Can anyone come up with a good comparison for this? A sphere the size of Mercury's orbit is an order too large (~ 1.4e36L according to Wolfram Alpha).

Edit: Of course Mercury's orbit isn't spherical, but we're talking ballpark here :P

I like the idea of using Mercury's orbit as a comparison. Some more fodder:

Just over 13,583,569.4 times the volume of the Sun. [2]

[2] http://www.smartconversion.com/otherInfo/Volume_of_planets_a...