Hello, my name is Walter Unglaub. And this is which one of Copernicus' theories was incorrect. Copernicus is most famously known for his heliocentric view of the universe. So, his heliocentric theory was published towards the end of his life in the year 1543. And it said that instead of the Earth being the center of the universe, the Sun was actually the center of the universe. And all the planet revolved around the Sun, including the Earth. So, there are several things or mainly just a couple things that are incorrect about his theory. One is the Sun is not the center of the universe. But rather it's only the center of the solar system. So, you have the Sun here and all the planets that revolve around it. And we see that the solar system is actually just one of many solar systems in our galaxy and it isn't in the center of the galaxy, let alone the rest of the universe. So, this is one thing that is slightly incorrect about his formulation. But he is correct in the sense that it is the center of the solar system. So all the planets do revolve around the Sun in our solar system. The second thing that he got incorrect is the fact that all these orbits are circular. Yes, you can approximate them with circles. But in fact these orbits are not circular but rather elliptical. So, orbits are not circular but elliptical. And this was demonstrated by Kepler more than 70 years later. Where Kepler came up with his three laws of planetary motion. And these laws were an improvement over the physical picture that Copernicus drew up in his heliocentric theory. My name is Walter Unglaub, and this is which one of Copernicus' theories was incorrect.