The dream is the power of the sun. The sun is a dense ball of gas that is a fusion reactor.
A fusion power facility has succeeded in tipping the balance between energy input and output to achieve a net gain.
The result falls short of "ignition" - the "Holy Grail" of fusion science, which would generate more energy than the total amount needed to operate the reactor - but is still seen as a turning point.
At the National Ignition Facility (NIF) in California used 192 lasers to heat and compress a small pellet of fuel, a mixture of deuterium and tritium (DT), until its atoms began to collide and fuse.
By carefully tuning the laser pulses to maintain stability, the scientists produced an energy yield 10 times greater than any achieved before.
Crucially, the fusion energy obtained exceeded the amount of energy absorbed by the fuel to trigger the reaction.
This is not the same as generating more than the total energy needed to compress the fuel pellet, which is necessary for ignition.
if they get this right we could have almost limitless supplies of clean energy from special forms of hydrogen, the most abundant element in the universe.
Deuterium and tritium are two "heavy" isotopes, or atomic strains, of the gas.
From the journal Nature.