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This is a picture I took of the moon.

# Chapter 1: Earth, Moon, and Sun

Photo Of Sun, Earth, Moon and Space.

# Section 1-Earth in Space

## 1. How does Earth Move in Space?

Earth moves through space in two major ways-Rotation and Revolution.

The Earth spins on an Axis which is called Rotation.                                                 Earth's axis passes through the North and the South Poles.  Earth's Rotation causes day and night.  When you look outside in the morning, you see the sun rising in the East. When you look at night, you see the sun falling in the West. This is because the Sun rotates Eastward.  When you are facing away from the sun it is night time, and when you are facing towards the sun it is daytime.

When the Earth is rotating, the Earth is moving around the Sun which is called   Revolution. Revolution is the movement of one object around another.  When you complete one revolution around the sun it is called a year.  Earth's orbit isn't circular.  It is called an ellipse.  It takes 365.25 days to complete one revolution around Earth. People use calendars to keep track of time on Earth.  A calendar is a system of organizing time that sorts out the beginning, length, and divisions of a year.  The reason behind adding 1/4 of a day to the year was because Earth travels in an oval shape, not a circle.

This images shows the different Regions.

## 2. What causes the cycle of seasons on Earth?

Earth has seasons because its axis is tilted as it revolves around the sun.

Earth's axis is tilted at 23.5° from the vertical.  As it revolves around the sun, the north and the sound ends of the axis are either away or toward the sun.  Summer and winter are caused by Earth's tilt as it revolves around the sun. Soltices are when the sun is the farthest north or south of the equator.  An Equinox is when neither hemispheres is tilted toward or away from the sun.  During an equinox, day and night are about 12 hours everywhere on Earth.  June Solstice is on June 21. This is when the the Northern end of Earth's axis is tilted towards the Sun.  It is Summer in the Northern Hemisphere and Winter in the Southern Hemisphere.  During March and September Equinoxes, neither end of Earth's axis is tilted toward the sun, so both hemispheres receive the same amount of energy.  During December Solstice, the Northern hemisphere is tilted away from the Sun.  It is summer in the Southern Hemisphere and winter in the Northern Hemisphere.

This Image shows what seasons are in the Souterhn Hemisphere.

## What determines the strength of the force of gravity between two objects?

Isaac Newton formed a hypothesis that the force that pulls an apple to the ground also pulls the moon toward Earth, keeping it in orbit which is called gravity.  Gravity attracts all objects toward each other.  Newton's law of universal gravitation states that every object in the universe attracts every other object.

## What two factors combine to keep the moon and Earth in Orbit?

There are two factors that objects depend on: the masses of the objects and the distance between them. The law of gravitation states that all objects around you are pulling on you. The reason why we can't feel them pulling on us is because the strength of gravity depends in part on the masses of each object. The amount of matter in an object is called mass. Earth applies a gravitational force on Earth. The force of gravity on an object is known as its weight.  An object's weight can change depending on its location, unlike its mass.  For example if you stood on the moon, you would way 1/6 of your weight now because the moon is much less massive than Earth, so the gravity pulling on you would be much less. The strength of gravity is affected by the distance between two objects as well as their masses.  The force of gravity decreases rapidly as distance increases.  For example, if the distance between two objects were doubled, the force of gravity between them would decrease to one fourth of its original value.

INERTIA AND ORBITAL MOTION

The tendence of an object to resist a change in motion is Inertia.  If you are riding in a car and it stops, you keep moving forward. You feel the effects of Inertia every day. An object with greater inertia is more difficult to stop or start.  Newton's first law of motion is that an object at rest will stay at rest and an object in motion will stay in motion ith a costant speed and direction unless acted on by force.  The moon and Earth remain in their orbits because inertia and gravity combine to keep Earth in orbit around the sun and the moon in orbit around the Earth.

## 1. What causes the phases of the Moon?

The changing relative positions of the moon, Earth, and sun cause the phases of the moon, eclipses, and tides.

The moon rotates once on its axis in the smae amount of time Earth rotates in a day.  A day and a year is the same length of time as it is on Earth.  For this reason, the same side of the moon is always facing the Earth.

Phases of the Moon

If you look at the moon, and it appears round or in phases, this is because it reflects light from the sun.  Phases are caused by changes in the relative positions of the moon, Earth and the sun.  Since the moon revolves around Earth, you see the moon from different angles. The phases of the moon we see depends on how much of the sunlit side of the moon faces Earth.

## What are Solar and Lunar Eclipses?

When the moon's shadow hits Earth or Earth's shadow hits the moon, an eclipse occurs.  When an object in space comes between the sun and a third object, it casts a shadow on that object causing an eclipse to take place.  There are two kinds of eclipses: Solar and Lunar eclipses. Solar means sun and Lunar means moon.

When do solar eclipses occur?

A solar eclipse occurs when the new moon passes directly between Earth and the sun, blocking sunlight from Earth. The very darkest part of the moon's shadow is the umbra, is cone-shaped.  Only people within the umbra experience a total solar eclipse.  During this period,the sky goes dark as night, the air gets cook and the sky becomes a scary color.

When do lunar eclipses occur?

During most months, the moon moves near Earth's shadow but not quite into it.  A lunar eclipse occurs at a full moon when Earth is directly between the moon and the sun.  They only occur only when there is a full moon because the moon is closest to Earth's shadow at that time. During a lunar eclipse, Earth blocks sunlight from reaching the moon. Like the moon's shadow in a solar eclipse, Earth's shadow has an umbra and a penumbra.  Unlike a total solar eclipse, a total lunar eclipse can be seen anywhere on Earth that the moon is visible. A partial lunar eclipse can occur when the moon passes partly into the umbra of Earth's shadow.  A lunar eclipse occurs for about two or three hours.

# COME WATCH THE SOLAR ECLIPSE WITH ME.WE WILL HAVE A BLAST BRING GUESTS.

6 people are going
Invite Friends
6 going1 maybe0 no

ITLL BE FUN

? CMusser 2 years ago

Eh

## What causes the tides?

Tides are caused mainly by differences in how much the moon's gravity pulls on different parts of Earth.  Tides occur every 12.5 hours. The water rises for about six hours and falls for six hours. The force of gravity pulls the moon and the Earth which includes the water toward Each other.  There are two tides, spring tide and neap tides.  A spring tide is a tide with the greatest difference between the low and high tides.  A neap tide is the tide with the least difference between the consecutive low and high tides.

## What features are found on the moon's surface?

The moon's surface consists of highlands, maria, ad craters.  Highlands are some of the light colored features on the moon.  Maria is a flat, dark area on the moon's surface formed from huge ancient lava.  Craters are large round pits that are caused by the impact of meteoroids.

## What are some characteristics of the moon?

The largest and most visible differences in comparison to Earth is that the moon is dry and has no atmosphere.  Its density is 3,476 km in diameter which is about a fourth of Earth's diameter.  The mass of the moon is 1/80 of Earth's mass.  The moon's temperature is 266 degrees Fahrenheit in direct sunlight and frigid of -292 degrees Fahrenheit.

## How did the moon form?

The most popular theory of how the moon formed is that a planet-sized object colidded with Earth to break of a section to form the moon.

### Comment Stream

2 years ago
0

nice job. i liked your video

2 years ago
0

I like the font that you used. It looks cool.

2 years ago
0

good job on the tackk and also good explanations on when lunar eclipse occurs.

2 years ago
0

Good Job!