Orrery is a noun that refers to a model representing the solar system. 

Our word of the day got its name from a historical figure known as the Fourth Earl of Orrery for whom a model of the solar system was made in the early 18th century. The model and the name for it are still with us today. Here’s an example of orrery in use:

As a teenager, I wanted to make an orrery for the annual school science fair. But because I was a little lazy in gathering all the necessary equipment, I couldn’t make a model of the whole solar system. I had to settle for a light bulb to represent the sun.