Engineers work at the National Ignition Facility in California's Lawrence Livermore Laboratory.

David Butow / Contributor

Scientists produced a nuclear fusion reaction that created a net energy gain, preliminary results suggest. The Department of Energy is expected to make an official announcement about the finding on Tuesday. Fusion energy advocates say it's a step forward in clean, cheap, and almost limitless electricity.

Scientists have reportedly made a "breakthrough" in their quest to...

Continue Reading How nuclear fusion works, and why it's a big deal for green energy that scientists made a 'breakthrough'