Name: __________________________________________ Date: ______________________ Period: ___________
Astronomy: Part 1: Earth in Space
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The tilt affects how much Sun each hemisphere gets.
Day and Night
Earth’s rotation causes day and night. Earth rotates on a tilted
_______________: an imaginary line running through the middle of it.
Earth _______________ on its axis once every _______________,
which is 1 day. At any given time, half of the Earth is in daylight, the
other in night.
Earth’s Orbit
Earth moves around the Sun. This is called a _______________.
Earth completes one revolution every year (_______________).
Earth’s path around the Sun is called its _______________. The
shape of the Earth’s orbit is a stretched oval, called an ___________.
Seasons
Earth’s tilted axis causes the _______________. Earth’s axis is tilted
at an angle of _______________. Earth’s axis always points in the
same direction as it moves around the Sun.
Summer: Northern Hemisphere points _______________ the Sunmost direct sunlight.
Winter: Northern Hemisphere points _______________from the Sunleast direct sunlight.
Spring: Northern and Southern Hemispheres receive
_______________ sunlight-days growing longer.
Fall: Northern and Southern Hemispheres receive _______________
sunlight-days growing shorter.
Name: __________________________________________ Date: ______________________ Period: ___________
Astronomy: Part 2: The Moon
The Moon
The Moon is Earth’s natural _______________. The Moon revolves
around the Earth every _______________. It rotates on its axis
_______________, too! This means that we always see the same
side of the Moon. We see the Moon because it reflects light from the
Sun.
Moon Phases
Each month, the Moon changes in appearance. The changes are
called ______________________________. The phase of the Moon
you see depends on how much of the sunlit dies of the Moon faces
us.
Eclipses
A _______________ is simply a shadow case in space. An eclipse
can occur in 2 ways:


When the Moon’s shadow hits Earth
When the Earth’s shadow hits the Moon
Solar Eclipses
A ____________________ occurs when the Moon comes in a direct
line between the Sun and Earth.
Lunar Eclipses
A ____________________ occurs when the Earth comes in a direct
line between the Sun and the Moon.
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Name: __________________________________________ Date: ______________________ Period: ___________
Tides
Neap Tides
The Moon also creates _______________ on Earth. Tides are the
_______________________________ of the ocean’s water every
12.5 hours or so. As the Earth rotates, the Moon’s _______________
pulls on water on the side of the Earth _______________ to it. The
Moon’s gravity pulls _______________ on the side furthest away.
Twice a month, the _______________ is true. The gravity of the
Moon is a ______________________________ to the Sun’s gravity,
producing a ____________________ tide. This is called a
______________________________.
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Astronomy: Part 3: The Solar System
Earth is the only one planet in our larger _______________________.
The solar system consists of the _______________, the
____________________________ and several kinds of
_____________________________. All objects in our solar system
revolve around the Sun along their own _______________.
The Sun
Spring Tides
Twice a month, the Moon, Earth and the Sun are all in a
_____________________________. The combined forces of gravity
of the Moon _______________ the Sun produce a
______________________________ tide. This is called a
______________________________.
Its mass makes up _______________ of all the mass in the Solar
System. Its gravity is strong enough to hold all the planets in orbit.
Produces energy by ______________________________.
Name: __________________________________________ Date: ______________________ Period: ___________
The Solar System
Venus
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Similar in size to Earth
Rotates the opposite way
90x surface pressure of Earth
Clouds of _______________ acid
Volcanoes and lava flows
Daytime temp: _______________
Earth
The Inner Planets
Mercury, Venus, Earth, and Mars are the
______________________________. These planets are small,
dense and have rocky surfaces. They are also called
_______________ planets.
Mercury

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
Smallest terrestrial planet
Closet planet to the Sun
Smaller than the Moon
No moons of its own
Daytime temp: _______________
Nighttime temp: _______________

