...you got me.

Yes it's fringey stuff but really interesting if he's right. Callisto exploding and pelting Earth with debris is one scary prospect he has seriously drawn attention to. If there's a chance he's done his sums right then it needs investigating.

He's not a Velikovsky since he actually knows his physics. But I'm not buying his line until there's some more serious evidence - for example his exploding Galilean moons theory is an overly dramatic way to get the thermal processing that has clearly shaped those moons. Personally I think a hot proto-Jove explains it, but if there's a chance he's correct then it can be usefully held in tension with mainstream ideas.

Adam