1. Designing a Galaxy Classification Scheme

3. M51 (Modern View)

5. Taxonomy In order to understand what lies behind any physical phenomenon, you first need to classify it. The classification scheme is not an end in itself (unless you are collecting stamps). But it is a vital first step before it makes any sense to try and understand the underlying physics. “All science is either physics or stamp collecting” Ernest Rutherford

6. Classification Schemes Discrete: Useful for quantifying how common things are. Think about which physical properties are interesting

7. Classification Schemes Continuous: Useful for making quantitative measurements Useful for comparing different properties of objects in a multi-dimensional manner.

8. Height Weight

9. Designing a Galaxy Classification Scheme ~10 Minutes Work in teams to study galaxy images and come up with a classification scheme. Prepare a table-top “poster” illustrating your scheme. Prepare a minute presentation describing your scheme. ~40 Minutes ~10 Minutes Deliver your presentations to the rest of the group, at your table Introductory lecture