That's where I was going. What do they mean by age? Although one could argue that the speed things travel through the universe alters their age, but from when

That's where I was going. What do they mean by age? Although one could argue that the speed things travel through the universe alters their age, but from when the Earth materialized, it shouldn't change much from particle to particle. If you're arguing for "oldest living thing" I do get it.