Well, yes, Brian - that argument is very compelling, though it does require that the angels all dance in the same direction so as to avoid the obvious, infernal problem of the Kerr metric. And we all know where that can lead us.

Also, I'm not at all sure that such an angelic density would not, despite the authors' assurances to the contrary, generate a black hole of Dantean, verily, even biblical proportions, which would smite the Earth a terrible blow and perhaps even contribute to cherubogenic global warming.

Thanks, Brian!

Mike W.