Lesson 22:Galileo

HOUGHTON MIFFLIN

y Tony Pucci
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Galileo saw stars that we can still see today.
Through the Looking Glass
This is a story of courage. One brave man and his telescope
changed the world. His name was Galileo (gal ih LAY oh).
Most people are full of wonder when they look at the night sky.
The sky probably filled Galileo with wonder, too.
Great thinkers of the past wanted to study the moon,
stars, and planets. It was hard to do this before the telescope
was invented.
2

So these thinkers made up their own ideas about the
universe. They based their ideas on beliefs, not on facts.
Galileo changed all that. He shocked the world with what
he saw using his telescope.
Galileo: From Student to Teacher
Galileo was born in Italy in
1564. He was the oldest of seven
children. His father was a music
teacher. Galileo’s father knew that
his son was very smart. He wanted
Galileo to be a doctor. So at age 11,
Galileo went to school. Priests
lived and taught at his school.
Galileo studied there for six
years. Then he decided to become
a priest, too.
His father did not want
Galileo to be a priest. He sent
Galileo to the University of Pisa to
become a doctor. But Galileo didn’t
want to be a doctor. The only class
he liked was math. The rest of his
grades were low. Galileo dropped
out of school. His father was
very disappointed.
Galileo made many
scientific discoveries.
3

statue of Aristotle
Aristotle was one of the greatest thinkers of all time.
Galileo needed a job. So he helped students with their
math. Galileo worked very hard. A few years later, he returned
to the University of Pisa. This time he was a math professor, not
a student. Galileo was very good in math. But the school made
him pay several fines.
4

Galileo had to pay the fines because he refused to wear a
black robe. All the school’s teachers were supposed to wear one.
Imagine the school’s frustration with Galileo!
At that time, people at the university debated the idea of
gravity. Gravity is the force that
pulls on objects. They also talked
about Aristotle, who lived long
ago in ancient Greece. Aristotle
was a famous teacher and thinker.
Suppose someone dropped
two balls at the same time.
Aristotle said that gravity made
the heavier ball land first. This
seemed to make sense. People
accepted this idea, or theory,
as fact.
Galileo was different.
He wasn’t sure this idea was
really true. Galileo liked to do
experiments. He wanted to
prove an idea was a fact first.
Only then would he believe it.
Galileo decided to test Aristotle’s
theory about gravity.
The Tower of Pisa still
The conditions for Galileo’s stands today.
experiment were simple. First, he
needed to find a tall building. He
chose the tower of Pisa.
5

telescope
lens
Galileo’s telescope made him rich and famous.
The Tower of Pisa lurched, or leaned, a bit, so it wasn’t
truly vertical, or straight up and down. Still, it would do. Then
he needed balls of different weights to drop.
Galileo climbed to the top of the tower. He dropped two
balls of different weights at the exact same time. What do you
think happened Both balls hit the ground at the same time.
Aristotle was wrong. Galileo had just proved it.
It is not known if Galileo really did the experiment in
this way. But we do know that people still believed Aristotle’s
theory! No one praised Galileo for his experiment. In fact, he
got fired from his job. But Galileo was very talented. He quickly
got a new teaching job at another school. It was one of the best
schools in all of Europe.
6

The Telescope
Galileo was happy at his new job. He earned a good salary.
Still, he needed more money. His father was now dead, so
Galileo was head of the family. To earn more money, Galileo
invented many things. His inventions earned him the money
he so badly needed. But one invention changed his life — the
telescope.
A Dutch eye doctor invented the first telescope by accident.
It let him see things far away more clearly. Galileo heard about
it. He was very excited. His instinct, or natural feeling, told him
that this invention was very important. Galileo never saw the
doctor’s telescope. But he built one that worked much better.
As a result, many people think of Galileo as the inventor of
the telescope.
Galileo began to study the night skies with his telescope.
When he looked at the moon, he saw something shocking.
Aristotle said long ago that the surface of the moon was barren,
or empty, and smooth. But Aristotle was wrong again. The
moon has deep valleys and high mountains.
Galileo also looked at the sun with his telescope. He
saw that it had dark spots. Today, we call these dark patches
sunspots. Gases on the surface of the sun explode and cause
these spots. Galileo spent so much time looking right at the sun
that it likely damaged his eyes.
7

Jupiter
Galileo made discoveries about Jupiter with his telescope.
Galileo was also surprised when he looked at Jupiter. It had
four moons moving around it. That seemed impossible! Galileo
saw rings around the planet Saturn. He also saw more stars
with his telescope than he could see with just his eyes.
8

