Lightning is spectacular, frightening, and dangerous. Everybody knows what lightning is, but nobody understands it. Indeed, the late atmospheric physicist Bernard Vonnegut (brother of novelist, Kurt) once quipped: What theoretician would have predicted lightning? Although the basic physics and structure of thunderstorms and lightning have been known for many decades (perhaps even centuries e.g., Ben Franklin), the details of the thunderstorm electrification and lightning discharge processes are only now being fully revealed due, in large part, to technological advances.

In this talk, I will first briefly summarize what we know about how thunderstorms become electrified and some of what we know about the physics of the lightning discharge. I will then describe and demonstrate some of the recent developments in lightning-observing instrumentation, including high-speed video at optical frequencies, three-dimensional lightning mapping at radio frequencies, and satellite-borne measurements of lightning at both optical and radio frequencies.

Though lightning is indeed dangerous, in some sense it is also quite useful. For example, the lightning flash rate is closely correlated with other convective processes (vertical motion, latent heat release, precipitation, and even severe weather). Lightning is thus useful in the sense that, compared with most other meteorological processes, lightning is easy to observe by a passive sensor because it radiates so strongly. I will end the talk with a description of how measurements of lightning can be (and have been) used as proxy measurements for other, harder to measure, quantities even on a global scale.