isn't actually changing. The different shapes are actually what we call Phases. A Moon phase is one of the different apparent shapes of the Moon as seen from your human eyes, on Earth. The Moon goes through a whole set of phases each time it completes a revolution around the Earth. The phases of the Moon are caused by different positions of the Earth, Moon, and Sun. When the Sun's light shines on the Moon, you only see the parts that the sunlight is hitting, which gives us the impression of a shapes and phases.
If the Moon sits between the Sun and the Earth it causes an Eclipse. An Eclipse is the partial or total blocking of one object in space by another object. An eclipse can be caused by any space debris, asteroids, comets, and meteorites. There are two types of eclipses. "The words Solar and Lunar come from the Latin language, as solar meaning sun and lunar meaning moon." During a solar eclipse, the darkest part of the moons shadow is called an Umbra. Umbra is shaped like a cone and forms a fine point at the tip. The umbra blocks out sunlight inside the cone shape which points at Earth with the tip. It causes a small circle of darkness that blocks light on Earth. During a Penumbra, the people standing in this part see a partial eclipse. The sun gets extremely bright so you shouldn't look at it because it is so powerful. A Lunar eclipse happens only when there is a full moon because the Moon is closest to the Earth's shadow. In a lunar eclipse the Earth is directly between the Sun and the Moon. In this type of eclipse the umbra is the shadow being cast by the Earth. A total solar eclipse is rare because the sun is completely blocked by the moon and it causes complete darkness.
Have you ever been to a beach on the ocean and wrote your name in the sand? Then have it get washed away by the water? Those are tides, that move in and out about every six hours. High tide is when it is at it's highest level on the sand and low tide is when the water is at it's lowest level on the sand. The force of gravity pulls the moon, earth and it's tides toward each other. The tides differences are mostly because of how much the moons gravity pulls on Earth. The Sun's gravity also pulls the Earth's water. The Sun, Moon, and Earth are nearly in line when there is a new moon on Earth. The gravity of the Sun and the Moon pull their gravity in the same direction, that form a tide with the greatest difference between a consecutive low and high tides called a Spring Tide. At a full moon, the moon and sun are on opposite sides of Earth. Since there are high tides on both sides of earth, a spring tide is also produced. It doesn't matter in which order the sun, earth, and moon line up. So we get spring tides twice a month during a full moon and new moon. When the moon first enters quarter phases, are line between earth and the sun is at right angles to the line between the earth and moon. The sun's pull is at right angles to the moon's pull which produces Neap tide. This is a tide with the least difference between consecutive low and high tides. The neap tide occurs twice a month, at first and third quarter moon.
Key Concept Questions
1. Q> What causes the Moon the shine?
A> The reflection of the Sun's light.
Q> Why does the moon appear to change shape throughout the course of the month?
A> Because we see the sunlight hit the moon at different angles. For example: when
the sun is behind us, the moon looks fuller because earth is blocking nearly all
light is being blocked which allows us to see all of the moon. When the sun is off
to the side we only see a part of the moon because some of the light is blocking
or casting a shadow on it.
2. Q> What is an eclipse?
A> An eclipse in when either the moon or earth is blocking the sunlight against the
Q> How is a solar eclipse different from a lunar eclipse?
A> A solar eclipse is when the moon blocks sunlight from the earth. A Lunar
eclipse is when the earth blocks sunlight from the moon.
Q> Why isn't there a solar eclipse and a lunar eclipse each month?
A> Because the moons orbit around the earth is tilted.
3. Q> What causes the tides?
A> Because of the earth's and the moon's gravity pulling on each other.
Q> Explain why most coastal regions have two high tides and two low tides each
A> Because when the moon and sun are orbiting the earth they both pass the
spot side twice a day, IE: morning and night.
When the Italian scientist, Galileo Galilei heard about a telescope in 1609, the telescope was a device to observe distant objects by making them appear larger. He decided make his own telescope by putting two lens in a wooden tube. The lens focused the light within the tube to make the far off object larger and brighter and with more detail than anyone before. Instead of seeing a perfect sphere, he saw craters and canyons. The moon surface has dark surfaces that Galileo called Maria; the Latin word seas. Galileo incorrectly thought that the Maria were oceans, however they are actually hardened rock formed from Lava flow from 3 to 4 billion years ago. Galileo saw that the moon's service was covered with craters. Some of them are many kilometers across. Scientist mistakenly thought they had been made by volcano's, but were caused by packs of meteoroids, chunks of rocks from space.
If you had to take a vacation to the moon, you would have to travel 384,000 kilometers (about 30 times the Earth's diameter). This makes the moon, the Earth's closest neighbor in the Milky Way. The moon is 3,476 kilometers in diameter, a little less than the distance of the United States. This is about one fourth of the earth's diameter however the moon has only one eighteenth the mass as earth. Even though Earth has a very dense core it's outer layers are less dense. The moon's average density is smaller than the density of earth's outer layers. On the moon's surface temperature ranges from a high of 130 degrees Celsius to a frigid -180 degrees Celsius. Temperatures vary on the moon's surface because it has no atmosphere and the gravity is so week that gases can easily escape into space. So, if you fart in space no one can smell it.
People have long wondered how the moon formed. Scientist have suggested many possible theories such as; Was the moon formed somewhere else and then captured by Earth's gravity as it came near? Or was the moon formed near earth while earth formed? My theory is: Was the moon formed when an asteroid hit the earth and molded by lava? But, scientist have many reasons to reject these ideas. The theory of the moon's origin that seems to best fit the evidence is called, the "Collision Ring" theory. The theory states that about 4.5 billion years ago when earth was very young in the solar system, the solar system was filled with many rocky debris. So of the debris was the size of small planets, so scientist theorized that the planet sized object collided with earth to form the moon. So, my theory was close to the collision theory.
Key Concept Questions
1. Q> Name three major features of the moon's surface?
A> They are: Maria's, Craters, Meteoroids, Canyons.
Q> How did the moon's craters form?
A> Meteors, Meteorites or Meteoroids hitting the moon's surface.
Q> Why is the moon's surface more heavy cratered than the earth's surface?
A> Because the moon gets hit by more meteors, meteorites and meteoroids. This is
also, much more hardened rock formed by lava.
2. Q> Describe the different ranges of temperatures on the moon's surface.
A> 130 degrees Celsius in direct sunlight and -180 degrees Celsius in the dark.
Q> Compare Earth's and the Moon's size and surface gravity.
A> The Moon is about 1/4 the Earth's diameter and the moon's gravity is about 1/8
the earth's gravity.
Q> What is the relationship between the moon's surface gravity, lack of an
atmosphere, and temperature range?
A> The temperatures vary on the surface because it has not atmosphere and the
gravity is so week, that the gases can easily escape into space.
3. Q> What was the solar system like when the moon formed?
A> No one truly knows.
Q> Explain the various stages in the formation of the moon.
A> No on truly knows.