It's peak summer on Minnesota's Gull Lake Chain. Boats are buzzing, jet skis slicing and loons are calling. "So it sounds like a territorial challenge that's starting," said Sheila Johnston, listening ...

MINNESOTA, USA — "Imagine now, a clear summer evening in the north woods. Above you, the bands of the Milky Way framed by the dark spindly boughs of spruce and fir. And cutting though the stillness ...