Long ago, in a galaxy far, far

away…

Actually, the galaxy isn’t that far away. In fact, we live in it. It’s

called the Milky Way.• The Milky Way is a spiral galaxy.

• Our Solar System is located on one of the arms

A galaxy is a large group of stars, gas, and dust held together by gravity.

Galaxies also include:

• Planets

• Moons

• Asteroids

• Comets

There are three major types of galaxies

Spiral Elliptical Irregular

Now, onto Earth…• Earth spins on an axis, an imaginary line

going through the poles.• Earth spinning on it’s axis is called rotation.• Spinning a top is an example of rotation.• Our axis is tilted at a 23.5 degree angle.

Rotation• It takes about 24

hours, or one day for Earth to rotate once.

• Rotation is what causes night and day.

• When we face the sun, it is day, when we are facing away from the sun, it’s night.

Is it night or day in Utah?

Revolution• Revolution is when an object orbits another

object.

• An orbit is a path around another object.• The moon revolves around the Earth and the

Earth revolves around the sun.

What does it mean when someone says, “The world doesn’t revolve around you?”

Orbits

The moon orbits Earth. The Earth orbits the Sun.

All planets orbit the Sun. Even Haley’s Comet has an orbit.

What causes Seasons?• Answer: The tilt of the Earth’s axis.

• When the Northern Hemisphere is tilted toward the sun, it is summer.

• While the Northern Hemisphere is in summer, the Southern Hemisphere is in winter.

• When the Southern Hemisphere is in fall, what season is the Northern Hemisphere in?

Seasons

Solstices• The solstice is the

day when the Sun reaches its greatest distance north or south of the equator.

• The summer solstice is June 21 or 22.

• The winter solstice is December 21 or 22.

Equinoxes

• The equinox occurs when the Sun is directly above the Earth’s equator.

• The spring equinox is March 21 or 22.

• The fall equinox is September 22 or 23.

Quiz TimeCan you name the seasons?

What causes the seasons?

The Moon• The moon rotates in its axis and

revolves around Earth.

• We only see one side of the moon because it takes the same amount of time to revolve as it does to rotate.

• The moon appears to change shape as its position to the Earth and Sun changes.

Earth only sees the side of the moon with the arrow. It takes the moon 27.3 days to revolve around the Earth and 27.3 days to rotate on its axis once.

Phases of the Moon

• Waxing means the moon looks like it is getting larger.

• Waning means the moon looks like it is getting smaller.

• A full moon is when it looks like we see all the moon.

• We are really only seeing the half of the moon that is facing us.

Phases of the Moon• Like the Sun, the

moon rises from east to west.

• The moon does not produce its own light.

• It reflects light from the Sun.

• It takes 29.5 days for the moon to complete a cycle, but it takes 27.3 days for it to revolve around the Sun.

• The reason these numbers are different it because it takes the moon 2 extra days to catch up with the Earth’s revolution.

Tides

• Tides are caused by the gravitational pull of the moon.

• There are two high tide and two low tides daily.

• They occur every 12 hours.

What is an Eclipse?• An eclipse is where the Earth or the

moon temporarily block the sunlight from reaching each other.

• We don’t have eclipses all the time because the moon, Earth, and Sun have to be lines up exactly.

• The Earth’s orbit and the moon’s orbits are not on the same plane, so this doesn’t happen very often.

Lunar Eclipse

Lunar Eclipse

When the Earth’s shadow falls on the moon, a lunar eclipse occurs.

Lunar Eclipse over Prague.

Solar Eclipse

Partial Solar Eclipse

• A solar eclipse occurs when the moon moves directly between the Sun and Earth and casts its shadow over part of the Earth.

Total Solar Eclipse• During a total solar eclipse, the only part

of the Sun we see is a pearly, white glow around the shape of the moon.

Total Lunar Eclipse• Anyone can see a total lunar eclipse if

they are on the night-time side of the Earth where the moon is not hidden by clouds.

Our Solar System

• Our Solar System is made up of eight planets, meteorites, asteroids, and comets.

Comets• A comet is made of

ice and dust particles mixed with frozen water, methane, and ammonia.

• Haley’s comet is the most famous.

• It passes the Earth every 76 years.

Meteoroids• Comets tend to vaporize and break apart.• The small pieces are called meteoroids.

Meteor• When a meteoroid enters the Earth’s atmosphere and burns up, it’s called a

meteor.

• Sometimes we call meteor’s “shooting stars.”

Meteorite• Sometimes a meteoroid is too big and doesn’t

burn up in the Earth’s atmosphere.

• It hits the Earth and it called a meteorite.

• Meteorites form craters.

Asteroids

• An asteroid is a piece of rock similar to the material planets are made of.

• Most asteroids are located in the Asteroid Belt between Mars and Jupiter.

Planets

Planets in Order

• My• Very• Educated• Mother• Just • Served• Us • Nachos• ( & Pizza)

• Mercury• Venus• Earth• Mars• Jupiter• Saturn• Uranus• Neptune• (& Pluto & other Dwarf

Planets