Institute of Astronomy

What is the bulgy centre of spiral galaxies like Andromeda?

Published on 09/05/2011 
Question: 

What is the yoke like bulgy centre of galaxy that we see in pictures like Andromeda, what is it made up of?

All spiral galaxies like Andromeda have a round bulge at the centre of the flat disc that contains the spiral arms. This 'bulge' is just a large ball of stars all tightly packed together; they are yellowy-red in colour as they are a lot older than the blue stars being formed in the spiral arms.

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Page last updated: 9 May 2011 at 08:53