it took several week to fully take over the planet four or five i think After Long Night of Solace, there is a clip that shows a HUGE fleet drop out of slipspace.glassingThey didn't. It took place over the course of a month.HAxThey didn't. it took many days. But to answer somewhat your question they 'glass' planets by concentrated beams of plasma down on the surface.the coventent took 6 days to conqure reachThey didn't, it took them about a monthThe Battle of Reach lasted about a month.They had a fleet of approximately 750 ships. Too many for the UNSC to handle, as the ships are faster and stronger and noble team was getting drunk in club erra and getting high off of grunt's methane tanks.