Earth Heroes: Meet these local nonprofit champions, dedicating their lives to protecting the air, land and water

Try to imagine what the night sky looked like the day your great-grandmother was born. (Or maybe your great-great-grandmother, if you’re young.) Thomas Edison hadn’t yet invented the light bulb, so artificial light was limited to candles and oil lanterns. The night sky looked exactly as it had for millions of years, studded with planets, stars, the bright arch of the Milky Way, and the occasional meteor, comet, or aurora display. But look up at night now, and what can you see?