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Liquid water on its surface
Atmosphere rich in _______________
One moon
Huge diversity of life
Distance from Sun: _______________
Home!
Mars
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The “red planet”
Very thin atmosphere of _______________
Tilted axis creates seasons
Ancient streams and lakes?
May house liquid water?
Two moons: Phobos & _______________
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Name: __________________________________________ Date: ______________________ Period: ___________
The Outer Planets
Jupiter, Saturn, Uranus and Neptune make up the
_____________________________. The first 4 are much larger than
Earth, do not have solid surfaces and are called
______________________________. Pluto is now classified as a
___________________________.
Jupiter
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Diameter - _______________ Earths
Mass - _______________ Earths
Surface of hydrogen & _______________
Likely has a solid rocky core
Great Red Spot: a giant storm (continuous hurricane)
Has _______________ known moons (as of 2006)
Saturn





Second largest planet
Least dense of all planets
Very hot inner core
Rings are made up of millions of _______________ & rock
particles
_______________ known mons (as of 2006)
Uranus

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Diameter – 4 Earths
Blue-green atmosphere
Very bright surface
Rotates top to bottom
One “year” = ______________ Earth years

Has 27 known moons (as of 2006)
Neptune
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
A cold, blue planet
Discovered first by mathematical prediction
Orbit crosses Pluto’s orbit
1 “year” = _______________ 165 Earth years
13 known moons (as of 2006)
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Name: __________________________________________ Date: ______________________ Period: ___________
Pluto: A Dwarf Planet

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
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Now a ___________________________
Smaller than our Moon
Its largest Moon, _______________ is more than half the size
of Pluto…it should be called a
_________________________________________________
Has 3 known moons (as of 2006)
Why is Pluto not a Planet?
In 2006, the International Astronomical Union (IAU) created 3 rules for
something to be called a planet:

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

The object must be orbiting the sun on its own. It cannot be
orbiting another body, like a moon.
It must be the shape of a sphere
It must have a clear “orbital neighborhood”. There must be no
other object in its path.
Pluto does not qualify because its moon, Charon is large and
they orbit ____________________.
Dwarf Planets
Pluto has been reclassified as a ____________________________.
The 4 characteristics of dwarf planets include:




They orbit the Sun
They are nearly spheres
They do not orbit any other planet
They do not have a clear “orbital neighborhood”
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Smaller Bodies
There are lots of ______________________________ in the solar
system. They can be classified as _______________,
_______________ and _______________.
Comets
Comets can be thought of as “dirty snowballs”. Comets are a
collection of ________________________________________ that
travel in a long orbit. The “ball” of a comet is called the
________________ and the tail region is called the
_______________.
Asteroids
Asteroids are objects too small to be planets. Most asteroids revolve
around the Sun in an _____________________________ between
Mars and Jupiter. Scientists think that s large asteroid hit Earth 65
million years ago, killing the dinosaurs.
Meteoroids
A meteoroid is a small chunk of dust or rock. _______________
break off comets and asteroids. When one enters the Earth’s
atmosphere, it creates a streak of light called a _______________. If
a meteor hits the Earth’s surface, the piece of rock is now called a
_______________.
Name: __________________________________________ Date: ______________________ Period: ___________
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Astronomy: Topic 4: Stars, Galaxies, and the Universe
Color and Temperature
Our Sun
The color of a star is determined by its temperature. As objects are
heated up, they turn from orange to red to yellow, all the way to white.
Our Sun is similar to all stars. Stars are huge spheres of glowing hot
gases. Stars are made up mostly _______________ (and some
Helium). They produce energy by nuclear fusion.
Size
There are huge differences in the size of stars. As large as our Sun
is, it’s only an average star.
Brightness and Distance
Classifying Stars
Stars can be very different. Astronomers classify stars in
______________ ways.
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

