Download Earth, Moon, Sun, and Stars

Earth, Moon,
Sun, and Stars
A Science A–Z Earth Series
Word Count: 755
Earth,
Moon,
Sun,
and Stars
Written by Alyse Sweeney
Visit www.sciencea-z.com
www.sciencea-z.com
Earth, Moon,
Sun, and Stars
Key elements Used in This Book
The Big Idea: Earth is part of a system of fast-moving objects in space.
Earth rotates on its axis, Earth revolves around the Sun, and the Moon
revolves around Earth. These movements affect important aspects of
our daily lives, including night and day, our calendars, the availability
of light and heat, and the appearance of the Moon and the Sun in
the sky. Humans have an ever-growing understanding of how the
Earth, Moon, and Sun move and interact. This understanding helps
us make sense of what we see in the sky, both by day and by night.
An understanding of our nearby space neighborhood can also inspire
future exploration deeper into space, which may someday even include
the discovery of life on distant planets.
Key words: air, atmosphere, calendar, circle, crescent, dark, day, Earth,
energy, full moon, gas, heat, light, month, Moon, neighbor, new moon,
night, orbit, phases, planet, reflect, revolve, rock, rotate, sky, space, spin,
star, Sun, water, year
Key comprehension skill: Cause and effect
Other suitable comprehension skills: Compare and contrast; classify information;
main idea and details; identify facts; elements of a genre; interpret graphs,
charts, and diagrams
Key reading strategy: Visualize
Other suitable reading strategies: Ask and answer questions; summarize;
connect to prior knowledge; using a table of contents and headings; using
a glossary and bold terms
Photo Credits:
Front cover: © Paul Paladin/Dreamstime.com; back cover, pages 7 (bottom), 11 (Earth):
© iStockphoto.com/Andrey Prokhorov; title page: © iStockphoto.com/David de Groot; page 4:
© Sean White/Design Pics/Corbis; page 5: © iStockphoto.com/Fanelli Photography; page 6:
© iStockphoto.com/Ewa Wysocka-Galka; page 7 (top): © iStockphoto.com/Eric Hood; pages 9 (Sun),
11 (Sun), 13 (Earth, Sun): © iStockphoto.com/George Argyropoulos; pages 9 (Earth, stars), 14 (Earth),
16 (Earth, stars), 11 (stars), 13 (stars): courtesy of NASA/GSFC; page 9 (car): © Jupiterimages
Corporation; page 11 (inset): © iStockphoto.com/Jill Chen; page 12: © Cathy Yeulet/123RF;
pages 14 (Moon), 16 (Moon): © iStockphoto.com/Dra Schwartz; page 15 (top): © Paul Paladin/
123RF; page 15 (bottom left): © iStockphoto.com/Andrey Stenkin; page 15 (bottom right):
© iStockphoto.com/Kativ; page 17: © iStockphoto.com/Manley620
Illustration Credit:
page 8: Cende Hill/© Learning A–Z
Written by Alyse Sweeney
www.sciencea-z.com
Earth, Moon, Sun, and Stars
© Learning A–Z
Written by Alyse Sweeney
All rights reserved.
www.sciencea-z.com
Table of Contents
Introduction
Introduction............................. p. 4
Earth...................................... p. 6
The Sun.................................. p. 8
When we look up into the sky, we
are looking into outer space. We can
see the Sun, the Moon, and stars.
They all seem to move very slowly
Day and Night....................... p. 11
across the sky.
A Year.................................. p. 13
We live on a giant ball of rock and
Our Moon............................. p. 14
it because we live on it! It is also
water called Earth. We don’t see
moving through space. It moves
Changing Shapes
of the Moon.......................... p. 16
in a giant circle around the Sun.
Conclusion............................ p. 17
Glossary............................... p. 18
If you stare at the
sky for an hour,
you might see the
stars move slowly.
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4
Mercury
Jupiter
Saturn
Uranus
Neptune
Venus
Earth
Mars
From the Sun, the planets are: Mercury, Venus, Earth,
Mars, Jupiter, Saturn, Uranus, and Neptune.
Earth
Earth is where we live. It is one of
From Earth, the Moon and the Sun are the biggest
objects we can see in the sky.
eight planets that go around the Sun.
The Moon is also a ball of rock but
smaller than Earth. The Moon moves
in a giant circle around Earth. As
Earth is the third planet from the Sun.
