The god of sky and earth.., p.1
Space, page 1
A Note from Mary Pope Osborne About the
When I write Magic Tree House® adventures, I love including facts about the times and places Jack and Annie visit. But when readers finish these adventures, I want them to learn even more. So that’s why my husband, Will, and my sister, Natalie Pope Boyce, and I write a series of nonfiction books that are companions to the fiction titles in the Magic Tree House® series. We call these books Fact Trackers because we love to track the facts! Whether we’re researching dinosaurs, pyramids, Pilgrims, sea monsters, or cobras, we’re always amazed at how wondrous and surprising the real world is. We want you to experience the same wonder we do—so get out your pencils and notebooks and hit the trail with us. You can be a Magic Tree House® Fact Tracker, too!
Here’s what kids, parents, and teachers have to say about the Magic Tree House® Fact Trackers:
“They are so good. I can’t wait for the next one. All I can say for now is prepare to be amazed!” —Alexander N.
“I have read every Magic Tree House book there is. The [Fact Trackers] are a thrilling way to get more information about the special events in the story.” —John R.
“These are fascinating nonfiction books that enhance the magical time-traveling adventures of Jack and Annie. I love these books, especially American Revolution. I was learning so much, and I didn’t even know it!” —Tori Beth S.
“[They] are an excellent ‘behind-the-scenes’ look at what the [Magic Tree House fiction] has started in your imagination! You can’t buy one without the other; they are such a complement to one another.” —Erika N., mom
“Magic Tree House [Fact Trackers] took my children on a journey from Frog Creek, Pennsylvania, to so many significant historical events! The detailed manuals are a remarkable addition to the classic fiction Magic Tree House books we adore!” —Jenny S., mom
“[They] are very useful tools in my classroom, as they allow for students to be part of the planning process. Together, we find facts in the [Fact Trackers] to extend the learning introduced in the fictional companions. Researching and planning classroom activities, such as our class Olympics based on facts found in Ancient Greece and the Olympics, help create a genuine love for learning!” —Paula H., teacher
Text copyright © 2002 by Will Osborne and Mary Pope Osborne
Illustrations copyright © 2002 by Sal Murdocca
Cover photograph copyright © Space Telescope Science Institute/NASA/ Science Photo Library
All rights reserved. Published in the United States by Random House Children’s Books, a division of Random House, Inc., New York. Originally published by Random House Children’s Books, New York, in 2002.
Random House and the colophon are registered trademarks and A Stepping Stone Book and the colophon are trademarks of Random House, Inc. Magic Tree House is a registered trademark of Mary Pope Osborne; used under license.
The Magic Tree House Fact Tracker series was formerly known as the Magic Tree House Research Guide series.
Visit us on the Web!
MagicTreeHouse.com
randomhouse.com/kids
Educators and librarians, for a variety of teaching tools, visit us at randomhouse.com/teachers
Library of Congress Cataloging-in-Publication Data
Osborne, Will.
Space : a nonfiction companion to Magic tree house #8, Midnight on the moon/by Will Osborne and Mary Pope Osborne ; illustrated by Sal Murdocca.
p. cm. — (Magic tree house fact tracker)
“A Stepping Stone book.”
Includes index.
eISBN: 978-0-307-97518-8
1. Astronomy—Juvenile literature. 2. Space flight—Juvenile literature.
I. Osborne, Mary Pope. II. Murdocca, Sal, ill. III. Title.
QB46.O762 2011 520—dc22 2011000306
Random House Children’s Books supports the First Amendment and celebrates the right to read.
v3.1
For Wil and Melanie Aiken
Scientific Consultants:
STEPHANIE L. PARELLO, Astronomy Education Coordinator, Hayden Planetarium, New York City
HEIDI JOHNSON, Earth Science and Paleontology, Lowell Junior High School, Bisbee, Arizona
RICHARD McCOLMAN, Morehead Planetarium and Science Center, Chapel Hill, North Carolina
Education Consultant:
MELINDA MURPHY, Media Specialist, Reed Elementary School, Cypress Fairbanks Independent School District, Houston, Texas
Very special thanks to Dr. Alan J. Friedman, Ph.D., Director, New York Hall of Science, for his professional hospitality, meticulous marble mathematics, stunning photographic contribution, and unflagging moral support.
We would also like to thank Paul Coughlin for his ongoing photographic contribution to the series and, again, our wonderful, creative team at Random House: Joanne Yates, Helena Winston, Diane Landolf, Cathy Goldsmith, Mallory Loehr, and, of course, our wonderful editor, Shana Corey.
Cover
Title Page
Copyright
Dedication
1. Astronomy
2. The Universe
3. The Sun
4. Our Solar System
5. Space Travel
6. From Earth to the Moon
7. Space Travel Today
8. Living and Working in Space
9. The Future
Doing More Research
Index
About the Author
People have always been interested in space.
Cave people painted pictures of the night sky on the walls of their caves. Ancient Egyptians believed there were Sun gods and Moon goddesses. The ancient Chinese built stone towers so they could study the sky more closely.
Over the centuries, people began to write down what they learned from looking at the skies. They gave the planets names. They made maps of the stars. They noted changes in the sky from month to month and from year to year.
The study of the skies became the very first science. This science is called astronomy (uh-STRAHN-uh-mee).
The word astronomy comes from the Greek language. It means “naming the stars.”
Ancient Astronomy
Nearly 2,000 years ago, an astronomer in Egypt named Ptolemy (TAHL-uh-mee) wrote the first books about astronomy. In his books, Ptolemy described how he thought the stars and planets moved in the sky.
Ptolemy believed that Earth was at the center of everything. He thought the Sun, stars, and everything else in the sky traveled around Earth.
For over a thousand years, nearly everyone accepted Ptolemy’s ideas as facts. They did not know that Ptolemy’s “facts” were completely wrong.
Copernicus
Nicolaus Copernicus (nihk-uh-LAY-us koh-PUR-nuh-kus) was a Polish astronomer. He lived nearly 1,400 years after Ptolemy. Copernicus studied Ptolemy’s ideas for a long time. He knew something was not right.
Copernicus figured out that the Sun does not travel around Earth. It’s really the other way around! Earth and all the other planets travel around the Sun.
Copernicus was afraid people would not accept his ideas. So he waited until he was about to die to let the world know what he thought. In 1543, he published a book that said Ptolemy was wrong.
Oh, wow! Copernicus died just a few months after his book was published.
Copernicus’s fears came true. People were furious when they read his book! They liked thinking that Earth was the center of everything.
For many years, it was against the law even to talk about Copernicus’s ideas. The few people who believed Copernicus kept their belief secret.
Galileo
One person who believed Copernicus was an Italian astronomer named Galileo Galilei (gal-uh-LAY-oh gal-uh-LAY). Galileo was sure Copernicus was right. But he didn’t know how to prove it.
One day, Galileo heard about a new invention. The invention was what we now call a telescope. The telescope made distant things seem closer.
The first telescopes were used mostly on battlefields.
Galileo couldn’t believe that no one had used a telescope to study the sky! He was so excited by this idea that he built a telescope of his own.
When Galileo peered through his telescope into the night sky, modern astronomy was born.
Galileo saw rings around the planet Saturn.
He saw moons circling the planet Jupiter.
He saw that the planet Venus seemed to change shape, just like our Moon.
And he saw that there were millions and millions of stars—far more than anyone had ever imagined.
The longer Galileo looked into the heavens, the more certain he became that Earth was not the center of everything!
Galileo studied the sky for the next 30 years. He wrote many books about his discoveries. Near the end of his life, he was arrested for teaching his ideas to others. He died trying to show people that Copernicus was right.
Sir Isaac Newton
Isaac Newton was an English scientist. He made many discoveries. His most important discovery was the law of gravity.
Gravity is the invisible force that pulls everything on Earth toward the ground. Without gravity, we’d all float away!
Newton thought it was gravity that kept the Moon traveling around Earth. He thought the Sun might have gravity, too. That would explain why Earth and the other planets kept traveling around the Sun instead of flying off into space.
Theories are well-tested scientific explanations.
Newton’s ideas about gravity helped people understand and accept the theories of Copernicus and Galileo.
Early As tronomers
Ptolemy
Copernicus
Galileo
Newton
The Big Mistake
Copernicus, Galileo, and Newton were on the right path to understanding space. But they made one big mistake. They all thought that everything in space traveled around the Sun.
Over time, astronomers have learned much more. They’ve learned that far from being the center of everything, the Sun is just another star among billions and billions of stars. And they’ve learned that Earth is a tiny speck in a universe so big it’s almost impossible to imagine.
Hans Lippershey (HAHNS LIP-ur-shay) invented the telescope in 1608. Lippershey was a Dutch eyeglass maker. Stories say he got the idea by watching his children play with lenses for his eyeglasses.
Sir Isaac Newton invented a telescope that used mirrors. A mirror makes it possible for bigger lenses to see farther without distortion.
The Hubble Space Telescope is a telescope that travels in space. It sends pictures of planets, stars, and galaxies back to computers on Earth. The Hubble can see objects that are billions and billions of miles away.
The biggest telescopes in the world are located in Chile. They are operated by the European Southern Observatory and are linked by computers.
The universe is everything there is. It is the Sun and Earth and all the other planets and stars and all the space between them. It is full of dust and rocks and ice and gas. Mostly it is full of nothing—just trillions and trillions of miles of open space.
