Newly created radioactive matter, as made in a particle accelerator, for example, will contain 100% of its originally created matter. None of it will have decayed into secondary forms yet. Radiometric dating of natural rock is done using that principle. New rock ("new" meaning just solidifying from molten form) will trap air from the atmosphere containing argon from the atmosphere. A certain (very constant) percent of argon atoms are a particular radioactive isotope, which decays at a very constant rate. The ratio of decay to parent product tells the age of the rock.
As you might guess, this system could be prone to error. It sometimes is. That is why, in actual practice, geologists do not rely on any one isotope for dating, but rather use several to see if a statistical distribution gives consistent results. If it does, one can conclude the system has some validity for that sample.
Radiometry is not the only method of dating rocks, either. There is the mapping of periodic magetic domain reversals. There are Milankovitch cycles leading to regular periodic sediment deposition. There are index fossils specific to particular layers of geological strata.
Mature galaxies where they definitely should not be...
An embellishment. Known galactic distribution is still consistent with a Big Bang model, only fine details about it are in debate.
The shift continues toward truth and away from speculative deception.
Exactly. Thanks to modern scientific research, we know with greater certainty than ever before the evolutionary pathways and mechanisms throughout the 3.5 billion or so year history of life on earth. 'Creation scientists' are the only ones trying to deceive people with websites and literature that preys on people's lack of scientific knowledge. Creationism might be an appealing option, but it's completely wrong.
La La La La, Mature galaxies where they shouldn't be means nothing. La La La La...