One characteristic of English that makes word games possible is the typical patterns of letter combinations. For instance, there are combinations like “st” and “pr” that you run into all the time. On the other hand, you hardly ever see “kf” or “jp” in combination. When you find a word that includes a rare combination, then, you really ought to check it out. And that brings us to “sferics.”
It’s the only English word that begins “sf…”, and it’s got to be one of only a few instances of “s” and “f” being put together in that order. There might not be any others, but it’s dangerous to rule anything out about English words. Anyway, “sferics” has to do with lightning. And contrary to what you might expect, it’s not an ancient word from some forgotten language; it’s not even a century old.
Lightning is constantly striking, just not in the same place. Well, technically, lightning does strike in the same place — but never mind about that. The point here is that there’s always lightning somewhere in the world. One of the effects of a lightning strike is a burst of radio waves. Because of their frequency (their radio frequency, not the rate of strikes), the radio signal propagates around the world, using the ionosphere as a wave guide. And that means you can detect lightning strikes from thousands of miles away.
Sferics sound like a series of pops or clicks, and they’re so constant it’s like the sound of frying bacon. Or, if you will, “static.” One of the first to describe the phenomenon was Heinrich Barkhausen, a German physicist. But while he mentioned it around 1918, it wasn’t until years later that the word “sferics” was coined to describe it.
The word was coined in the US, and it’s a shortened form (and alternate spelling) of “atmospherics”. Radio operators during WWII were well acquainted with it. There are more words in the jargon of atmospheric lightning, too: “tweeks” are higher-pitched signals produced by lightning (in this case, the lightning is so far away that the higher-frequency signal arrives first) and “whistlers” are descending tones — those come from north-south wave propagation along the magnetic field (I’m just repeating this; I don’t know what it means).
As to why this kind of white noise is called “static” — it seems to refer to static electricity (that is, a charged state that isn’t transmitted along a conductor, like current electricity is). And that’s what lightning is, after all. Just a static electric spark. A really big static electric spark.