Without a doubt, Galileo Galilei changed our world and the view of how our world fit into the cosmic scheme of things.

Galileo wasn't the first person to suggest Earth and the rest of the planets circled the sun, known more formally as the heliocentric theory, but he certainly proved it was true. All it took was a small, narrow tube with a couple ground lenses, patient and persistent observations, and a lot of guts. It was 400 years ago Galileo more or less accidentally turned his telescope skyward to the moon and the geocentric theory that the Earth was the center of the universe became an endangered species.

Galileo was born Feb. 15, 1564, in Pisa, Italy, the oldest of seven children. His father was a musician and his mother was a woman of high society who constantly tormented her husband for not making enough money. No wonder he wanted to get away with the boys and play music.

Anyway, when Galileo was eight years old, his family moved to Florence, Italy, but left him behind with a tutor. Maybe his folks realized he was something special and didn't want to interrupt his education. Two years later, he reunited with his family. Being a good Catholic boy, he considered becoming a priest. His father also urged him to become a doctor. He attended the University of Pisa and graduated with a degree in mathematics.

In 1592, Galileo became a professor of geometry, astronomy and mechanics at the University of Padua and had a pretty good life, although as it is now with teaching at any level, he didn't make a lot of money. He was always looking for ways to make more money. Maybe that was his mother's influence.

At age 45, Galileo traveled to Venice in search of wealth and fame. Shortly after he arrived, he heard of the discovery of an optical device that permitted one to see distant objects. Hans Lipperhey, a Dutchman, was said to have invented the telescope in 1608, although there is some contention about that. Galileo was kicking himself because he had the idea to invent a telescope years earlier.

Right away, his wheels started turning and turning fast. He realized the tremendous military usefulness of a telescope. You could see ships approaching in the distance that you couldn't see with the naked eye. As it turned out, Hans Lipperhey had the same idea and had an appointment with the Doge of Venice to sell him and the rest of the Venetian leadership on the value of the telescope.

Luckily, Galileo had a buddy who worked in the Doge's office who suspended all of the Doge's appointments indefinitely. That allowed Galileo to scramble back to his workshop in Padua, where in August 1609 he independently reinvented the telescope using many combinations of lenses.

In less than twenty hours he was successful. He rushed back to Venice, and with the help of his buddy, got an audience with the Doge. He demonstrated his telescope to the government and military brass and became rich and famous on the spot.

It was in fall 1609 that Galileo began changing things forever.

One night, he was on the roof of his house and checking out church domes in the distance when he just happened to slew his telescope in the direction of the moon. That was a special moment in the history of humankind. Even though the view of the moon through his 20 to 30 power telescope was fuzzy, he could see without a doubt that the moon had craters and mountains. It wasn't a perfectly smooth heavenly body. Ever since the time of Aristotle almost 2,000 years earlier, it was believed that all heavenly bodies were smooth and perfect.

Galileo didn't stop with the moon though. He looked all across the night sky and made amazing discoveries with his crude telescope. Even though he was Catholic, he believed the sun — not the Earth — was the center of what was then thought of as the universe. Being the good scientist, he strongly believed theories had to be proved with observations.

He spent long hours observing the moons of Jupiter circling the planet, he observed the phases of Venus, and he saw sunspots on the "perfect sun." He saw countless stars that make up the Milky Way galaxy. He observed that Saturn was a planet that had ears. Unfortunately, his telescope wasn't sharp enough to resolve the ring system of Saturn.

It was his long hours of watching Jupiter's moons and Venus's phases that lead him to conclude that the Polish astronomer Nicolas Copernicus, who died shortly before Galileo was born, was absolutely correct in proposing the Earth was orbiting the sun. Unfortunately back then, it was a very dangerous time to take on the Italian government and the Catholic Church. The church fervently believed in an Earth-centered universe, and any other thinking was considered extreme heresy. In fact, Copernicus didn't release his book on his heliocentric universe theory until the day he died for fear of the Church.

In 1600, the Italian philosopher Giordano Bruno was burned at the stake naked because not only did he believe in the sun-centered solar system, but he also believed there could be other worlds like Earth out among the distant stars.

So when Galileo published his findings later in the 1600s, he got into a lot of trouble. I think he added insult to injury, though, when he indirectly made fun of current Pope Urban VIII in his major publication "Dialogue on the Two World Systems" released in 1633. He was arrested and put on trial. No one really knows exactly what happened at the trial, but it's said he knelt before government and religious officials and claimed he was in error, although deep down he held on to his beliefs. Living in a dungeon the rest of his life or being a human barbecue caused him to recant. Nonetheless, he was convicted of heresy and was kept under house arrest until his death in 1642.

Fortunately, Pope John Paul II exonerated Galileo many years later in 1992, and in fact, he honored him. The Pope said the Bible is a book about how to get to heaven and not how the heavens go.

Galileo changed science, philosophy, culture and religion. He and his small telescopes opened our eyes like they've never been opened before.

Last year I was fortunate enough to visit Italy and the city of Florence. In Florence, there is the Museum of Science, which actually has two of Galileo's early telescopes on display. You also can see Galileo's middle finger bone encased in a helium-filled capsule. The rest of Galileo's remains are entombed in the nearby Basilica of Santa Croce.

If you ever have the chance, travel to Florence and check out Galileo's telescopes. It was an absolutely magic moment in my life seeing those telescopes in the glass case. I felt very close to absolute greatness!

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, "Pennsylvania Starwatch," available at bookstores and at his Web site www.lynchandthestars.com.

Galileo Galilei's remains are entombed in the Basilica of Santa Croce in Florence, Italy.