Just when you thought the year was over in terms of major scientific breakthroughs, we get another one. And this one has such widespread implications that it has the potential to change our society in general.

Today it was announced that scientists at the Lawrence Livermore National Laboratory have successfully completed a fusion reaction that produced excess energy.

Let me begin with a quick explanation of the science involved. Back in 1905, Albert Einstein published the special theory of relativity, and among the revolutionary predictions it made, it predicted that mass could be converted into energy. This was demonstrated in spectacular form at the end of WWII, when refined uranium and plutonium isotopes were allowed to fission into lighter elements, and the energy that they released formed the first atomic bombs. In the decades that followed, this same technology was used to generate electricity in controlled fission reactions, but due to safety concerns the technology never really exploded (pun intentional).

An even better option for generating power is fusion reactors.

As one of my old chemistry professors liked to say, everything wants to be iron. Any atomic nucleus heavier than iron can be split into smaller nuclei, and in doing so will release energy. If these smaller pieces then trigger more reactions, we have a self-sustaining chain reaction and can continue harvesting energy until we take steps to slow down the reaction. And this is where the problem with fission reactors occurs - we have to actively damp them down to prevent them from producing too much energy too quickly. If the brakes fail, as has happened a few times throughout the late twentieth century, then the reactor will "melt down" and destroy everything in the vicinity.

However any atomic nucleus lighter than iron will do the opposite. They do not want to be split apart, but rather they want to be merged together. If two lighter nuclei can be fused together, the result will be one heavier nuclei and excess energy that can be removed and used elsewhere. (This is the mechanism that our own Sun and all other stars have been using for billions of years, and is the source of nearly all matter in the Universe). And a fusion reaction (usually) does not proceed spontaneously, so if something goes wrong then the reaction just stops automatically. There is no risk of melt down.

But it is this inherent safety feature that also creates the greatest obstacle to a functional fusion reactor. Lighter nuclei cannot get close enough to each other to fuse at normal temperatures and pressures. They may like to fuse when they are close together, but they will repel each other up to that point and so fusion reactions do not happen easily. In order to produce fusion reactions in the laboratory, scientists must use first add a lot of energy to the system to overcome this repulsion, and if they are successful then the nuclei will return that energy after the reaction, with a little extra energy added in from the reaction itself.

Except no reactor is completely efficient. The excess energy is tiny compared with the energy required to generate it, and so any inefficiencies will result in a net energy loss, and will render the reaction useless for energy production. The obstacle has plagued scientists for decades.

However the team at the Livermore Laboratory have finally overcome this problem. Using very precise equipment that was designed to be extremely efficient, they were able to remove more energy from the reactor than they have originally put in. For the first time in history, a fusion reactor has successfully generated energy.

To accomplish this, the team essentially created a spherical shell of high powered lasers that could push on the atoms from all sides. Instead of trying to increase the temperature and pressure of the entire chamber, they crushed the target material down to a tiny volume using these lasers, which caused the individual atoms and their nuclei to achieve the high energies necessary for fusion. The nuclei were being confined and accelerated by the laser beams until they collided, and fused into heavier nuclei. This method has been used before, but for the first time the scientists were able to extract enough energy from the reaction to keep the lasers operating, allowing them to fuse more nuclei and continue the fusion reactions, while also extracting additional energy from the reactor.

And this could have much bigger implications, not only for scientific research but for society in general. Fusion reactors can take ordinary substances like hydrogen (derived from sea water or other common sources) and produce energy plus hydrogen or lithium. (There is also a growing shortage of helium for use in medical imaging, so the waste products of a fusion reactor could benefit hospitals as well). In theory they can also be made small enough to be used on the next generation of spacecraft, allowing for us to travel further without our solar system and beyond. And if a fusion reactor fails, then the reaction stops and nothing more happens - they are completely safe. And perhaps most important in the current climate, fusion reactors produce energy without creating and greenhouse gasses or contributing to climate change.

For now the amount of energy produced is too small to be commercially viable, but now that it has been proven possible, it can be refined and improved upon. Within a decade or two we might have converted entirely to fusion reactors to produce our electricity, and perhaps even used them to colonize our solar system.

The fusion era has begun.