You're watching FreeSchool! Today we're going to learn about the famous
astronomer, Galileo. Galileo Galilei, commonly known simply as
'Galileo,' has been called the father of modern astronomy, modern physics, modern science
and the scientific method. He was an astronomer, inventor, a physicist,
and an engineer. Galileo was born on February 15, 1564, in
what is now Pisa, Italy. He was the oldest of six children born to
Vincenzo Galilei, a musician and composer, and Giulia Ammannati. As a young man he considered joining the priesthood,
but his father wanted him to study medicine instead. At age 17 he enrolled in the University of
Pisa and began his studies. While there, he happened to hear a geometry
lecture by chance, which kindled a love of mathematics. He persuaded his father to allow him to change
his course of study - even though mathematicians were not as well paid as doctors - but had
to drop out of college in 1585 because he ran out of money. Despite this, Galileo continued to study mathematics,
the natural sciences, and art. A few years later he began teaching at the
Academy of Arts and Drawing in Florence, and was later appointed to the chair of mathematics
in Pisa. After his father's death in 1591, Galileo
got a job in Padua, teaching geometry, mechanics, and astronomy. Throughout all this, Galileo was beginning
to make scientific discoveries. He invented a hydrostatic balance, to accurately
measure small quantities. He constructed the thermoscope, a kind of
early thermometer. He developed a water pump that became the
basis for modern pumps. He also developed the plans for the first
pendulum clock. Galileo is most famous, however, for his improvements
to the telescope. Contrary to popular belief, he is not the
inventor of the telescope - no one knows who first invented it. The first patent for a telescope was filed
in 1608 in the Netherlands, by spectacle maker Hans Lipperhey. These early spyglasses only magnified things
three times. Galileo heard about them in 1609 and decided
that he could do better. He reproduced the original spyglass within
a day, and within months, he had a telescope that magnified his view by eight times. Finally he produced one that magnified twenty-three
times, and it is with this telescope that he began his astronomical observations. On November 30, 1609, Galileo used his new
tool to look more closely at the moon, with surprising results. At the time, the moon was thought to be smooth
and perfect, like a gemstone. Upon closer inspection, Galileo realized that
the moon had mountains, and craters. Just over a month later, on January 7, 1610,
Galileo wrote that he had made a strange discovery near Jupiter. He saw what he described as three stars, so
small they were nearly invisible, next to the planet. Over the next few days he observed them moving
in a way that did not make any sense, if they were actually stars. The only thing that would make sense, was
if they were orbiting Jupiter. When Galileo announced these findings, it
caused an uproar. At the time, it was believed that all heavenly
bodies circled the Earth, not something else. Many astronomers at first refused to believe
that such a thing could be possible! Soon, though, Galileo's discovery was confirmed
by astronomers in other observatories, and everything began to change. Next, Galileo turned his telescope on Venus. It was believed, since Venus was thought to
orbit the Earth, that it could not display all of the phases that the moon did, only
some of them. When he found that Venus did go through all
the phases, Galileo realized that the only explanation for it was that Venus orbited
the Sun. Once again, Galileo's discovery caused an
uproar among astronomers. As a result, most astronomers changed their
view of the universe. Instead of everything orbiting the earth,
they thought, perhaps most of the planets orbited around the sun, and then the sun and
moon orbited around the earth. It seemed that everything Galileo observed
with his telescope had something new to show him. He observed the rings of Saturn, although
he could not tell what they were. He saw spots on the sun. He discovered that the cloudy stretch of the
Milky Way was actually made up of closely packed stars too far away to be seen by the
naked eye. Not everyone was happy with Galileo's new
ideas about the universe. At the time, the Catholic Church taught that
the earth was immovable, and that everything in the heavens must rotate around it. Galileo's assertion that things were orbiting
around the sun was therefore contradicting the teachings of the Church. In 1616, he was called before the Roman Inquisition
and put on trial. He was ordered to abandon his ideas that some
objects circled the sun, and never to teach them again. Galileo obeyed - for a while. As he continued to study the heavens, he became
convinced that the earth, in fact, orbited the sun. In 1632 he wrote a book in which he described
why he thought this. This was considered heresy by the church,
directly opposing what they taught. Galileo was put on trial again, and forced
to recant, or publicly deny, his belief that the earth went around the sun. According to popular legend, he then muttered
the famous phrase, "And yet, it moves!" Galileo was sentenced to house arrest for
the rest of his life. Although confined to his home, Galileo did
not stop his scientific investigations. He focused more on physics and mechanics,
continuing to publish his writings until he went blind in 1638. On January 8, 1642, at the age of 77, Galileo
died. Due to his disfavor with the church, he was
originally buried in a small room in the Basilica of Santa Croce. Nearly a hundred years later, after attitudes
had changed, a monument was built in the basilica in his honor and he was reburied near it. Today, Galileo is regarded as a pioneer of
modern science. His insistence on conducting experiments and
relying on observation instead of what he was told by others helped create the modern
scientific method. His contributions to the fields of physics,
astronomy, cosomlogy, mathematics, and philosophy has formed the foundation of many of these
sciences. During his lifetime, Galileo paid a high price
for these discoveries, but today he is considered one of the most important figures in the history
of science. I hope you enjoyed learning about Galileo
Galilei today. Goodbye till next time!
