The process that powers our sun was still a mystery about 100 years ago. Bit by bit, scientists have worked out that the fusion of hydrogen at a star’s core can generate enough power to keep it shining for billions of years. Now, armed with this knowledge, researchers around the world are trying to figure out if we can recreate that fusion process here on Earth. (And yes, trying to kickstart fusion—and then contain superheated plasmas that reach temperatures up to 100 million degrees Celsius—is just as hard as it sounds.) If scientists can pull it off, the payoff could be huge: A deep understanding of stellar physics could one day lead to a virtually unlimited supply of clean energy. To discover just how, Dr. Alok Patel hears from an astrophysicist and a fusion scientist.