The cold weather has settled in just in time for the official start of winter. The winter solstice is today, it marks the exact moment the earth starts to tilt back towards the sun. For those of us in the norhtern hemisphere, this means we'll begin to see longer hours of daylight. The Minneapolis Planetarium is marking the occasion with a special celebration tonight. Bob Bon-a-DUR is the Director of the planetarium. He says people have been celebrating the solstice for most of recorded history: Bob Bon-a-DUR is director of the planetarium. Tonight's celebration began at 5 o'clock. Shows will run every half hour until 8 p-m, with a fireworks display to mark the official moment of the solstice at 7:56.