‘Heroes of Science’: Galileo Galilei, Father of Science and Master of Standing Up for Science

You could easily fill up an entire blog talking about all the lives of the great scientists, the pioneers, the giants’ shoulders who we stand on (so to speak). A hero of science isn’t necessarily the smartest, the most well-funded, or the one with the most papers: a hero of science is someone who has recognized the value of the scientific method as a way towards reaching the truth about how the universe works, and not letting any adversity or barrier stand in the way of making that truth known. With this ‘Heroes of Science’ post series, I want to highlight both my own personal heroes of science as well as scientists that stand out for their contributions to the realm of science and to how we navigate through our own careers as professional scientists.

I was partially inspired for this post series by a recent Science Friday podcast featuring a 1996 interview with the great science communicator Carl Sagan. During his life, Carl Sagan was a proponent of the scientific method and had a great passion for sharing science with everyone. After listening to the podcast and remembering how much I loved reading Contact, I started off on ‘Demon-Haunted World.’ I was surprised to hear in the introduction that two of Carl Sagan’s heroes on his path towards a career in science were his own parents, both of whom were not professional scientists or even had a strong inclination for science. In the book Sagan mentions his parents as a source of fascination balanced with skepticism about the world. He touts this balance as a crucial part of life for any career scientist: to be continually interested in learning more, yet cautious when it approaches. Reflecting on his words—with more on his discussion of the dangers of a world full of pseudoscience featured in next week’s post—led me to  think about my own scientific heroes. I can’t help but think back a long, long time ago to a 16th century Italian astronomer and physicist, called the “father of science”, and a man who stood up for his views on the place of the world within the universe: Galileo Galilei.

'Galileo facing the Roman Inquisition' by Cristiano Banti (1857).

As a disclaimer, this post is by no means an exhaustive biography of the Life and Times of Galileo Galilei, but is meant only as an overview of his life as a scientist and why I feel he is a Hero of Science. The information on his life is based on everyone’s favorite source of fun facts, and certainly there are better sources    than this blog  if you are interested in learning more about Galileo.

But before jumping off to Galileo, let’s set the scene with another scientific giant:  Copernicus. In 1543, just shortly before he died at the ripe old age of 70, the Polish astronomer and mathematician published De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres), a very technical publication using mathematical functions to provide an alternate universal model: one in which the earth revolved around the sun, and not vice versa. With the completion of his seminal work and the first such mention of a heliocentric theory, Copernicus passed away, and unfortunately the immediate impact of his work passed just as quickly. The book was never formally banned but it was removed from circulation soon after initial publication, with a low initial demand due to its technical nature and described as ‘mathematical fiction with no physical reality’.

Jump forward just three years later to 1546, when Galileo Galilei is born and named after his ancestor who was a physician and university professor (no pressure, of course). Galileo went to school to become a physician (OK, maybe there was a little bit of pressure) but he soon realized he had a much deeper fascination for things outside of medicine, concerning questions like ‘why do things move the way they do?’ Galileo asked his father to change to natural philosophy and math, and was given permission (despite the fact that Galileo must have forgotten that doctors earned more money). Galileo soon excelled in a new program, with his skills in applied science, mathematics, and enough of an artistic background to also be an expert of design.

During his scientific career, he taught at the University of Pisa and the University of Padua, penned twelve books, and made numerous discoveries and tools, including the refracting telescope which to this day is still referred to as the Galilean telescope. His efforts were focused on observation, experimentation, and bringing in mathematics to better understanding natural laws. With his new telescope he was able to write the first treatise of observational astronomy, including observing the moons of Jupiter, the roughness of the moon, the Milky Way, and even sunspots. Through his observations he also worked on promoting the Copernican theory of the universe, but was unable to prove the theory at first. He went through theories on tides and comets, but realized that these ideas didn’t fully support the theory of heliocentrism. Nonetheless, he continued to search for scientific and mathematical means to support his claim.

After Copernicus had died, his heliocentric theory was not overly controversial, mainly because the available data, the lack of  stellar parallax, did not support it. A parallax is the phenomenon that occurs when you perceive a shift in the position of a faraway object depending on where you are: try looking at a picture on the far side of the room while closing just your left eye, then closing just your right. Similarly, if the earth revolved around the sun, then there should be observable shift in a star’s location every six months (beyond the changes corresponding with the seasons). The lack of this shift was evidence to many in the 1600’s that the heliocentric theory was invalid, even though Copernicus had argued that the distance was so large that the parallax would be negligible to the naked eye (and it wasn’t until the 19th century that there was even good enough instrumentation to detect it at all).

