PX158 - J2 - types of galaxies
- there are three main types of galaxies
spiral galaxies
- contain a central region (bulge), and spiral 'arms'
- often contain young (blue) stars
- eg: milky way,
elliptical galaxies
- stars in an elliptical orbit around the centre
- extremely large
- contain old (red) stars
- potentially formed from the merger of spiral galaxies
irregular galaxies
- indistinct shape
- normally, small