The results of the poll "What is a galaxy?" - dark matter content is not the popular vote!

Through a popular vote, science-savvy members of the public have helped astronomers answer the question, ‘What is a galaxy?

1600 persons have voted on the question "What is a galaxy?" This question was posed by Prof. Dr. Duncan Forbes and Prof. Dr. Pavel Kroupa in a research paper published in 2011.

The majority of the voters (68 per cent) have specified a galaxy to be a gravitationally bound object which, in addition, needs to have a complex stellar population. That is, it must be filled with stars of different ages and chemical composition.

Surprising was that the majority did not vote for Dark Matter to be an important part of galaxies.

According to the popular definition of a galaxy, the most massive "star cluster" in our Milky Way galaxy, omega Centauri (pictured), would be a galaxy. This has indeed already been suggested by professional astronomers, because omega Centauri has a complex formation history.

More details can be found in the Swinburne University press release (see link below).