I found this summary [1] more illuminating. Also, the title is a bit misleading. The main achievement was that some scientists managed to produced an isotope o

I found this summary [1] more illuminating. Also, the title is a bit misleading. The main achievement was that some scientists managed to produced an isotope of sodium with 11 protons and 28 neutrons. If you head to wikipedia [2], you'll find that sodium is listed with at most 24 and 26 neutrons, with half lives of about 1.5 milliseconds and 60 nanoseconds. This makes sense, the further away you are from the stable isotope(s) (11 protons and 12 neutrons in the case of sodium), the more unstable the isotope. This experiment smashed calcium-48 against berillium atoms. Calcium-48 is a quasi-stable isotope of calcium: its half life is millions of times longer than the age of the universe. It has an unusually high number of neutrons. In the early part of the periodic table the stable isotopes have roughly an equal number of protons and neutrons. Ca-48 has 20 protons and 28 neutrons. Smashing Ca-48 against Be is a good way to generate isotopes with lots of neutrons. It took half a quintillion collisions to produce 9 sodium-39 nuclei. Which promptly decayed, obviously. They did not produce enough sodium-39 to be able to measure macro characteristics such as density, melting and boiling temperature, etc. Just enough to get an estimate of the half life. They generated some other neutron rich isotopes and estimated their half lives. How well did these half-lives align with the theoretical predictions? Here's the interesting part. Although we know the fundamental forces of nature, we can't model large nuclei starting from those forces. That type of modeling is called "ab initio" [3]. Or, rather, we can, but it's exceedingly challenging, very computationally intensive, and we need to take various theoretical shortcuts. As an alternative, people build empirical models, and fit various parameters to existing observations. The oldest such models were the liquid drop model of the nucleus [4] and the nuclear shell model [5], developed around WW2. Lots of refinements of the nuclear shell model were made. The way to tell which one is better is to make new observations and check which model made the better prediction. It turns out the model that best matched the newly observed Na-39 was a model published in 2020 [6]. Now, Na-39 was not the only isotope made by this experiment. Among others, they also produced Mg-38, which had a half-life shorter than any of the existing models can predict. This is good news. It means we have experimental evidence that will allow us to further improve our theoretical models. And these guys will not stop. They'll keep smashing various isotopes and generating new ones, and they'll make new observations. [1] https://physics.aps.org/articles/v15/177 https://physics.aps.org/articles/v15/177 [2] https://en.wikipedia.org/wiki/Table_of_nuclides https://en.wikipedia.org/wiki/Table_of_nuclides [3] https://en.wikipedia.org https://en.wikipedia.org /wiki/Ab_initio_methods_(nuclear_physics) [4] https://en.wikipedia.org/wiki/Semi-empirical_mass_formula https://en.wikipedia.org/wiki/Semi-empirical_mass_formula [5] https://en.wikipedia.org/wiki/Nuclear_shell_model https://en.wikipedia.org/wiki/Nuclear_shell_model [6] https://www.nature.com/articles/s41586-020-2848-x https://www.nature.com/articles/s41586-020-2848-x