Dendrochronology is a method of dating based on annual tree growth patterns called tree rings.
Tree rings are the result of changes in the tree's growth speed over the year, because trees (in normal conditions in temperate regions) grow faster in the summer and slower in the winter.
This article collects evidences that place a lower limit on the age of the Universe beyond the 6,000 to 10,000 years asserted by most Young Earth creationists (YECs) and the literalist Ussher chronology.
All of this evidence supports deep time: the idea, considered credible by scientists since the early 1800s, that the Earth (and the Universe) is millions or billions of years old.
Widmanstätten patterns are crystals composed of nickel and iron that are found in some meteorites.The thickness of tree rings varies with the local seasonal weather, so a sequence of thick ring, thin ring, thin ring, thick ring, thick ring, thick ring, thin ring, thick ring shared by two trees is strong evidence that the corresponding rings formed at the same time.Each individual tree only covers the span of time it was alive and growing, but as these spans overlap it is possible to match up overlapping sections and work backwards.There are three standard creationist responses: First, creationists assert that current rates (Y) are different than past rates.It is possible that these rates changed — but under uniformitarianism, which is necessary for science to function, we must assume that rates did not change unless there is evidence for this change.