This website, authored by Ricky Leon Murphy of Astronomy Online, is a collection of references, images, and information for general astronomy. This work covers topics from the basics of science and observation through...

The Exploratorium in San Francisco has offered up this rather fun and interesting activity which gives interested parties the information to build their own scale model of the solar system. Visitors can start by filling...

This booklet describes the interstellar medium and the local bubble that is being studied by NASA-s CHIPS satellite. It contains review questions and problems for students, plus two activities to help to understand some...

This website contains basic information about Galaxy Clusters and their properties. Includes a brief explanation on how to apply the Virial Theorem to calculate a Cluster's Mass, and how the Theory of Dark Matter derives...

Astronomy notes is an educational resource for introductory astronomy classes for undergraduates. This section discusses the Hubble constant, Olbers' Paradox, Hubble's Law, the cosmological principle and the perfect...