Category Archives: Galileo

Tips from Galileo on living through a pandemic

One of the many things that history teaches us is the importance of perspective.

When a series of outbreaks of bubonic plague ravaged northern and central Italy from 1629 – 1631 Galileo, who lived in Tuscany, was forced into quarantine. A friend of Galileo’s reflected on the three year period feeling “like a thousand years.”

In 1633, Galileo book Two Systems was banned by the Catholic Church and he was accused of heresy for using science to prove the Copernican theory that the Sun is at the centre of our Solar System. His journey to Rome to attend the trial took over three weeks and included mandatory quarantine.

Galileo was found guilty of ‘suspected heresy’ and sentenced to house arrest for life. During this time his daughter Virginia, who had become a nun in a nearby convent, cared for him remotely by sending him remedies to prevent him from contracting the plague and also regular correspondence to cheer him up.

Living and working through the challenges posed by a pandemic are certainly not new, but we are able to glean some inspiration and knowledge by being attentive students of history. At the very least, we should appreciate that our struggles, and the ways to get through them, are neither new nor unique. The most effective of these now during the COVID19 pandemic, as in Galileo’s time, rely on all communities working together and supporting those who are most vulnerable and struggling the most.

Painting of Marseille during the plague. (Credit: Robert Valette/Wikimedia Commons)

Perpetual motion: a long history

Since the dawn of technology, humans have sought ways of using machines and inventions to make work easier. Even though we can use machines to create mechanical advantage, it is sadly not possible for any machine to produce more energy than is put into it. As Albert Einstein put it, “Energy cannot be created or destroyed, it can only be changed from one form to another”.

Galileo Galilei never explicitly expressed his thoughts on perpetual motion machines, however, we can see from several of his lecture notes, made while a professor at the University of Padua in Venice, that he clearly understood that perpetual motion machines are indeed not possible. As he eloquently put it, “Nature cannot be deceived”.

When discussing this principle, Galileo used the analogy of drawing water from a well by hand with a bucket. He conjectured, “whoever believes they are able to draw a greater amount of water from a well, in the same time, with the same force is in grave error”.

Leonardo da Vinci sketched a hypothetical perpetual motion machine (pictured here). Hundreds of years before theories of thermodynamics were developed, he understood that despite its allure, such a machine was impossible. He wrote; “Oh ye seekers after perpetual motion, how many vain chimeras have you pursued? Go and take your place with the alchemists.”

Galileo’s Icy Moon

Four hundred years ago Galileo made a discovery that fundamentally shaped our understanding of the universe and our place in it. Using his powerful telescope he observed that the planet Jupiter had moons, which he initially thought to be planets.

In March 1610, Galileo published his discoveries of Jupiter’s satellites and other celestial observations in Siderius Nuncius (The Starry Messenger). The scientific proof supported the Copernican heliocentric theory that the Sun is at the centre of the Universe, not the Earth.

NASA’s recently published photos, taken by the Juno Jupiter probe in December 2019, have provided us exciting new insights into the largest moon in the solar system.

According to Alessandro Mura, a Juno co-investigator at the National Institute for Astrophysics in Rome, the mapping of the north polar regions of the icy satellite Ganymede in infrared light has revealed a “phenomenon that we have been able to learn about for the first time with Juno because we are able to see the north pole in its entirety. The data show the ice at and surrounding Ganymede’s north pole has been modified by the precipitation of plasma.”

Image of Ganymede’s Trailing Hemisphere by the NASA Jet Propulsion Laboratory

Galileo’s Thermometer

Have you ever wondered why a boat made of steel floats in water while a solid bar of steel sinks?
You might also wonder how the measurement of heat is related to buoyancy.

At the start of the 17th Century, scientists wracked their brains to find a way to accurately detect the temperature of a body, air, and liquid. The thermometer was the answer. The principle of buoyancy on which it is based was discovered by Archimedes of Syracuse however, Galileo developed experiments to prove that the density of a liquid changes in proportion to its temperature.

The earliest design of these instruments attributed to Galileo is known as a thermoscope and dates back to 1597.

Many instruments designed by the Accademia del Cimento, Europe’s first society exclusively dedicated to Science, are on display at the Galileo Museum in Florence.

As we know today, temperature measurement is important for medical practice, manufacturing, and scientific research.

Photo: A very delicate glass spiral thermometer designed by the Accademia del Cimento, of which Galileo was a member, is on display at the Galileo Museum in Florence.

