Galileo Galilei was the greatest astronomer
of all time. His discoveries in the 16th and 17th centuries
shocked the establishment, including the Catholic Church which, at the time, believed the earth
was the center of the universe. Armed with his telescope and a brilliant mind,
Galileo proved them wrong: the earth actually revolves around the sun. And for this assertion, he would be condemned
to a tragic life. A century before, a Polish scientist named
Nicolaus Copernicus had come up with the unorthodox idea that the Sun was at the center of the
solar system, not the Earth. Called the heliocentric model. Copernicus's theory was just that - a theory. Galileo proved Copernicus was right. He challenged many preconceived notions through
a rigorous process of testing. His reliance on scientific experimentation
may have started with a fascination with pendulums. As a student, he was struck by the steadiness
of a swinging lamp in the Cathedral of Pisa. He noticed that it didn’t matter how far
the chandelier swung, it always took the same amount of time to complete one swing. Galileo used his own pulse to measure time
as there were no wristwatches back then. His experiments with pendulums confirmed that
it took exactly the same time for a pendulum to go back and forth, no matter the distance
it swung. His discovery led to the later invention of
the pendulum clock which some say opened the door for the Industrial Revolution in the
18th century as the development of timekeeping allowed for a faster pace of life. Galileo’s discoveries brought him some fame. He gained a teaching position at the University
of Pisa - the same university where he dropped out a few years earlier. His father insisted he study medicine though
he was more interested in math. He never graduated. While teaching at the university, academics
argued over Aristotle’s belief that heavier objects fell faster than lighter ones. Most scientists agreed with the ancient philosopher. Galileo did not. He reportedly set up a demonstration at the
leaning Tower of Pisa to prove Aristotle and his colleagues wrong. If a heavier object falls faster than a lighter
one as Aristotle maintained, it would look something like this. But Galileo showed that all objects – regardless
of their mass – freefall with the same acceleration. He was right but his smug nature was too much
for his colleagues who felt Galileo got a kick out of proving everyone wrong / humiliating
them for believing Aristotle. His contract at the University of Pisa was
not renewed. Fortunately, he found another teaching position
at the University of Padua He needed the work as his father had died
and he was entrusted with the care of his younger brother Michelangelo Galilei, who
became a composer. During his nearly two-decade tenure at the
University of Padua, his fame increased. In 1600, he met Marina Gamba, a Venetian woman
with whom he had three children out of wedlock, a son and two daughters. Worried that his daughters wouldn’t marry
well, he urged them to become nuns in a convent near Florence despite the fact that he had
run into trouble with the Catholic Church. Galileo had challenged the church’s official
position that the Earth was the center of the universe. It all began in 1609 when he learned of a
simple telescope built by a Dutch spectacle maker. It was a mysterious invention that could make
distant objects appear closer. He soon built telescopes of his own. Some Venetian merchants saw their value as
a navigational tool and were eager to get their hands on them. While they did eventually find their way to
the decks of sailing ships, Galileo’s ambitions extended beyond the seas to the skies. He used his telescope to make startling discoveries. He found that the moon was not a perfect sphere
as Aristotle believed all heavenly bodies were but instead, was full of imperfections. These are Galileo’s own sketches showing
the moon’s valleys, deep chasms, and mountains. He discovered four moons orbiting Jupiter
- the largest planet in our solar system - destroying the notion that the heavens revolved around
Earth. His belief that the Earth wasn’t at the
center of the solar system was solidified when he discovered that Venus went through
phases, just like our moon. The nature of these phases could only be explained
by Venus going around the Sun, rather than the Earth. He concluded that Venus must travel around
the Sun, at times passing behind and beyond it. Therefore, Earth was not the center of the
universe - the sun was. This angered the powerful people in academia
and the church. The majority of scientists and theologians
agreed with Aristotle's view that the Sun, other planets, and stars revolved around Earth. Galileo believed in God and was in awe of
the role that science played in the beauty of God’s creation. He wrote a letter to a student explaining
that his observations did NOT contradict the Bible because scripture was written from an
earthly perspective. But it nevertheless got him into trouble with
the Roman Catholic Church which, at that time, essentially ruled Italy. In 1633, he faced an Inquisition whose purpose
was to prosecute those considered to be enemies of the state. He was interrogated and threatened with torture. He was then charged with being “vehemently
suspect of heresy” and agreed to plead guilty and was forced to recant his scientific discovery
in exchange for a lighter sentence. His punishment was house arrest for the rest
of his life. Authorities banned his book championing his
belief in a sun-centered universe. And he had to stop teaching or otherwise spreading
his ‘heresy’. Galileo spent nine years under house arrest
at his villa in Arcetri near Florence before dying on January 8, 1642, at the age of 77. It took more than 350 years for the Vatican
to formally acknowledge its mistake. In 1992, Pope John Paul II apologized and
officially declared that Galileo was right. Galileo’s work influenced scientists for
generations to come, including Sir Isaac Newton who developed the law of gravity. I did a story about Newton which I’ll link
in my description. Today, astronomers refer to Jupiter’s four
moons as the Galilean satellites in honor of him In the centuries that followed Galileo’s
telescopic observations, telescopes have grown in size and power, revealing secrets of the
universe that even he could never have imagined. If you're passionate about space, my friends
at Curiosity Stream have a wealth of incredible space documentaries including one about the
James Webb telescope, the world’s largest, most advanced, and most expensive telescope
ever. Their space documentaries will enlighten,
entertain, and inspire you to perhaps one day, travel beyond our planet. There are thousands of entertaining documentaries. My favorite is the Redesign My Brain series
on training your brain to improve your attention, memory, and thinking speed. You can sign up for Curiosity Stream for only
$14.99 for the entire year with my custom link. Not month, but year! Just head to curiositystream.com/newsthink
- which I’ll link in my description and pinned comment. Thanks for watching. For Newsthink, I’m Cindy Pom.
