That world is sealed inside a light tomb.” “A light tomb?” “It’s a reduced-lightspeed black hole produced by the trails of lightspeed ships. Something happened on World III that caused them to think that their coordinates had been exposed. They had no choice but to turn their world into such a black hole.” “We call such a place a black domain.” “Ah, good name. As a matter of fact, the people of World III initially called it a light curtain, but outsiders referred to it as a light tomb.”