Galileo’s discoveries were a sensation. In today’s world,
his face would be on the cover of every magazine. People were
impressed with his findings.
Galileo’s New Ideas
Galileo wrote a book about his findings. It was called
The Starry Messenger. It was a huge hit. In the book, he said that
many of Aristotle’s ideas were wrong. This was a surprise to
many readers. Galileo also hinted that Aristotle was wrong
about Earth being the center of the universe. That was the
biggest surprise of all.
Galileo now had plenty of money. So he quit his teaching
job and moved to Florence. People throughout Europe called
Galileo a great inventor and scientist. But some people didn’t
like what he had to say. Some of his findings angered the
Catholic Church. Galileo needed to be careful.
Galileo’s Split with the Church Widens
Galileo did not mean to cause problems for the Church.
He was a just a scientist looking for facts. But the Church used
Aristotle’s ideas as a part of its teachings. So some people
thought he was attacking the Church when he said Aristotle
was wrong. Galileo was headed for trouble.
9

Maria Mitchell’s
Comet
Maria Mitchell was born in
1818. Her father was a teacher.
He taught Maria about the
stars and planets. He wanted
her to follow her interest
in math and astronomy.
One night, Maria saw
something unusual when she
looked through her telescope.
She saw a new star in the sky.
Maria Mitchell
She was sure it had not been
discovered a comet there the night before. The
with her telescope.
next night the star was in a
new place. What was this elusive star that was so hard to
find Maria Mitchell had discovered a new comet! A comet
looks like a fuzzy star with a tail of light. People now call
her discovery “Miss Mitchell’s Comet.”
Later, Maria Mitchell became the first woman
professor of astronomy in the United States. She received
many awards. Some say she was the most famous scientist
of the 1800s.
10

Aristotle’s theory was that the earth was the center of the
universe. People still believed him. So did the Church. But one
man had a different idea. His name was Nicholas Copernicus
(kuh PERN ih kus).
Copernicus was a doctor. He wrote a famous book in 1543.
In it, he said that the sun was the center of the universe. The book
also said that Earth moved around the sun. At the time, it was
only a theory. But Galileo’s work now proved this theory. Serious
objections arose, or came from, the Church. The Church leaders
believed that the Bible supported the views of Aristotle.
Copernicus thought that Earth moved around the sun.
The Solar System
11

Galileo agreed with Copernicus. Some people didn’t like
that. One woman from a powerful family attacked Galileo.
She said that he was wrong because the things he observed
went against the teachings of the Bible.
Galileo tried to calm people down. He explained his
ideas in a letter to a friend. He agreed that the Bible couldn’t
be wrong. But he thought the people who interpreted, or
explained, the Bible could be wrong. He also hinted that Church
leaders could make mistakes explaining the Bible. These words
would come back to haunt him.
The Church Investigates Galileo
A few years later, the Church leaders called Galileo to
Rome. This was a bad sign. The Church was very powerful
in those days. Their rulings had the force of law. Church
leaders remembered Galileo’s letter. They accused Galileo
of a crime called heresy (HAYR uh see). Heresy is a belief in
false teachings.
A person found guilty of this crime could get a harsh
punishment. Church leaders often sent them to prison.
They usually took away all of the person’s belongings, too.
Sometimes, a person who did not admit his or her guilt
was killed.
Galileo had to answer many questions. This questioning
went on for days. Finally, the Church leaders found Galileo
innocent. But they did not like Galileo’s ideas. They also said
that Copernicus’s ideas were “foolish.”
12

Punished for Heresy
Before Galileo, the Church
found a man named Bruno guilty
of heresy. Bruno said that the sun
was the center of the universe.
This was a crime. Church leaders
sentenced Bruno to death.
Church leaders punished a man
named Bruno for heresy.
Church leaders made it against the law to read
Copernicus’s book. They said it was a crime to say that the sun
was the center of the universe. The Church told Galileo not to
discuss this idea as a fact. If he did, they would send Galileo
to prison. The Church also told him not to defend Copernicus.
Galileo Returns to Work
Galileo went back to his telescope. He still wrote about
what he found. Church leaders kept a close eye on his work.
Three bright comets appeared in the sky in 1618. Galileo hoped
that these comets would prove that Copernicus was right.
But Church leaders disagreed with Galileo.
13

Galileo’s Career
1564: Birth of Galileo
1581: Student at University of Pisa
1589: Begins teaching at University of Pisa
1592: Goes to University of Padua
1609: Invention of telescope
1610: The Starry Messenger published
1615:
Accused of heresy; told not
to defend Copernicus
1632: Galileo’s second book published
1633: Sentenced to life imprisonment
1642: Death of Galileo
14

