Table Of ContentT
H
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V
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U
A
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G Understanding
U
I Universe
D The
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ISBN 2-7644-0017-9
9 782764 400173 QA INTERNATIONAL
Understanding
Universe
the
Publisher Jacques Fortin
Editorial Director François Fortin
Executive Editor Serge D’Amico
Art Director Marc Lalumière
Graphic Designer Anne Tremblay
Writers Nathalie Fredette
Claude Lafleur
Computer Graphic Artists Mamadou Togola
Alain Lemire
Hoang-Khanh Le
Ara Yazedjian
Mélanie Boivin
Jean-Yves Ahern
Michel Rouleau
Page Layout Lucie Mc Brearty
Véronique Boisvert
Geneviève Théroux Béliveau
Researchers Anne-Marie Villeneuve
Anne-Marie Brault
Astronomy Reviewer Louie Bernstein
Copy Editor Jane Broderick
Production Gaétan Forcillo
Guylaine Houle
Prepress Kien Tang
Karine Lévesque
Translation Käthe Roth
Canadian Cataloguing in Publication Data
Main entry under title:
The visual guide to Understanding the Universe
(The visual guides to knowledge)
Translation of: Comprendre l’Univers
Includes index
ISBN 2-7644-0891-9
1. Astronomy- Encyclopedias. 2. Cosmography - Encyclopedias. 3. Planets -
Encyclopedias. 4. Stars - Encyclopedias. 5. Outer space - Exploration -
Encyclopedias. 6. Astronomy - Observations - Encyclopedias. I. Series.
QB14.S4213 2007 520’.3 C99-941237-X
The Visual Guide to Understanding the Universewas created and produced by
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No part of this book may be reproduced or transmitted in any form or by any means,
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We acknowledge the financial support of the Government of Canada
through the Book Publishing Industry Development Program (BPIDP)
for our publishing activities.
Printed and bound in Canada.
10 9 8 7 6 5 4 3 2 1 04 03 02 01
www.qa-international.com
Understanding
Universe
the
QA INTERNATIONAL
Ta b l e o f
46 Dwarf planets
45 Neptune
44 Uranus
43 Saturn
42 Jupiter
40 Comets
38 Meteorites
37 The asteroids
36 Mars
35 Lunar eclipses
34 Lunar phases
32 The Moon
30 The seasons
29 Astronomical coordinates
28 Geographic coordinates
26 Earth’s atmosphere 74 Active galaxies
24 The magnetosphere 73 Galactic clusters
22 The origin of Earth 72 The Local Group
21 Earth 70 The Milky Way
20 Venus 69 Classification of the galaxies
19 Mercury 68 The galaxies
6 | The solar system 17 | Planets and Satellites 47 | The Stars 66 | The Galaxies
8 The solar system 49 The origin of stars
10 Comparative table of the planets 50 Multiple stars
12 The Sun 51 Classification of stars
14 How the Sun evolved 52 Low-mass stars
16 Solar eclipses 54 Massive stars
56 Black holes
58 Star clusters
60 The constellations
62 The constellations of the Southern Hemisphere
64 The constellations of the Northern Hemisphere
4
c o n t e n t s
119 Exploring small astral bodies
118 Ulysses
117 Cassini and Huygens
116 Galileo
115 Voyager
114 Pioneer 10 and 11
113 Magellan
83 Cosmic background radiation
110 Exploration of Mars
82 The Universe expands
108 Exploration of the Moon
80 The Big Bang
106 Space probes
78 The size of the Universe
104 Surrounding Earth
76 | Structure of the Universe 84 | Astronomical 102 | Space 120 | Glossary
observation Exploration
122 | Index
86 The electromagnetic spectrum
88 Telescopes
90 Astronomical observatories
92 A new generation of telescopes
94 The Hubble Space Telescope
96 Radio telescopes
98 Life elsewhere in the Universe
100 Extrasolar planets
5
infinitely small
incredibly big
Although it seems from our point of view, the solar system is
on the scale of the universe
. Nevertheless, studying it is invaluable for acquiring
knowledge of the cosmos as a whole. After all, our Sun, the fiery ball around which the planets orbit, is a star just
like any of the “astronomical”number of stars in the universe!
The solar system
8 The solar system
Our little corner of the universe
10 Comparative table of the planets
Tour of the solar system
12 The Sun
A very ordinary star
14 How the Sun evolved
Our Sun: its birth and its fate
16 Solar eclipses
A spectacular disappearing act
T h e s o l a r s y s t e m
Nine planets circling the Sun
m The solar system includes one star (the Sun), nine planets, about 60 natural
e
st satellites orbiting the planets, thousands of asteroids (small rocky objects),
y
s
millions of comets (lumps of dust and frozen gas), billions of meteoroids, and
r
a
ol interplanetary dust and gas.
s
e
h
T THE MILKY WAY
Our solar system is on the edge of the Milky Way, our galaxy. The Milky Way stretches over some 12 billion
billion (or 12 million million million) km. If we think of the Milky Way as a beach, our solar system is just a
grain of sand.
THE OUTER PLANETS
The giant planets farthest away from the Sun are gaseous globes (made mainly of hydrogen and helium),
which all have rings and a number of satellites.
Sun Jupiter Saturn
Uranus
Plutois the most distant planet from the
Sun. It is also the smallest and coldest planet The Kuiper Belt, located beyond Neptune
in the solar system, and is in a class by itself. Neptune’s orbit, is formed of objects
made of ice; it is similar to Pluto in
composition.
THE ECLIPTIC
All planets revolve around the Sun on approximately the same plane of orbit,
Pluto(17.2˚)
the ecliptic, which is defined as the plane of Earth’s orbit. The chart
below shows the inclination of the planets’ orbits; Pluto’s
orbit inclines the most sharply.
solar
equator
Earth(0˚) Jupiter(1.3˚) Mars(1.9˚) Venus(3.4˚)
Uranus(0.8˚) Neptune(1.8˚) Saturn(2.5˚) Mercury(7˚)
8
E0
CELESTIAL OBJECTS
In general, a star (such as the Sun) is a heavenly body
that emits a great quantity of energy (light and heat).
A planet Qis a body that orbits a star and reflects
part of that energy; a natural satellite W(or moon) m
revolves around a planet. All nine planets orbit e
t
around the Sun in a counter-clockwise direction E. Sun ys
s
Except for Venus and Uranus, they also rotate
r
a
counter-clockwise on their axis R. ol
s
Planets travel around the Sun in an elliptical
e
orbit – in other words, their path is slightly h
W0 T
oval. Only Mercury and Pluto have orbits that
are visibly oval.
Q0
R0
elliptical orbit
In spite of the many objects of all sorts in the solar
system, it is almost empty. Most illustrations show
the planets close together, but there are in fact vast
empty spaces between them. The distances between
the outer planets are even greater.
The Oort Cloud, made up of trillions of comets,
orbits the solar system at a distance of about
4,500 billion kilometers.
THE INNER PLANETS
The planets closest to the Sun are smaller and
very dense; they are telluric, or rocky.
Mercury
Earth
Mars
The asteroid belt, which forms the border between
the inner and outer planets, is the region of the Venus
solar system where the most asteroids are found.
9
