As cities shut down their lights for Earth Hour at 8:30 to 9:30 pm local time tonight, you will have a brief respite from light pollution. Join the hour. Flip off your lights, head outside, and look up. Even if not everyone goes dark, you'll see something.

As a whole lot of you pointed out in the group discussion on dark skies, anyone who lives in a city usually only sees the sky during a power outage. Instead of dooming Manhattan to catastrophe, it's much more fun to stargaze when people cooperate to turn of the lights instead.

Photograph credit: Craig Ruttle/AP