How did they know at any given point that it was still there? Wouldn’t they have to interact with it to be sure, causing an explosion and annihilating it? The explosion would be incredibly small with just one particle. Is the lack of explosion their only evidence that they had contained it? I’m stumped as to what it actually means to have one particle like this. How can you even know what temperature it is without interacting with it? And how do you interact with it without destroying it?