Color and Temperature
Size
Brightness and Distance
Some stars appear to be brighter than others. The brightness of a
star depends on both its _______________ and _______________.
There are 2 ways of describing brightness:
Apparent brightness
brightness as seen from Earth
Pros/Cons
Easy to measure
Not very accurate
Absolute brightness
brightness is all the same
distance
Pros/Cons
Very accurate
Must know distance
Name: __________________________________________ Date: ______________________ Period: ___________
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Light Years
Birth
The distances in space are enormous. Astronomers use a unit called
_____________________________ to measure distance between
stars. A light-year is the distance that light travels in one year.
All stars are formed inside a giant cloud of gas and dust called a
_______________. In some parts of the nebula, gas and dust are
pulled together to form a ______________________________.
Eventually, the sphere becomes larger. The center grows hot enough
for _______________ to occur.
Light travels _______________ km in 1 s. One light year =
______________________________!
Our closest star, _____________________________, is 4.3 light
years from the Sun.
Life Cycle of Stars
Stars have life cycles just like humans. Each star is born, goes
through its cycle, and dies.
Main Sequence
The star produces energy by nuclear fusion during the main sequence
stage. How long stars stay in the main sequence depends on how
large they were to start:


______________________________ burn fuel slowly and
stay in the main sequence for
______________________________.
______________________________ burn their fuel quickly
and stay in the main sequence for _______________ of
years.
Dying
When a stay begins to _____________________________ fuel, it
expands tremendously. _____________________________ expand
to turn into _____________________________. Higher_____________________________ become red _______________.
Death
Once a star runs out of fuel, it becomes a
_______________________________, a
______________________________ or a
______________________________.
Name: __________________________________________ Date: ______________________ Period: ___________
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
Lower-mass stars shed their outer layer, creating a new
________________. What’s left behind is a tiny hot core
called a ______________________________.
_______________________________ (formed by highermass stars) can suddenly explode in a _______________.
The remaining materials form a
____________________________.
The ________________________________________ leave
a large amount of mass behind after they explode. The
gravity of the mass is so strong, it pulls everything around it,
forming a ____________________________.
Galaxies
Most stars are found in galaxies. A _______________ is a huge
group of stars, solar systems, dust and gas held together by
gravity. Galaxies are classified into 3 major types:
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Name: __________________________________________ Date: ______________________ Period: ___________
Spiral Galaxies

Have a bulge of older stars in the middle with arms of
younger stars the spiral outward.
The Milky Way
Our solar system is found in the
______________________________. The Milky Way is a spiral
galaxy shaped like a pin wheel with a huge bulge in the center. The
Milky Way is enormous: it is over 100,000 light years in diameter!
Elliptical Galaxies

Shaped like spheres or flattened eggs. All of the stars
present are old.
Irregular Galaxies

Faint galaxies with no regular shape. Smaller than most
galaxies with fewer stars.
The Universe
The universe is unbelievably huge. The universe is defined as all of
space and everything inside it. Astronomers theorize that billions of
years ago, the universe formed in a huge, cosmic explosion. The
events are described by the ______________________________.
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Name: __________________________________________ Date: ______________________ Period: ___________
Big Bang Theory
Big Bang Theory states that around
______________________________, all of the material was
compressed into an extremely hot and massive point called a
singularity. In an instant, the singularity exploded, sending matter,
space and time in all directions.
The early universe was hot. It was
___________________________________ C hot! Because of the
tremendous heat, none of the matter could combine together to form
new things. Soon, the expanding universe cooled down. After a few
thousand years, the first sub-atomic particles, atoms and elements
formed.
The early universe continued to _______________. As it continued to
cool down, the first stars and galaxies came together. The universe
continues to expand even to this day.
Evidence for the Big Bang
Big Bang Theory has been confirmed by 2 types of evidence.
1. Moving Galaxies
a. In the 1920’s, an astronomer named
______________________________ discovered that
galaxies are moving away from each other.
b. He also created _____________________________:
the farther away a galaxy is from us, the faster it is
moving away.
2. Cosmic Background Radiation
a. In 1965, two American physicists accidentally
detected faint ______________________________.
b. Astronomers later found that the faint radiation was
coming from ____________________________ in
space.
c. The radiation may be left from the bag bang.
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