The Birth of the Universe
The universe was born so long ago that no one knows for sure how it happened.
Today, most astronomers think the universe began with a huge explosion. They call the explosion the Big Bang. They think that it happened about 13.75 billion years ago.
Two things happened at the moment of the Big Bang. First, the stuff that would become everything in the universe came into being. Second, the universe began expanding. That means it went flying in all directions, moving farther and farther away from the spot where the Big Bang happened.
The universe is still expanding today!
Millions, Billions, and Trillions
The universe is huge. We have to use very big numbers when we talk about distances in the universe and the number of stars in the universe.
How much is a million?
A million marbles would fill the inside of a small car!
How much is a billion?
A billion marbles would fill the inside of a two-story house!
How much is a trillion?
A trillion marbles would fill the biggest domed stadium right up to the roof!
It is the open space between bits of matter that expands. The stars, planets, and other matter stay the same size. The universe is like a rising loaf of raisin bread! The raisins stay the same size but move farther apart as the dough rises.
The universe expanded very quickly after the Big Bang. At the moment of the explosion, the whole universe was smaller than the head of a pin. Within a second, it was billions of times bigger than Earth.
For billions of years after the Big Bang, everything in the universe was just very, very hot gas. As the universe expanded and cooled, some of the gas began to clump together. The clumps grew into huge, fiery balls. These balls became the first stars.
Stars and Galaxies
When we look at the night sky, we see just a few of the stars that are in the universe. Even on the clearest night, only about 2,000 stars can be seen without a telescope. Astronomers think there may be as many as 10 billion trillion stars in the universe!
Stars are grouped together in galaxies. Most galaxies contain hundreds of billions of stars.
All the stars we can see are part of a galaxy called the Milky Way. There are more than 200 billion stars in the Milky Way. One of those stars is our Sun.
Some stars are smaller than Earth. Others are 300 times larger than the Sun!
Astronomers measure distances in space in light-years. A light-year is the distance light can travel through space in one year.
One light-year = 5,880 billion miles.
The Sun is the star closest to Earth. It takes light from the Sun about eight minutes to reach Earth. The next closest star is Proxima Centauri (PRAHK-suh- muh sen-TAW-ree). It takes light from Proxima Centauri about four years to reach Earth! So astronomers say that Proxima Centauri is four light-years away.
It takes light from distant stars billions of years to reach Earth. By the time it gets here, the stars are billions of years older than they were when the light left them. So we really see the stars as they used to be! Looking at the stars is like looking into the past.
The Sun is a star like all the other stars in the sky. It looks bigger and brighter than other stars because it is much closer to Earth.
The Sun is 93 million miles from Earth. The next closest star is more than 20 trillion miles away!
The Sun is a medium-sized star. It’s about 865,000 miles in diameter. Compared to Earth, it’s gigantic! Over a million Earths could fit inside the Sun.
Diameter means the distance through the center of a circle or ball.
Heat and Light
The center of the Sun is called the core. The Sun’s core is like a giant fiery furnace. But the fire of the Sun is not an ordinary fire. No ordinary fire could warm Earth from 93 million miles away!
The fire at the center of the Sun is called a nuclear reaction. Due to its enormous heat and pressure, the Sun makes heavier elements out of lighter ones. This process releases lots and lots of energy.
The energy travels from the Sun’s core to the surface. When the energy reaches the surface, it shoots into space as heat and light.
Spots, Flares, and Prominences
Since the Sun is a ball of gas, its surface is not solid like Earth’s. It is always changing, like the surface of a pot of boiling water.
There are often dark patches on the surface of the Sun. These dark patches are called sunspots. Sunspots look dark because they are not quite as hot as the rest of the Sun’s surface. Most sunspots are many times bigger than Earth.
Giant bursts of light and heat sometimes explode above sunspots. These are called solar flares. Solar flares are twice as hot as the surface of the Sun. They are also much brighter.
Sunspots and solar flares send out energy that can affect radio and TV broadcasts on Earth.
Prominences (PRAH-muh-nens-iz) are loops of fiery gas that leap out into space, then back to the Sun’s surface. Prominences can last for many hours.
The Life of the Sun
The Sun is what astronomers call a yellow dwarf star.
As it grows older, the Sun will start to run out of fuel. Oddly, that will cause it to become bigger but cooler. It will also change color. It will become a red giant.
The Sun will slowly lose its heat and light, the same way the burners on an electric stove glow and stay hot after they are turned off.
At the same time, the Sun will get smaller and smaller until it shrinks to about the size of Earth. It will then be a white dwarf.
After it becomes a white dwarf, the Sun will lose all its heat and light. But don’t worry—astronomers think this won’t happen for another 5 billion years!
