This former hacker saw the light-and now wants to collect all of it

BLUEMONT, Virginia—From an overlook in the foothills of the Blue Ridge Mountains, Dan Roelker gazed across the green splendor of the Shenandoah Valley. With the pleasant spring afternoon drawing toward evening, the Sun lazily crossed the sky, casting light all around. The pleasing environs had put Roelker, who was drinking rye whiskey procured from a local distillery called Catoctin Creek, in an expansive mood to talk about one of his favorite subjects, light. “If you can control light, you can control space,” he said. “So it’s basically a race for who is collecting the most light.” And Roelker, now 48…