Galileo and the Catholic Church

podcast Apr 23, 2018

Why Galileo?

Last Episode we discussed NASA’s latest mission to Europa, the Europa Clipper, and we mentioned that Jupiter’s Moon Europa is one of the 4 Galilean moons. These moons have curious names though.


If you’ve ever wondered where these planets and moons got their names, we trace it all the way back to Roman Mythology. Jupiter, Mars, Saturn, Venus, and Mercury were named after Roman gods because these were the planets that early Romans could see without a telescope. Then, we continued the tradition, for example:


MERCURY: Roman Winged Messenger, winged god of travel because he moves so fast

VENUS: Roman Goddess of Love, no doubt because of Venus's dazzling appearance in the sky

MARS: Roman God of War

JUPITER: Chief Roman God (Jupiter is King of the Gods, an elected position)

SATURN: Former Roman God of Agriculture, retired. Replaced by his daughter, Ceres, which is the name of the Dwarf planet Ceres; the largest object in the asteroid belt between Mars and Jupiter

URANUS: Former Roman God of the Sky who was replaced by his grandson, Jupiter.

NEPTUNE: Roman Lord of the Sea

PLUTO: Roman Lord of the Underworld


The Romans saw Jupiter as the equivalent to Zeus in Greek mythology, and German astronomer Simon Marius named its 4 moons after Jupiter’s lovers, Io, Ganymede, Callisto, and Europa. However, Jupiter has 67 moons and each of them were continued to be named after lovers of Jupiter, and when those names ran out, names of his children were used. Then at long last we sent a Spacecraft there to scope things out and of course NASA named it JUNO, after Jupiter’s wife.

Back to Galileo!

Galileo was the first person ever to discover moons around another planet in our solar system and he did this in the year 1610. He is also credited with first observing the rings of Saturn, the phases of Venus, sunspots on our very own Sun and the shadowed lunar surface. The reason why he is so fascinating for us is his story of discovering and trying to spread this truth that the Earth orbited the Sun, and not the other way around! At every turn he was stopped either by the Roman Catholic Church, by the many other churches branched off from the Reformation who understood the bible to be far too literal to allow for his outlandish ideas, or by people who held true to Aristotle’s and Ptolemy’s geocentric ideas so much that they thought Galileo was heretical and insane.

Galileo's Background

Galileo Galilei was born in Pisa, Italy in 1564. In 1581, he started at the University of Pisa studying medicine, but was soon drawn to the study of mathematics. After school, he went on to become the chair of mathematics at the universities of Pisa and then Padua, centering most of his studies on the mathematics and physics of falling bodies. With that research, he eventually published Du Motu (On Motion), a work that contradicted Aristotle’s views on motion and falling objects. Galileo gave popular lectures to many large crowds which spread his fame and got people talking.

Initial Discoveries

That all being said, it was his homemade telescope that really catapulted him into upsetting the Church and the norm. At this point, everyone KNEW that the Earth was not only the center of our planetary system, but the center of the Universe as well. In 1604, Galileo built his very own telescope. He noticed that moons orbited Jupiter, confirming that not everything orbited the Earth. He also saw that Venus had shadowed phases, but we’re inconsistent and nothing like the Moons. One of his other major discoveries that locked in his belief of a sun-centered or heliocentric system was the Moons bumpy and shadowed surface, that its phases came from our orbit of the Sun! All of this however, contradicted Aristotle’s teachings and the established order defined by the Catholic Church.


In 1613, Galileo wrote a letter to a student basically saying that the Copernican Theory (or the heliocentric) didn’t actually contradict passages from the Bible and that the Sun was indeed the center of the Solar System. This letter was then made public and the Church denounced the Copernican theory, naming it heretical and thus ordered Galileo in 1616 not to “hold, teach, or defend in any manner” the Copernican theory. Galileo obeyed this order for seven years, partly because he was a devout catholic and partly due to relieve pressure and allow him to continue research. Then inn 1623, Galileo’s friend was elected Pope Urban VIII and he allowed Galileo to pursue his work again on the condition that everything written about this heliocentric theory was objective and not proclaiming it as truth. What did he do? In 1632, he published “Dialogue Concerning the Two Chief World Systems” and well, proclaimed it as truth.

Galileo was then summoned to Rome and tried for over a year without cruelty, but when he was finally threatened with torture, he finally admitted to supporting the theory. He was convicted of heresy (or contradicting religious doctrine) and due to his old age, lived the last 8 years of his life under house arrest. It’s said that while supporting the theory would get him arrested and claiming it as truth would lead to graver consequences, still he stood up to his inquisitors before leaving for home and spoke the words "e pur, si muove" or "even so, it does move." Speaking of course of the truth that Earth moves and cannot be the center of the universe. Clearly bypassed or ignored, he was ordered not to have any visitors and not to have any of his works printed outside of Italy and naturally, he ignored both, spreading his works to France and Holland. While under house arrest, ha also wrote “Two New Sciences” and eventually became blind, extremely ill, and died on January 8 1642.

Partially due to the spreading of his works, over 100 years later in 1758, the Church could no longer deny the evidence of opposing scientific explanations dropped its ban on published works supporting the Copernican Theory, and by 1835 the Church disposed of its opposition to heliocentrism in general. Finally in 1992, Pope John Paul II rectified one of the Catholic Church’s most infamous wrongs of condemning Galileo, which was seen throughout history as one of the main pillars separating Science and Religion, of course later confirming that science and religion are in fact complimentary in their explanation and support for theories concerning the beginning of Earth and our Universe.


Patreon Questions:

FLO: Angela Cunningham from Poway CA askes:

1a. How do we decide who has the right to mine, colonize, set up their stuff, etc. on the moon?

1b. If/when there are multiple private entities working/living on the moon, who governs them?

ANSWER: Agreed upon in 1967, and signed by over 50 major countries, the Outer Space Treaty states plainly that anyone can go to the moon, but no nation can claim ownership to any part of the moon. They can set up base there, but no sort of governance has been approved by the UN or outlined in this treaty.

Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies


Article I

"The exploration and use of outer space, including the moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.

Outer space, including the moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law, and there shall be free access to all areas of celestial bodies.

There shall be freedom of scientific investigation in outer space, including the moon and other celestial bodies, and States shall facilitate and encourage international co-operation in such investigation."


Article II

"Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means."


Article III

"States Parties to the Treaty shall carry on activities in the exploration and use of outer space, including the moon and other celestial bodies, in accordance with international law, including the Charter of the United Nations, in the interest of maintaining international peace and security and promoting international co-operation and understanding."


Article IV

"States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.

The Moon and other celestial bodies shall be used by all States Parties to the Treaty exclusively for peaceful purposes. The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military maneuvers on celestial bodies shall be forbidden. The use of military personnel for scientific research or for any other peaceful purposes shall not be prohibited. The use of any equipment or facility necessary for peaceful exploration of the Moon and other celestial bodies shall also not be prohibited."


Article XII

"All stations, installations, equipment and space vehicles on the Moon and other celestial bodies shall be open to representatives of other States Parties to the Treaty on a basis of reciprocity. Such representatives shall give reasonable advance notice of a projected visit, in order that appropriate consultations may be held and that maximum precautions may be taken to assure safety and to avoid interference with normal operations in the facility to be visited."

Join us in our mission!

We've been waiting for you! Join the community and support Space, But Messier! for as little as $1/month! We'll make it worth your while...


50% Complete

Join Space, But Messier!

Sign up here to receive updates about new podcasts episodes, giveaways, news, and everything Space, But Messier!