Fire can be really fascinating stuff. Trying to freeze it in an image is tricky- it is not in the nature of fire to stay still!
I must have shot ~25 frames in that set, trying to get the flames to play just so around the moon. The shutter's cranked to 1/250 in an attempt to come close to freezing the flames. The aperture's stopped down to f/6.3 to yield enough depth of field that we can see the clouds and the moon. ISO 1600 balances the manual exposure calculation through a bit of trial and error; the Nikon D7000's usually excellent metering program can't quite figure out what it's looking at here.
Of course, slowing the shutter down can also yield interesting effects:
A fancy new high-ISO sensor isn't needed for this kind of thing; that last photo was shot on a vintage 2003 Olympus C750. The only real downside to that smaller, older sensor in this situation is its tendency to clip the highlights rather harshly.