A model of a solar system first and foremost with a small projector built in, the Science Can Solar System Planetary Projector is a great educational tool for kids.

The biggest issue, however, is that the outer solar system just hasn't been observed for long enough. For example, object 2017 OF201 has an orbital period of about 24,000 years.

The way people think of the Solar System has changed many times throughout history. Before the development of the telescope, these ideas were based on what could be seen with the naked eye. This ...