Today is the 543rd birthday of Nicolaus Copernicus, the man who formulated the heliocentric model of the universe. His book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published shortly before his death in 1543, was a major contributor to the Scientific Revolution. It is also an excuse for me to post some vaguely astronomical videos today.
First, a gif which illustrates both the relative orbits of Earth and Venus and, I think, the beauty of mathematics.
Next, Celestial Dynamics, an animation based on illustrations from old science textbooks.
And, finally, a video of the stars as seen from the International Space Station.
I hope everyone has clear skies and time to look at the stars this weekend.