Young Earth Creation science says the world is only 6000 years old.
The physical evidence present and the observed physics of the radiometric decay of long half-life radioisotopes says that’s not possible.
Does it really?
Are you aware of the unverifiable assumptions necessary to come to the conclusion that you just stated?
assumption of the initial state of the measured sample (initial amounts of parent/daughter elements present),
assumption of constant rate of decay (shown recently to be not constant),
assumption of non-contamination and no leaching of elements from other sources.
Different elemental decay measurements on the same sample can give wildly varying "ages" - do you know how they determine which one is right? By the assumed age of the fossils "near" the sample. Circular reasoning.
Are you aware that "new" rocks from Mt St Helens dated to "millions of years" when they were only a few months old? (The "clock" is assumed to start ticking when the rock cools from molten state, on new and "old" rocks.)
Of course, even though this method doesn't work on known age rocks, we have to assume that it works on rocks of unknown age.