If you are paying attention, and on a trip of that magnitude I think you would be, you would notice the halo of gamma rays as the antimatter supercluster intera

If you are paying attention, and on a trip of that magnitude I think you would be, you would notice the halo of gamma rays as the antimatter supercluster interacts with normal matter around it. That said, the Larry Niven short story “Flatlander” is pretty funny. You should read it.