If you've centred your object, running Radial Blur on the default settings will smooth the edges. This is a play around tut' ... as in play around and try different blend modes etc as the results vary.
Some I played around with:
As I say, these are all play arounds ... I remember there's some Condition Hue/ Saturation in the coloured one. The shiney one, I made the circles ... duplicated the layer ... set blend mode to Negation ... then used Darken from the Adjustments menu on the layer below to get the bright silverish look.
Enjoy ... and remember to think outside of the box :wink: