Flow battery advocates say their water-based technology needs a fraction of the metals used in lithium batteries and can store energy longer and without fire risk. But high costs could limit its role ...

Hawaiian petroglyphs dating back at least a half-millennium are visible on Oahu for the first time in years, thanks to ...

Thunder is one of nature’s most dramatic sounds, often accompanying the brilliant flash of lightning during a storm. But what causes this rumbling roar in the sky?