The solar system and beyond

Students know the patterns of stars stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons.. Students know telescope

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Genre Comprehension Skill Text Features Science Content

Nonfi ction Predict • Captions

• Labels

• Glossary

Objects in Space

Scott Foresman Science 3.6

Standards Preview

Standard Set 4 Earth Sciences

4 Objects in the sky move in regular

and predictable patterns As a basis

for understanding this concept:

4.a Students know the patterns of

stars stay the same, although they

appear to move across the sky nightly,

and different stars can be seen in

different seasons.

4.c Students know telescopes magnify

the appearance of some distant objects in the sky, including the Moon and the planets The number of stars that can be seen through a telescope is dramatically greater than the number that can be seen by the unaided eye.

4.d Students know that Earth is one of

several planets that orbit the Sun and that the Moon orbits Earth.

ISBN 0-328-23534-2

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Earth Sciences

by Lillian Duggan

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asteroid

binoculars

orbit

planet

solar system

star

telescope

Picture Credits

Every effort has been made to secure permission and provide appropriate credit for photographic material The

publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.

Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-23534-2

This publication is protected by Copyright, and permission should be obtained from the publisher prior to any

prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,

mechanical, photocopying, recording, or likewise For information regarding permission(s), write to

Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.

1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06

by Lillian Duggan

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The Sun

A star is a huge ball of hot, glowing gases The Sun is

a star The width of the Sun is equal to the width of 100

Earths placed side by side The Sun is extremely hot The

surface of the Sun has a temperature of about 5,500ºC

Temperatures at the center of the Sun are much hotter

Temperatures on the

Sun’s surface reach 5,500ºC

The Sun’s center is much hotter than the surface.

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The Sun is closer to Earth than any other star This makes the Sun look larger and brighter than any other star Other stars look smaller than the Sun because they are much farther away

Earth and other objects move around the Sun in patterns The Sun causes these patterns The movement

of the Earth makes it hard to fi gure out these patterns It took many years for scientists to fi gure them out

The Sun looks large and bright in the sky

Other stars look much smaller

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Objects in the Solar System

A planet is a large body of matter that travels around

the Sun Planets and other objects that travel around the

Sun move in regular patterns that can be predicted The

path an object takes as it moves around the Sun is its

orbit Each planet’s orbit has a slightly oval shape

The Sun, the planets and their moons, and other

objects that orbit the Sun make up the solar system At

the center of the solar system is the Sun The strong pull

of the Sun’s gravity keeps the planets orbiting

Mercury

Venus

Earth

Mars Asteroid Belt

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Planets of the Solar System

The planets closest to the Sun are Mercury, Venus, Earth, and Mars The planets farthest from the Sun are Jupiter, Saturn, Uranus, and Neptune In 2006, scientists decided to call Pluto a “dwarf planet.” The closest planets orbit the Sun faster than the farthest planets

Between Mars and Jupiter are thousands of objects that are smaller than the planets These are asteroids An

asteroid is a large mass of rock Asteroids orbit the Sun.

Jupiter

Saturn

This diagram shows the solar system’s features The distances and sizes are not true to scale.

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The Motion of the Moon

The Moon makes one complete turn on its axis in

27 Earth days It orbits Earth once in about the same

amount of time

Because the Moon turns so slowly on its axis, the

same side of the Moon always faces Earth Whenever

you look at the Moon, you always see the same side of it

People saw the far side of the Moon for the fi rst time in

1959 when a spacecraft took pictures of it

In the time that the Moon takes

to orbit Earth, it also makes a

turn on its axis.

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The Moon is the closest object to Earth in space

Other than the Sun, the Moon is the brightest object

in the sky The Moon does not make its own light It appears lit because sunlight shines on it This light is refl ected to Earth

The picture below shows how Earth and the Moon appear from space Each night we see a different amount

of the lit part of the Moon

Several planets move across the fi xed pattern of stars

Like the Moon, these planets refl ect light from the Sun

The moonlight we see from Earth is refl ected sunlight.

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Studying Objects

In Space

A telescope is a tool for making distant objects

appear nearer and larger Many telescopes use pieces of

glass called lenses to bend light Telescopes with large,

curved mirrors can collect larger amounts of light The

light is directed to a lens to create a bright image

Binoculars are two telescopes joined together as a

unit The image you see through binoculars is sharp and

clear However, binoculars cannot magnify objects as

much as telescopes can

Using a telescope

or high-powered binoculars, you can see Saturn’s rings.

9

Studying the Planets

Mercury, Venus, Mars, Jupiter, and Saturn can all be seen without a telescope But you need binoculars and telescopes to see things on the planets’ surfaces For example, Mars has polar ice caps With a telescope, you can see them clearly against the planet’s red soil

The details of Uranus and Neptune are too far away

to be seen even with a telescope We have learned about the features of these planets from space probes These probes have taken pictures and made measurements

With a telescope you can see Jupiter’s clouds You can also see four of Jupiter’s moons

Neptune has rings At times, clouds appear on its surface.

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Looking at Stars and Galaxies

Suppose you’re outside on a clear, dark night You

look up to see thousands of tiny stars Through a

telescope you can see even more stars These stars are

different in size, color, and brightness Sometimes a

galaxy will look like a star A galaxy is a group of stars,

dust, and gas that are in the same area

If you view the Andromeda

galaxy without a telescope,

it looks like a small, blurry star.

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Comparing Stars

You might think at fi rst that the brightest stars are closer than the ones that are less bright But stars differ

in size and make different amounts of light Sometimes smaller stars make more light than bigger ones Stars that appear dim may be closer to Earth than stars that appear bright

The stars in this group have different colors and sizes.

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asteroid a large piece of rock that orbits the Sun

binoculars two telescopes joined together as a unit

orbit the path an object takes as it moves

around the Sun

planet a large body of matter that revolves

around a star such as the Sun

solar system a system made up of the Sun, the

planets and their moons, and other objects that orbit the Sun

star a huge ball of hot, glowing gases

telescope a tool for making distant objects appear

nearer and larger

1 Why does the Sun appear bigger and brighter than

other stars in the night sky?

2 What objects orbit the Sun between Mars and Jupiter?

3 How and when were people able to see the far side of

the Moon for the fi rst time?

describes how a telescope changes the appearance of objects Include simple supporting facts and details

farther from the Sun than Neptune be longer or shorter than the time it takes Neptune to orbit?

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