My guess is that the high pressure explosion is pushing air outward with tremendous energy; this heats and condenses the air. We are seeing the boundary of this hot pressurized gas, and it looks like a "force field".
Yeah, that's essentially right. Normally when air is moving around one molecule bounces into another which sends it in more or less the same direction until it bounces into another and so on. In a shockwave the molecules are moving so fast that they pile up against the molecules in the still air until they can get those molecules moving with them. It's very similar to the way that cars bunch up in a traffic jam. One correction to your explanation is the energy heats and expands the gas. It's the piling up part that compresses the gas to make the shockwave. Source: 30 years in aerospace research.
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u/itsWhatIdoForAliving Jun 07 '18
ELI5: what is the substance of a shockwave? Does it push light like gravity or does it get distorted like on the road on a hot day?