Galileo’s Extraordinary Scientific and Mathematical Journey

"A man does not attain the status of Galileo merely because he is persecuted; he must be right." -- Stephen Jay Gould

Nathan Calvino, Grade 7

Galileo was a scientist and mathematician who believed that the sun is at the center of our solar system. He believed that Copernicus was correct in his description of the universe. From an early age Galileo showed his scientific skills. At age nineteen, he discovered the isochronism of a pendulum while observing the swinging of a lamp hanging from the ceiling of a church. He noticed that "it took the same amount of time for one complete swing" whether the swing was significant or not. By age twenty-two, Galileo had invented the hydrostatic balance.

Galileo was foremost a mathematician. He said “Mathematics is the alphabet with which God has written the universe.” He had this in common with Copernicus. Another thing that Galileo and Copernicus had in common was their Christian faith. Galileo once said “I do not feel obligated to believe that the same God who has endowed us with senses, reason, and intellect has intended us to forgo their use.”

Galileo said “I think that in the discussion of natural problems we ought to begin not with the Scriptures, but with experiments, and demonstrations.” He believed that correct interpretation of the Bible agrees with observed fact. He viewed Nature as a book written in the language of mathematics. This book of Nature and the Bible are in agreement, but they serve different purposes. He said the "Bible teaches men how to go to heaven, not how the heavens go."

Galileo was born on February 15, 1564 in Pisa, Italy. He was the first of six children born to Vincenzo Galileo and Guilia Ammannati. Galileo’s father was a well-known musician and music theorist.

In 1572, when Galileo was eight years old, his family moved to Florence. However, Galileo remained in Pisa and lived with Muzio Tedaldi, a relative of Galileo’s mother. At age 10, Galileo joined his family in Florence and began his formal education at the Camaldolese Monastery. Galileo found the monastic life attractive and he became a novice, but his father wanted his son to become a medical doctor.

In 1581 Galileo was sent by his father back to Pisa to live with Muzio Tedaldi and Galileo was enrolled in the University of Pisa for a medical degree. Galileo left the university in 1585, without a degree.

After Galileo left the University of Pisa he continued the study mathematics. He got a teaching post at the University of Pisa in 1589. There he conducted experiments with falling objects and produced his manuscript On Motion.

His father died in 1591. In 1592, his contract with the university was not renewed. He quickly found a position at the University of Padua, teaching geometry, mechanics, and astronomy. Galileo invented the thermometer in 1593 and the compass in 1597.

In 1604, he published The Operation of Geometrical and Military Compass. In the same year, Galileo refined his theories on motion and falling objects and developed the universal law of acceleration. He began to express openly his support of the Copernican theory.

Galileo made a telescope of his own and in the fall of 1609, he turned his telescope toward the heavens. In March of 1610, Galileo published The Starry Messenger. In 1612, he published Discourse on Boarders of Water. In 1613, he published his observations of sunspots.

In 1616, Galileo was ordered by the Pope not to teach or defend the Copernican theory of a heliocentric universe. He obeyed the order for several years, partly to make life easier, and partly because he was a devoted Catholic.

Cardinal Maffeo Barberini was chosen to be the Pope in 1623. He was known as Pope Urban VIII and he was one of Galileo’s friends. Galileo received permission to write about both the Ptolemaic and the Copernican systems as long as he didn’t promote the Copernican theory.

In 1632, Galileo published the Dialogue Concerning the Two Chief World System, his most important writing. The Church summoned him to Rome for a hearing that lasted from September 1632 to July 1633. Galileo was treated with respect and was never imprisoned. However, in the end he was convicted of heresy and he was put under house arrest for the remainder of his life. These years were productive as he wrote many manuscripts. However, by 1638 he was blind and in ill health.

Galileo died on January 8, 1642 in Arcetri, near Florence, Italy after suffering from fever and heart palpitations. His will indicated that he wished to be buried beside his father in the family tomb in the Basilica of Santa Croce. However, his relatives feared that this would provoke opposition from the Church, so his body was concealed. His body was later placed in a fine tomb in 1737 by the civil authorities against the wishes of many in the Church.