Galileo the Astrologist

Did you know that Galileo read people’s horoscopes as a side business?

In Europe during the late Renaissance Astrology played a very important role for many people and was highly regarded as a “science” alongside Astronomy and Mathematics.

Military generals and noblemen would choose a particular date for their wedding or plan an important battle on a specific ‘lucky day’ based on their horoscope readings.

This is where the term if the stars align, meaning if everything goes really well, comes from.

Galileo, the grandfather of clocks

In Galileo’s time, clocks weren’t very accurate or reliable. They were regulated by small rods driven back and forth by a weight attached to a cord. The clock’s speed was adjusted by moving the small weights that hung from the rod.

Following the death of Galileo’s father in 1591 the famous French polymath Marin Marsenne, who was a good friend of the family, kept in contact with Galileo. The two corresponded for many years discussing their academic research and scientific discoveries. Marsenne later shared Galileo’s work on the motion of pendulums with Dutch physicist Christian Huygens, whose improved design resulted in the first pendulum clocks being built in the 17th Century.

Pendulum clock (clock face), fabricated by Thuret a Paris to a design by Christian Huygens 1657. The Hague, Netherlands.

Newton and the apple

When scientist and polymath, Isaac Newton famously said “if I have seen further it is by standing on the shoulders of giants“, one of the giants he was referring to was Galileo.

Newton (1643-1727), who emerged as one of the greatest minds of the 17th century, discovered the laws of motion and described gravity.

A century earlier Galileo proved that objects fall at the same speed regardless of their mass. Newton understood that this phenomenon also worked in space and used mathematics to prove that the whole universe is governed by the same laws of physics. Gravity effects a falling apple in the same way as it effects an orbiting planet.

Galileo and the Science Deniers

A new biography about Italian scientist, astronomer and mathematician, Galileo Galilei, makes a compelling argument that is as important today as it was 400 years ago. In Galileo and the Science Deniers, Mario Livio reveals Galileo’s courage and the personal struggles he endured throughout his life because of his unwavering search for the truth supported by science.

It seems unthinkable now because we take certain scientific facts for granted, but in 1633 Galileo was tried, convicted, and sentenced to house arrest by the Catholic Church. His “crime” was to challenge the widely-held belief that the universe was a creation of God, with the Earth firmly located at its centre. Thanks to Galileo and his powerful telescope, he was able to prove that the Earth is one of the many planets that rotate around the sun.

Each beautifully written and insightful chapter delves into the discoveries for which Galileo has been named the father of modern science.

Adam Riess, Nobel Laureate in Physics, writes of the book;

It is fashionable to invoke Galileo on both sides of any debate to claim the mantle of truth. In Galileo and the Science Deniers, Livio teaches us the method by which Galileo found the truth – a process more powerful than rhetoric – examination.  Today more than ever we need to understand what made Galileo synonymous with finding the truth.

Mario Livio, author of Galileo and the Science Deniers, is an internationally renown astrophysicist. His best selling books include The Golden Ratio and Brilliant Blunders.

Galileo’s professional rivalry

While teaching as head Mathematician at Padua University, Galileo became embroiled in an ongoing and heated public debate with his colleague Cesare Cremonini, a renowned Natural Philosopher.

Cremonini, who followed the Aristotle school of belief that the planets (including the sun) orbit the Earth publicly denounced Galileo writing; It is hard to realize what a fundamental blow to all Natural Philosophy it would be if a mere Mathematician could prove actual change in the heavens.

As Cremonini believed that heavenly bodies were created by God, he argued that Galileo’s measurements could not be accurate because he was using mortal instruments to measure the divine.

Galileo responded by publishing a well-reasoned discussion, in colloquial dialect rather than high Latin, between two rural peasants.

One of the peasants remarks: When it comes to measuring things we shouldn’t trust Philosophers, after all, what have they ever measured? We should instead trust in the measurements of the Mathematicians who care not whether something is fashioned from the divine or from polenta, because their measurements will still hold true.

Did you know that Galileo was the first scientist to measure heart rate?

At a young age, while watching a lamp swinging in the Pisa Cathedral, Galileo discovered that each full swing of a pendulum takes exactly the same amount of time regardless of whether the arc of the swing is wide or narrow. He used his own pulse to measure the time of each of the lamp’s swings. Many years later after studying medicine at the University of Pisa he used this knowledge to create the Harmonic Oscillator, a machine that accurately measures the human heart rate.