Why the U.S. Fusion Energy Discovery Really Is ‘Revolutionary’

There’s an old joke among scientists: Fusion power is just 50 years away—and always will be. However, that timeline might get just a bit smaller soon enough.

The U.S. Department of Energy is set to announce Tuesday that its scientists at the National Ignition Facility at Lawrence Livermore National Laboratory in California have achieved a ”breakthrough” in fusion energy—marking a massive milestone on the road to creating clean, sustainable power. Though the significance of this depends on who you speak with.

First, a quick and dirty physics lesson: Fusion energy...