The old question “if a tree falls in a forest, and there’s nobody to hear it, did it really fall or even exist?” The question was often asked in psychology tests, as it gives a hint how the tester is thinking. There are two answers: in a subjective universe, the tree didn’t exist, and it didn’t fall. Objectively spoken: it obviously fell and existed. There exist probably a number of options between these extremes. Now, if you propose an object that has never ever been observed and will NEVER EVER be observable, I would suggest the question as to its existence is irrelevant as it is unanswerable, and questions that are unanswerable are, for most scientists (and rational human beings), uninteresting.