Recently, I was watching the rain and occasional lightning at Wimbledon (where, you may be surprised to learn, a few people occasionally play tennis this time of year).
The announcers mentioned that the complex will sport a Centre Court dome in 2009, so I began to wonder if lightning might slip through it and strike an innocuous object like the net, or scoreboard, or clock. Just something dramatic enough to scare the hell out of everyone.
Wouldn’t it be howlingly funny to see the unflappable Federer literally shit his pants at Centre Court!
Light is photons, and various frequencies of the electromagnetic spectrum (which includes everything from very long wavelength radio waves to very short wavelength xrays) will pass through various substances (x-rays will go through a piece of wood but “visible light” will not, for example).
Lightning is an electrical current - it’s the flow of electrons between clouds and earth (ground). Lightning could certainly travel through something transparent that is a good enough conductor, but it’s not because the material is transparent. I can see lightning causing damage to something opaque (the air around the bolt can be incredibly hot), but again that’s got nothing to do with the target being transparent or not.
Electricity has to do with the properties of the material; how friendly it is about passing electrons on through its atoms. Transparency has to do with how well it passes, or absorbs and re-emits photons. I didn’t study optics, so I can’t get more specific than that, but photons ≠ electrons.
Glass and plastics are both insulators, which means they don’t conduct electricity well. The dome will not pass lightning easily, and there’s a lot of air (also an insulator) between the top of the building and the court. If you want lightning strikes at center court, you’d probably have to provide a path for the current. A dangling copper cable hooked to a lightning rod at the apex of the dome ought to do the trick. Of course, people might start asking questions about what that’s doing there.
Lightning could easily burn through the dome but in order for lightning to strike there has to be a huge voltage difference between the cloud and the ground inside the dome. Voltage differences result from the separation of positive and negaiive charges. What happens in a thunder storm is that rain drops pick up negative charges (electrons) and carry them to the ground leaving behind the less mobile positive charges. The rain can’t bring the negative charges under the dome. However, it’s difficult to predict the distribution of charge inside the dome resulting from the excess nagative charge outside. Negaiive charges might pile up in the center of the dome repelled by all the negative charges outside the building. That would require mobile charges, like in damps soil, inside the dome. My WAG would be that the cloud and ground outside would equalize their charges with a lightning strike long before there would be enough concentrated charge inside to result in a lightning strike through the dome.
Transparent solids tend to be insulators. Something to do with electrons which are free enough to carry a current will also absorb photons (a bit vague I know, far too many summers have passed since I studied this sort of thing). Many insulators which look opaque actually would be transparent if made of a single crystal - in these solids it is the crystal boundaries which scatter light. Single metallic crystals are still opaque.
Conductors have electrons (or more rarely, some other sort of charged particle) in them which can move around freely. When an electromagnetic wave (that is to say, light) hits such a material, it causes the electrons to move, and in such a way that another wave is produced specularly (that is, it reflects like a mirror). Hence, conductors tend to be lustrous, which is why metals look the way they do.
Technically, it’s the “flow” of charge differential; the electrons themselves hardly move. That notwithstanding, Valgard’s (and others) explanation that lightning is not made of light is correct. Glass is a pretty good insulator, and in order to transmit a large amount of current through it would require a dielectric breakdown of the material, which in the case of glass would likely shatter the material from thermal shock.