Designing a Galaxy Classification Scheme

M51 (Modern View)

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

Classification Schemes

Discrete:

• Useful for quantifying how common things are.

• Think about which physical properties are interesting

Classification Schemes

Continuous:

• Useful for making quantitative measurements

• Useful for comparing different properties of objects in a multi-dimensional manner.

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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