system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the scientific 'gain' to be had from mashing elements together to create new elements that have half lives measured in miliseconds? Other than filling up the periodic table and giving them fancy names how does science benefit?
gpt
We can't really observe why a nucleus stays together or how that works. You can't really watch something not do something. What we can do, however, is make many kinds of nuclei that don't stay together and pay attention to what happens. Then, we look at all of those different behaviors and make really solid inferences about how stable nuclei work and how the particles interact with each other and what role they and various forces play in that mechanism by seeing what happens when they *don't*. 

Think of it like using footage of the Tacoma Narrows Bridge collapse to understand engineering principles that inform us why other bridges don't collapse.

Additionally, as a bonus, the engineering that goes into devising the experiments to develop the theory side of things sometimes leads to technological advances.

Edit to add: there's a running gag in Calvin and Hobbes, where whenever Calvin asks his dad anything about how the world works, the answer he gets is comedically ridiculous. In one strip, Calvin asks his dad how they know the weight limit for bridges. Calvin's dad explains that they build the bridge, and then drive bigger and bigger trucks over it until it collapses, then rebuild the bridge and weigh the last truck to make it over successfully. This is actually pretty close to what we're talking about here, except there are so many more dimensions than weight and there are things we can learn from a truck that was three times too heavy for the bridge that we couldn't learn from a truck that was only two times too heavy.