> He says the creation of element 117 “is at the absolute boundary of what is possible right now”.
I don’t fully understand why we can’t do a lot better than that.
Isotopes of superheavy elements are usually made by crashing together heavy nuclei at a precisely controlled energy. The extra energy gained from the collision is evaporated away by the loss of neutrons to form a nucleus with an energy very close to ground state. The time of flight and bending in a magnetic field of this nucleus, together with the energy of its decay products, tell the physicists exactly which isotope the nucleus is.
The first problem, and one that I don’t see an easy solution to, is that any isotope that happens to be stable can’t be observed. There are no decay products and so any such isotope can’t be identified by its decay products.
The second problem, and one that I can see an easy solution to, is that these new super-heavy elements are all on the neutron-poor side of the line of greatest stability. The heaviest element where the most stable isotope has already been found is element 108. The simple solution to this as I see it is to immerse the whole experiments in a bath of thermal neutrons. Even the superheavy elements that have so far been found have half lives measured in seconds, that’s huge. I suspect that it should be long enough for them to absorb low energy thermal neutrons from the surroundings and evolve into a more stable heavier isotope.