How would a nuclear explosion look in space?

Let's say, that a nuke goes off in space, any masses being far away. The familiar mushroom cloud and shock wave, are effects caused by the existence of air, or anything other than vacuum. So I figured, in space, most of the energy released in the reaction would probably be expressed the form of electromagnetic... show more Let's say, that a nuke goes off in space, any masses being far away.
The familiar mushroom cloud and shock wave, are effects caused by the existence of air, or anything other than vacuum. So I figured, in space, most of the energy released in the reaction would probably be expressed the form of electromagnetic radiation (and the alphas, and betas).... But, what I don't know is, whether that electromagnetic energy will be released as X-rays, and Gamma rays, and other highly energetic unpleasent photons, or would a noticable amount of it be visible light, so instesd of a little *poof* (and anything in range melting), there would be a grand flash.
Well? What do you say?
Update: About someof the answers I recieved... I'm not sure there would be visible light, bcause that will exist only if there's enough matter to heat up. That's why the sun gives out light, bcause of matter heatin up. wht I want to know, is whether visible light is emitted directly due to the reaction. and... show more About someof the answers I recieved... I'm not sure there would be visible light, bcause that will exist only if there's enough matter to heat up. That's why the sun gives out light, bcause of matter heatin up. wht I want to know, is whether visible light is emitted directly due to the reaction. and I'm talking about nuclear, not atomic explosions so, please consider the vast amounts of energy.
Update 2: About someof the answers I recieved... I'm not sure there would be visible light, bcause that will exist only if there's enough matter to heat up. That's why the sun gives out light, bcause of matter heating up. what I want to know, is whether visible light is emitted directly due to the reaction. and... show more About someof the answers I recieved... I'm not sure there would be visible light, bcause that will exist only if there's enough matter to heat up. That's why the sun gives out light, bcause of matter heating up. what I want to know, is whether visible light is emitted directly due to the reaction. and I'm talking about nuclear, not atomic explosions so, please consider the vast amounts of energy.
Update 3: And I know there wouldn't be shockwaves and mushroom clouds, I ruled that out in the question...
Update 4: Look, all I want to know is, whether visible light is emitted DIRECTLY from the nuclear reactions? can anyone give me a straight answer? (directly means:
Nucleus goes bananas=====>a visible photon is emitted)
Update 5: well, I guess, since most of the matter in the reaction stays... well... matter, then there would be enough matter around to heat up and glow. and besides, most of the energy gets out as invisible rays, but then again,1000000000000 is a one thousandth of 1000000000000000...
so a lot still does go out as light.
9 answers 9