Being this far away keeps Earth from
getting too hot or too cold. Planets
Earth moves around the Sun, the
closer to the Sun are so hot that steel
Moon moves around Earth.
would melt. Planets farther away
Let’s learn more about Earth, the Sun
are way too cold. Earth has the
and stars, and the Moon. Let’s learn
right amount of heat and light for
about how they move through space.
plants and animals to live here.
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6
Most of Earth is
covered by water.
Light turns to heat.
Water is also
below ground and
in the air. That’s
The Sun
sends light
to Earth.
why Earth is called
the water planet.
Living things need water to live. They
also need air. Earth has a blanket
The Sun
The Sun is just one of billions of stars
in space. Like most stars, it is a giant
of air around it. This blanket of air
ball of very, very hot gas.
is called the atmosphere.
The Sun sends light to Earth. Light
from the Sun hits Earth. It lets us see
during the day. The light changes
The
atmosphere
is made of
water, oxygen,
and other
gases. It helps
keep in heat.
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to heat when it hits Earth. The heat
rises and warms Earth’s atmosphere.
Without the Sun, Earth would be
dark, cold, and lifeless.
8
The
Sun
Sirius
Pollux
Arcturus
Our Sun is small
compared to the
next-closest stars:
Sirius, Pollux,
and Arcturus.
109 Earths
Most stars are much bigger than our
Sun. The Sun looks bigger than other
stars because it is much closer to
Earth. But even though it is our closest
star, it is still very, very far away.
The Sun is so big that 109 Earths would fit across it.
If you could drive to the Sun at the speed
of a car on the highway, it would take
about 177 years to get there!
The Sun is much, much bigger than
Earth. If Earth were the size of a
marble, the Sun would be as big
as a ball over five feet tall. The
Sun is so big that one million Earths
146 million kilometers
(93 million miles)
would fit inside it!
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10
Day and Night
Earth is always spinning like a top,
or rotating. This rotating causes day
and night. When the side of Earth
we are on faces the Sun, we see the
Sun’s light. It is day. As we stand on
a spinning Earth, the Sun looks as if
it is moving across the sky.
Night comes when the side of Earth
we are on rotates away from the
Sun. The side facing away from
the Sun is dark at night. When it is
daytime on our side of Earth, it is
Night
nighttime on the other side of Earth.
Day
It takes 24 hours for Earth to rotate
once. That’s one day.
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12
A Year
The Earth also moves, or revolves,
around the Sun in a path called
an orbit. It takes 365 ¼ days for
Earth to make a complete trip
Four Moons would
fit across Earth. Fifty
Moons would fit
inside Earth’s ball.
around the Sun. That’s one year!
Our Moon
The Moon is Earth’s closest neighbor
in space. It is much smaller than
Earth. About 50 Moons would fit
inside Earth, or four Moons across it.
The Moon is much closer to Earth
than the Sun. If you could drive a
car to the Moon at the same speed
as driving down a highway, it would
Earth takes 365 ¼ days, or a year, to circle the Sun.
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take 150 days to get there.
14
Changing Shapes of the Moon
The Moon revolves around Earth
just as Earth revolves around the
Sun. It takes 28 days for the Moon
to travel once around Earth.
The Moon does not make its own
The Moon seems to change shape
light. The Moon shines because it
as it moves. It really does not
reflects the Sun’s light. We see the
Moon at night and sometimes during
the day. Moonlight is really sunlight
bouncing off the Moon.
change shape. We just see different
amounts of the sunlit side as the
Moon goes around Earth.
The Moon
takes 28
days to
orbit Earth.
Moon
Earth
New
Moon
15
16
Crescent
Moon
1st
Quarter
Full
Moon
3rd
Quarter
Conclusion
Glossary
Think about a calendar. A month is
a little longer than the time it takes
atmospherethe blanket of air surrounding
a planet, star, or moon (p. 7)
Earth
the Moon to go around Earth. A
the planet we live on (p. 4)
MoonEarth’s only natural satellite
(p. 5)
year is made of 12 months. In the
time it takes Earth to go all the way
around the Sun, the Moon goes
around Earth 13 times. A year
orbitthe path taken by one object
in space circling around
another larger object (p. 13)
planetsvery large objects that travel
in orbit around a star (p. 6)
usually has
365 days.
reflectsbounces off something like
a ball bouncing off a wall
(p. 15)
In the time
Earth makes
one trip
revolvesmoves in a circle around
something (p. 13)
around the
rotatingspinning around (p. 11)
Sun, Earth
starslarge, faraway objects
in space that make their
own light (p. 8)
spins 365
times. Are
Sunthe star that Earth goes
around (p. 8)
you dizzy yet?
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