350 years after Galileo's death, on October 30, 1992, Pope John Paul II formally closed a 13-year investigation into the Church's condemnation of Galileo in an address given to the Pontifical Academy of Sciences. Paul Cardinal Poupard, the head of the investigation, said “We today know that Galileo was right in adopting the Copernican astronomical theory."

Galileo should be remembered and honored as an early pioneer in astronomy. Some of his discoveries include:

· that falling objects accelerate at a fixed rate in a vacuum

· that a pendulum can be used to measure time

· that a cannonball travels in a curve called a parabola

· that the planet Jupiter has moons revolving around it

· that the planet Venus has phases just like our moon

On October 18, 1989 the space probe Galileo, named after Galileo Galilei, was launched to study the planet Jupiter. The space probe orbited Jupiter 35 times then in 2003 was driven into Jupiter, deliberately destroyed to avoid contaminating Jupiter’s moon with any of Earth’s bacteria. The probe took close-ups on Jupiter’s rings and found evidence that its icy moons might hold atmosphere.


Related reading: Galileo's Struggle and Vindication

Galileo’s Struggle and Vindication

Gavin Hoots, Grade 7

Galileo was a brilliant astronomer whose discoveries caused him great distress. He was also a man of Christian faith. Ironically, his greatest detractors were educated men in the Church, some of whom were Inquisition judges. Galileo was tried by the Inquisition after his book was published in 1632. The book was titled Dialogue Concerning the Two Chief World Systems. The controversy was over Galileo’s heliocentric cosmology, a conception of the solar system that contradicted the cosmology of Aristotle that was taught in the Catholic universities.

Galileo was born in 1564 in Pisa, Italy. He was the first of six children born to wealthy parents. His father, Vicenzo Galilei, was a lutist and a music theorist who encouraged his son to think about the world in mathematical terms, directing his son towards quantitative description of the results, or basically, the scientific method of experimentation and observation.

Galileo started his formal education in 1574 at the Camaldolese Monastery in Florence. Galileo found the monastic life attractive and he became a novice, but his father wanted his son to become a medical doctor. In 1581 Vincenzo sent Galileo back to Pisa where Galileo studied for a medical degree, but due to financial difficulties he left before earning his degree.

Galileo continued to study mathematics, supporting himself through minor teaching positions. During this time he began his study of objects in motion which he would continue for 20 years. This research led to the publication of The Little Balance, a treatise that brought him fame and gained him a teaching position at the University of Pisa in 1589. Soon after, he took a position at the University of Padua. This was fortunate for him, as his father died in 1591, leaving Galileo with responsibility to take care of his younger brother Michelangelo.

Galileo taught at the University of Padua for 18 years. His lectures were entertaining and drew large numbers of students, further increasing his fame and wealth.

In 1604 Galileo published The Operations of the Geometrical and Military Compass. He was 40 years old. That same year he refined his theory on motion and falling objects and came up with the universal law of acceleration. Before Galileo scientists thought that force causes speed, but Galileo showed that force causes acceleration. Galileo reached the conclusion that bodies fall on the earth at a constant acceleration, and that gravity, which causes all bodies to fall, is a constant force. In other words, a constant force like gravity does not lead to constant speed but to constant acceleration.

Galileo built his first telescope in 1609 after learning how Dutch eyeglass makers had built a simple telescope. He showed his apparatus to some merchants who recognized that it would be useful for spotting ships. The merchants paid him to manufacture several telescopes. In1610 Galileo used his telescope to observe the stars and planets. With the telescope he made discoveries that caused him to question Aristotle’s cosmology. He saw mountains and valleys that indicate changes on the moon. He observed the motion of four of Jupiter's moons. He also observed the phases of Venus, which could be explained only by the motion of Venus around the sun, not the Earth. He published his discoveries in a small volume titled The Starry Messenger.

