Orion the hunter. Dark sky is becoming a thing of the past. Notice light pollution. It is perhaps the most significant pollution that we can actually do away with. We aren't going to stop burning fossil fuels anytime soon. We are not gong to stop using water or air soon either. But we can do away with extra light at night. Our ancestors did with out it, so can we. So start noticing all the extra night lights and then turn them off.