Introduction to Astronomy:
For the people who don't know, astronomy is the part in science that has to do with celestial objects, space, and the physical universe as a whole.
Before the Renaissance, it was thought that the Sun and other planets orbited around the Earth. During the Renaissance however, the theory of the Sun being the celestial object that the planets, including Earth, orbits around was introduced. This was all thanks to the one and only Nicolaus Copernicus.
Who is Nicolaus Copernicus?
Known for being unknown in the first place, Polish astronomer Nicolaus Copernicus was the one who came up with the concept of a heliocentric solar system, which means that the sun is in the center of all celestial bodies and that those celestial bodies, including Earth, orbit around the sun. Back then, it was thought that our solar system was geocentric, meaning that the Earth was at the orbital center and the Sun and other planets revolved around the Earth. So when his fellow scholars heard about it, they didn't believe it, and when the Catholic church heard of Copernicus's model of a heliocentric solar system and his writings based on this theory, they didn't believe it either, which in today's modern terms would translate to something on the lines of, "lol no," and then promptly banned anyone from reading Copernicus's writings for about 3 centuries.
So yeah, that basically sums up his accomplishments.
Next up, let's talk about one of the biggest names in astronomy, you know the man, it's Galileo Galilei.
Pretty sure this isn't Galileo so this must be Nicolaus Copernicus.
Oh, you mean that old guy who discovered some moons and other stuff Galileo?
Yes, that guy.
Galileo did a lot of things didn't he?
Let's start with the Galilean Moons.
The 4 Galilean moons are Io, Europa, Ganymede, and Callisto, which are the 4 largest moons on Jupiter. Obviously they were discovered by Galileo in 1610 and were the first group of objects found to orbit another planet.
Fun-ish Fact:
Now, Jupiter is pretty far away isn't it? Well, of course one would require a telescope to view it, right?
Obviously.
Galileo Galilei didn't invent the telescope, but he did improve the telescope by a lot.
Originally called the spyglass, Galileo come about this device in 1609. He then used his mathematical and technical skills to ameliorate the spyglass, hence creating the telescope.
Galileo was the first man to look at the Moon through a telescope and make his first astronomy discovery, which is that the moon wasn't smooth, but mountainous and pitted. He also used thy telescope to observe Jupiter and it's moons as well at Saturn, since they didn't get to Uranus and beyond at that time. Along with that, Galileo observed Venus's phases and studied sunspots, which were located on the Sun, just saying.
There is also a link between Copernicus and Galileo, they both supported the theory of a heliocentric solar system, and just like Copernicus, the church still didn't agree with Galileo; this time however, they actually straight up arrested Galileo.
So that sums up the major parts of Renaissance Astronomy, basically if you thought that the Sun was in the middle of the solar system, you'll be punished by the church. What a time to be alive.
From Top to bottom: Io, Europa, Ganymede, and Callisto.
A picture of Galileo looking through his telescope