Astronomy is a wonderfully visual discipline that is terribly difficult to actually visualize. But while our understanding may not encompass the distances, times, and sizes involved all at once, striving for two or even just one of the three at a time isn’t a bad goal.
I have always loved the scene in Carl Sagan’s Cosmos where the Big Dipper is projected backward and forward in time, and I’m amazed that I still can’t find a simple interactive online to do the same with whatever constellation I’d like. This program fixes that problem. Watch your favorite Western constellation or asterism evolve in 3D space over hundreds of thousands of years, or simply watch it as it would have looked (and will look) projected against the sky. Can you figure out which constellation is in the image below?
More of a visual than an interactive simulation, watch a planet and a star orbit their mutual center of mass.