It's one of science's ultimate goals, and perhaps the only thing that could prevent humanity's ultimate depletion of the Earth's resources -- the ability to produce more energy than is used to make it. Now, a new nuclear breakthrough has brought that feat even closer to becoming a reality.
Continuing on from an earlier breakthrough last year, US researchers at the National Ignition Facility at the Lawrence Livermore National Laboratory in California have managed to generate more energy from a string of fusion reactions than was put into the nuclear fuel used within them. While it still hasn't reached a stage where scientists have been able to create more energy than the entire experiment consumes, it's a significant step forward. (It's worth noting that last year, researchers managed to produce more energy through the fusion reaction than the amount of energy being absorbed by the fuel, rather than put into the fuel.)
But it's a complicated, painstaking process to even achieve this small gain. Attempting to replicate conditions at the heart of the Sun, the researchers fire powerful lasers at a tiny amount of fuel coating the inside of a 2mm-wide spherical capsule made of gold. Once the laser light enters the sphere, the gold begins to emit x-rays, heating the pellet dramatically and making it implode. The fuel coating (containing hydrogen isotopes called tritium and deuterium) partially fuses. However, no more than 17 kilojoules of energy is released, despite the same amount of energy as two exploding sticks of dynamite being unleashed by the lasers.
A small victory then, but still some way off from solving the planet's energy woes. While the research will tremendously aid formative plans to build a fusion reactor, for now the project's main goal remains attempting to understand how the US's nuclear stockpile is ageing, and what dangers that may pose. [Guardian]