A 13-year-old listener wrote in asking if the inverted yield curve means that a recession is on the way. Today on the show, we try to answer him.
You need helium to launch rockets into space. It's also essential for MRI machines and cellphones. But the world is running short on helium. So we're going looking for more.
Solar energy used to be a fantasy. Then it arrived, but was too expensive for most people to afford. Now it's cheap. Here's how it happened.