The lab's national ignition facility is the size of three football fields; all to focus a giant wallop of energy on one tiny spot.
"We're basically recreating a small piece of the sun inside, inside the laboratory," physicist Pravesh Patel said. "Which has never been done before."
The sun creates energy through nuclear fusion -- squeezing atoms together until they merge into one, giving off massive heat.
Science fiction fans probably know that fusion powers the warp drive on the Starship Enterprise.
In reality, the inside is dozens of precision lenses focusing laser light so powerful it squeezes a tiny pellet of hydrogen fuel until the atoms start to combine.
And now, by carefully adjusting the pattern of that giant pulse of light, scientists have gotten the fuel to start heating itself -- you could call it smoldering, the smoke that comes before fire.
The achievement is a major step forward toward the ultimate goal of the national ignition facility, which is "ignition" -- the nuclear equivalent of getting the fuel to catch fire so it burns on its own.
Right now, the fuel's giving off about twice the energy they put into it, but only a tiny bit at the center is actually reacting.
Ignition -- the so-called Holy Grail -- is a chain reaction.
"That chain reaction will run away and we'll be able to convert most of that fuel into fusion energy," Patel said.
Energy equal to pounds of burning coal, from a pellet the size of one pixel on your TV.
"It would be an incredible long term solution to our energy needs," Patel said.