Galileo understood the implications of his discoveries in physics and astronomy. He wrote,

“My purpose is to set forth a very new science dealing with a very ancient subject. There is, in nature, perhaps nothing older than motion, concerning which the books written by philosophers are neither few nor small; nevertheless, I have discovered some properties of it that are worth knowing that have not hitherto been either observed or demonstrated. Some superficial observations have been made, as for instance, that the natural motion of a heavy falling body is continuously accelerated; but to just what extent this acceleration occurs has not yet been announced... Other facts, not few in number or less worth knowing I have succeeded in proving; and, what I consider more important, there have been opened up to this vast and most excellent science, of which my work is merely the beginning, ways and means by which other minds more acute than mine will explore its remote corners.”

Galileo did not see a conflict between science and the Bible. He believed that both served God and made truth more evident to Humankind. He wrote, "God is known by nature in his works, and by doctrine in his revealed word."

In a 1615 letter to Madame Christina, the Grand Duchess of Tuscany, Galileo wrote, “I think in the first place that it is very pious to say and prudent to affirm that the Holy Bible can never speak untruth—whenever its true meaning is understood.”

Pope Paul V ordered the Inquisition to look into Galileo’s work. The Inquisition ruled against him in 1616.

One of Galileo’s friends, Cardinal Maffeo Barberini, was chosen to be the Pope in 1623. Galileo went to see him, but Urban VIII did not lift the injunction against him. Galileo received permission to write about both the Ptolemaic and the Copernican systems. He did exactly that in his Dialogue Concerning the Two Chief World Systems which was published in 1632. It was regarded as a literary and philosophical masterpiece, but it clearly favored the Copernican cosmology and this lead to further problems with the Church hierarchy.

Again, Galileo was called before the Inquisition in 1633. This time he was forced to renounce his findings and promised never again to write about the Copernican system. He was 70 years old and placed under house arrest. Galileo died on January 8, 1642, after suffering from a fever and heart palpitations.

Galileo’s final work was a volume that detailed his 30 years of work in physics. The book was titled Dialogue Concerning Two New Sciences and many scholars consider it his greatest work. This was written while he lived under house arrest. It was printed in Holland in 1638, but by this time Galileo had become blind from a combination of cataracts and glaucoma.

In 1758, the Roman Catholic Church lifted the ban on writings that supported the Copernican cosmology. By 1835 the heliocentric understanding of the solar system was accepted and taught in Catholic universities.

In 1981 a commission of the Church began to look into Galileo's case, and 11 years later the commission acknowledged that Galileo's judges had erred in their assessment. In 1992 Pope John Paul II acknowledged that the church was wrong to condemn Galileo.

Related reading: Galileo's Christian Faith

Galileo's Christian Faith

Galileo Galilei (1564-1642 A.D.) was a man of Christian faith as well as a man of science.

Galileo expressed his support of the Polish astronomer Copernicus who developed a cosmology with the sun at the center, the Earth rotating about a polar axis, and the Earth and planets circling the sun. Basically this is what we know of the solar system today.

 Galileo shared some of these ideas and expressed views on the Bible in a letter to the Grand Duchess of Tuscany in 1615. In that letter Galileo wrote:  “I think in the first place that it is very pious to say and prudent to affirm that the Holy Bible can never speak untruth—whenever its true meaning is understood.”

Later this letter was used against him in his first Church trial and censure. The Roman Catholic tribunal directed Galileo to stop teaching the Copernican cosmology and forbid him even to discuss it.

In 1632, Galileo completed his Dialogue Concerning the Two Chief World Systems—Ptolemaic & Copernican. In this work he presented the arguments for and against the Copernican (solar centric) cosmology and the Aristotelian and Ptolemaic (geocentric) cosmology. 

Galileo warned the Church hierarchs and theologians about the long-term effects of denying scientifically verified data. He wrote: 

"Take note, theologians, that in your desire to make matters of faith out of propositions relating to the fixity of sun and Earth you run the risk of eventually having to condemn as heretics those who would declare the Earth to stand still and the sun to change position--eventually, I say, at such a time as it might be physically or logically proved that the Earth moves and the sun stands still."

The Roman Catholic Church did not heed Galileo's warning and about 350 years after Galileo, the Vatican issued an apology.

Related reading:  Famous People in Science; Galileo: Misjudged Astronomer; The Trial of Galileo