Then, a good friend of Galileo became the Pope. The Pope
is the head of the Catholic Church. Galileo saw this as a chance
to make friends with Church leaders. He visited the Pope many
times. Still, his old friend did not support Galileo’s viewpoints.
Galileo was disappointed. Yet, he thought there was still a way
to write about the ideas of Copernicus. Galileo decided to
present the ideas as theories, not as facts.
The Trial
In 1632, Galileo wrote another book. It was a fictional story.
In it, three characters talk about Copernicus’s theories. The
smartest character agrees with Copernicus. The second one has
an open mind. The third character will not change his mind
about anything.
The book was a huge success. A Church leader approved
the book before Galileo published it. But the Pope stopped the
printer from making more books. He thought Galileo broke
his promise not to write about the ideas of Copernicus as facts.
Church leaders called Galileo to Rome again.
Galileo was sick at the time. He asked the Pope to delay his
trial. But Galileo’s old friend refused. He said Galileo had to go
to Rome. Otherwise, Galileo would be put in chains and forced
to come.
15

The Search Goes On
Today, people use telescopes that are much more
powerful than the ones Galileo used. One group uses them
to search for life on other planets. Jill Tarter is the leader
of this group. In all likelihood, Tarter has looked through
a telescope more than anyone else.
Jane Jordan works with Tarter. Jordan is building a new
telescope. This one will see farther into space than ever
before. Maybe these scientists will make discoveries that
change the way we view the world. That’s what Galileo did.
Galileo’s second trial lasted about two months. He hoped
to get a light sentence. He tried to explain his book to the Pope.
But the Pope wouldn’t listen. Church leaders found Galileo
guilty of heresy. They sentenced him to spend the rest of his
life under house arrest. He could never leave his home again.
Church leaders also forced him to admit that Earth did not
move around the sun. Today, we know that it does.
The Final Years
After the trial, Galileo slowly made his way back home.
He was now a decrepit man. Galileo was old, feeble, and sad.
He could never talk about Copernicus again. Still, Galileo went
back to work. Near the end of his life, Galileo went totally blind.
He died in 1642.
16

Almost 200 years later, Church leaders finally looked
at Galileo in a new light. They lifted the ban on his books.
We now know that Galileo was right all along. The sun, not
Earth, is the center of the universe. In 1992, new Church leaders
declared that Galileo was innocent of all crimes.
Journey to Jupiter
In 1989, NASA sent a U.S. spacecraft to explore Jupiter.
They named the spacecraft Galileo. This name honored the first
person to see Jupiter through a telescope.
The Galileo traveled through space to get to Jupiter. It took
six years to get there. A smaller spacecraft launched from the
Galileo landed on the planet. It sent a lot of information about
Jupiter back to Earth.
A large team of scientists studied the Galileo’s findings.
They learned a lot about Jupiter and its moons. Long ago, Galileo
saw that Jupiter had four moons. We now know that Jupiter has
63 moons. There may still be more moons to discover!
Galileo Today
People say Galileo was one of the founders of modern
science. He was unlike most scientists before him. He used
experiments to find the truth. He knew the difference between
a theory and a fact. The things he saw changed the way people
looked at the universe.
17

astronaut
What would Galileo say if he knew that
humans walked on the moon
Today, a space station moves around the Earth. Do you
think this would surprise Galileo What do you think he would
say about the future of space exploration What do you say
about its future
18

Responding
TARGET SKILL Conclusions and
Generalizations How did Galileo’s telescope
change the world Copy the chart below.
Write your conclusion at the bottom. Then list
examples that support your conclusion.
Galileo saw
that Saturn
had rings.
Galileo saw
that Jupiter
had four
moons.
Examples:
Conclusion:
Write About It
Text to Text Galileo’s findings caused problems
with Church leaders. Think of another book
you have read about someone’s ideas causing
problems. Write a paragraph that explains how
the character in that book solved the problems.
19

TARGET VOCABULARY
arose
barren
conditions
decrepit
elusive
frustration
harsh
instinct
lurched
vertical
TARGET SKILL Conclusions and
Generalizations Use details to explain ideas that
aren’t stated or are generally true.
TARGET STRATEGY Monitor/Clarify As you read,
notice what isn’t making sense. Find ways to figure
out the parts that are confusing.
GENRE Narrative Nonfiction gives factual
information by telling a true story.
Write About It
In a famous quotation, Aung San Suu Kyi said,
“Please use your freedom to promote ours.”
What freedoms do you value most Why Write
a letter to the editor of a Burmese newspaper
explaining the freedoms you have and why they
are important to you.
20

Level: W
DRA: 60
Genre:
Narrative Nonfiction
Strategy:
Monitor/Clarify
Skill:
Conclusions and Generalizations
Word Count: 2,592
6.5.22
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