Galileo's Telescope Observations, and the Name of our Newsletter

I do not feel that the same God who has endowed us with sense, reason and intellect has intended us to forgo their use.” Galileo

Many people mistakingly think that Galileo invented the telescope. In fact he didn't, but he was the first person to point the telescope skyward at night and make observations. These observations would challenge the very beliefs and teachings of the Christian church – and change the way we looked at the universe forever.

The first known telescope was made around the beginning of the sixteenth century by a Dutch lens grinder named Hans Lipperhey. Being an inventor and a scientist himself, Galileo was curious to see what this new telescope could show him, and very soon, he turned his invention to the heavens.

To set the stage for our story, the Christian church had decided that the Ptolemaic view of the universe was the one which was correct, and they openly stated it because it fit with their interpretation of the Bible itself. Ptolemy's universe had all celestial bodies revolving around the Earth. Furthermore, all the stars and planets were perfect and unchanging spheres. These beliefs were accepted by the church and to challenge them, was heresy. The everyday person simply accepted these ideas as fact, after all, they made sense, the Sun, Moon and stars rose, moved across the sky and then set beneath the Earth. To most people, an Earth centered universe were obvious fact.

Galileo Galilei was a mathematician and inventor, born 1564 in Italy and he lived in a time when science was in its infancy. Indeed, it was Galileo who invented the scientific method of setting forth a hypothesis and conducting thorough experiments to test that idea.

Now it happened that Galileo was familiar with a book published in 1543 by polish astronomer Nicholas Copernicus, the De Revolutionibus Orbium Coelestium (Revolution of the Heavenly Spheres.) This book proposed a Sun centered universe which did away with all the multitudes of epicycles that Ptolemy proposed. Epicycles were basically orbits within orbits (and sometimes on orbits several more times) needed to explain the motions of an Earth centered universe. Copernicus' book offered a much simpler explanation and this intrigued Galileo. And so, in 1609, Galileo built his first telescope.

One can only speculate on the thoughts which must have gone through Galileo's mind as he gazed at the night sky, but the one inescapable fact was that the observations made by Galileo supported a Sun centered universe

Probably Galileo's first observation, and the one which immediately must have astounded him was all the stars which appeared in his telescope but which could not be seen with the naked eye. This simple observation would have challenged the very Bible itself. In Genesis 1:17 the Bible states that the stars were in the sky to put light upon the Earth. Observations with a telescope refuted this concept and was why most people would not look through a telescope into the night sky.

Galileo turned his telescope to the Moon and noted that there were mountains on the Moon very similar to those on Earth. He looked at the Sun and saw sunspots. which would appear, and disappear over time Both of these observations proved that there were no “perfect and unchanging spheres.”

It must have seemed that everywhere he looked Galileo saw evidence for a Sun centered universe. While looking at the planets, Galileo saw the four moons that we call the Galilean Moons, Io, Ganymede, Europa and Callisto. Galileo was particularly interested in this “mini solar system.” Here was direct evidence that everything did not revolve around the Earth. Jupiter's moons also addressed the topic of a moving Earth. One of the arguments against a moving Earth was that as our planet moved through space we would lose our Moon. Here was direct evidence that this was not so.

And then Galileo turned his telescope on Venus. Astronomers had always noted that Venus always close to the Sun at sunrise and Sunset. The Ptolemaic model explained Venus' motions by putting it on a smaller epicycle and having the center of that epicycle always remaining on a straight line which joins the Earth and Sun. Using the Ptolemaic model, astronomers could explain waxing and waning crescents, but not the gibbous phases which Galileo observed.

While Galileo's observations advanced the science of astronomy, it very much displeased the church. These were the times of the Inquisition and it did not take long before the Italian astronomer was brought before them. Up until that time, the church had paid little attention to Copernicus' book but it was soon banned. Galileo was also punished, he was put under house arrest for the remainder of his life.

Galileo published his initial telescopic astronomical observations in March 1610 in a short treatise entitled Sidereus Nuncius (The Starry Messenger).And we bring the news to our readers in a publication of the same name.

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Kathy Miles, Author, and Chuck Peters, Systems Administrator
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