Ten megajoules sounds like a lot, but a single kilo of TNT produces about 4 megajoules of energy. And the size of particles of dust and how often you’re likely to hit one in the interstellar medium is quite speculative.
> the size of particles of dust ... in the interstellar medium is quite speculative
Technically yes. I think there's a significant variety of sizes of dust or larger-than-dust particles in interstaller medium but I don't really have much to back that up.
> how often you’re likely to hit one in the interstellar medium is quite speculative.
Also technically yes. But unless you can map every single particle of dust, and their trajectories, I think the risk is absolutely real.