However, the controversy with the heliocentric theory was more than just where the sun and the earth sat with respect to one another: it was about respect for Papal authority. This was seen as especially crucial in Italy, who had just witnessed the effects of the Counter Reformation after the Protestant uprisings against the Catholic church in the early 1500’s. The heliocentric model was attacked by the Papacy using biblical references which were vague at best, including Psalm 96:10 (King James Version) ‘Say among the heathen that the Lord reigneth: the world also shall be established that it shall not be moved: he shall judge the people righteously.’ Galileo argued that heliocentrism was not in contrast to the bible in his  letter to the Grand Duchess Christina, and he was soon called to Rome by the Inquisition for his Protestant-like threats to ‘reinterpret’ the Bible. He was ordered by the Inquisition to abandon the idea, with works by Copernicus and other authors banned until they could be re-written by the Catholic church.

Soon after Galileo’s papal hand slap, there was a new pope elected, Urban VIII (one who happened to be a friend and fan of Galileo and who had opposed his condemnation) and Galileo chose to stay out of spotlight. While the papacy might have thought him tamed, he instead spent a considerable amount of time building up his arguments on heliocentrism. After nearly twenty years of work and staying away from controversial letters and treatises, he emerged from the shadows and published “Dialogue Concerning the Two Chief World Systems,” his seminal work on the heliocentric theory. He had received formal permission and authorization from the Inquisition and Pope Urban VIII, who had previously requested Galileo to give arguments for both the heliocentric and the geocentric (also called Ptolemaic) theories and to include Urban VIII’s personal views within the book. Galileo did so, although in a way to be sure as not to make either the Inquisition or Urban VIII very happy with the result.

Galileo’s Dialogue  is set up as a debate, with the players being a Copernican supporter Salviati (named after a friend of Galileo), who voices many of Galileo’s opinions directly and who is referred to as the ‘Academician’ in  Dialogue.  Dialogue also features an initially neutral but intelligent man named Sagredo (another friend of Galileo) who offers additional comments and direction throughout the discussion. The last character is Simplicio, who holds to the ways of Ptolemy and also voices the direct opinions of Pope Urban VIII. In addition to putting the words of Urban VIII into the mouth of a simpleton (the connotation of Simplicio from Italian), anyone reading Dialogue sees the clear victor in the discussions being Salviati, and with the book being apparent to any reader not an evenly-balanced dialogue but a direct attack on geocentrism. While Galileo’s arguments on the heliocentric theory using tides as an example were not correct, Galileo’s book did touch on a number of other scientific topics and was clearly directed at Rome and her challenges made against science.

Galileo was called to Rome to defend himself in 1632 immediately after the publication of  Dialogue, where he was forced to admit that he had held onto his Copernican beliefs after his last trial, despite being told to do otherwise. He was found ‘vehemently suspect of heresy’ and was sentenced to imprisonment and to ‘abjure, cure, and detest’ his opinions on the matter. He remained under house arrest for the rest of his life until 1642, and his Dialogue  was banned.  While there is much doubt of him uttering the infamous words ‘and yet it moves’ while being forced to recant his theory during the trial, the urban legend brings to life the power of his story and defiance of papal law. During his imprisonment he was forced to read seven penitential psalms per week, while in his spare time writing summaries of his work which were published in Holland to avoid censorship and are credited as the foundation of modern physics.

While his most controversial arguments on heliocentrism were not founded on observation, he still had numerous contributions to the field of science before his death: work on the science of motion, the mathematical laws of nature, and his support for a separation of science from philosophy and religion, which was a new and turbulent idea in his time. He was also willing to change mind in accordance with observations, understanding that information was crucial to bringing an idea to life. Perhaps that’s why he worked so tirelessly to the tides theory, and a shame that only technology more than 200 years after his time could prove him right. He was also a lover of design and of function, and left behind many practical and beautiful engineering works such as his refracting telescope.

Perhaps the reason Galileo first came to mind for me, however, is his relentless search for the truth even in the face of adversity.  His quest was for knowledge and for scientific truth, and this is what should drive us as scientists. But all too often we are driven by other pressures: for funding, for acceptance of ideas, for pleasing our outside collaborators or PIs. What should drive us is the search for answers to questions, regardless of what those answers are, whether they are what we thought they would be when we first set out. Being a hero of science means adapting your mind and your ideas to what you see, not in adapting what you see to your mind and your ideas.
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To this day, Galileo is still called the Father of Modern Science by more modern scientific greats such as Albert Einstein and Stephen Hawking. And while the Catholic church may have negated his works at first, his legacy stands in a more positive light. In 1939, Pope Pius XII made his first speech to the Pontifical Academy of Sciences and described Galileo as being among the "most audacious heroes of research... not afraid of the stumbling blocks and the risks on the way…" While we probably won't all become future pioneers of modern science as Galileo was, we all have the opportunity to be ‘audacious heroes’ in our own worlds, to stand up and work towards truth, and to meet the challenges as they come with fervor and with courage.

I hope you have enjoyed the start of our Heroes of Science series. If you have a hero, be he or she modern, ancient, or anywhere in between, send your suggestion and a rationale for you choice to our gmail address or leave a message in the blog post. We look forward to sharing more heroic stories in future posts!