A major 'fusion breakthrough' was just officially announced in the US. But what does it actually mean?

Artist's depiction of ions in the inertial confinement experiment. John Jett and Jake Long/LLNL

For the first time, scientists in the US have confirmed a fusion energy experiment achieved net gain. This means releasing more energy than it takes to initiate, demonstrating the physical basis for producing fusion energy in a controlled way.

This historic feat took place at Lawrence Livermore National Laboratory (LLNL) in California, using the National Ignition Facility experiment after decades of planning and research.