For the first time ever, physicists have set off a controlled nuclear fusion reaction that released more energy than what was put into the experiment.
The milestone laser shot took place on Dec. 5 at the U.S. Department of Energy’s National Ignition Facility at Lawrence Livermore National Laboratory in California. The fact that there was a net energy gain qualified the shot, in technical terms, as ignition. “Reaching ignition in a controlled fusion experiment is an achievement that has come after more than 60 years of global research, development, engineering and experimentation,” said Jill Hruby, under secretary of energy for nuclear security and the administrator of the National Nuclear Security Administration.
However, officials acknowledged that it’s still likely to be decades before commercial fusion power becomes a reality. They said the most immediate impact of the breakthrough will be felt in the field of national security and the stewardship of America’s nuclear weapons stockpile.
Galaxies don’t exist in a vacuum. Ok, maybe they do (mostly, since even interstellar space has some matter in it). But galaxies aren’t normally solitary objects. Multiple galaxies interacting gravitationally can form clusters. These clusters can interact with each other, forming superclusters. Our own galaxy is part of a group of galaxies called the Local Group. This Local Group is part of the Virgo Supercluster, which is in turn a part of a group of superclusters called the Laniakea Supercluster.
Mixed in with all of these galaxies is a lot of heat, with extremely high temperatures comparable to the core of our Sun, around 10 million Kelvin (27 million degrees Fahrenheit). This temperature is so hot that hydrogen atoms cannot exist, and instead of gas a plasma forms of protons and electrons. This is a problem for physicists though, who say it shouldn’t be that hot.
As Gianluca Gregori, a professor of physics at University of Oxford and one author of a new paper detailing an experiment to recreate the conditions inside a galaxy cluster, puts it: “The reason why the gas inside the galaxy cluster should have cooled down is simply due to the fact that the cluster has existed for a very long time (for a time which is comparable to the age of the Universe). So, if we assume thermal conduction works in the normal way, we would have expected the initial hot core to have dissipated its heat by now. But observations shows it has not.”