Radiometric dating of sedimentary rocks is unreliable because
Samples in Western Australia run 3.4 billion to 3.6 billion years old.
Research groups in Australia found the oldest mineral grains on Earth.
In the early 20th century, scientists refined the process of radiometric dating.
Earlier research had shown that isotopes of some radioactive elements decay into other elements at a predictable rate.
There are multiple explanations for this uncomformity; in early 2019, one study suggested that a global ice age caused glaciers to grind into the rock, causing it to disintegrate.
Plate tectonics then threw the crushed rock back into the interior of the Earth, removing the old evidence and turning it into new rock.
Scientists interpret this range as the time it took for the solar system to evolve, a gradual event that took place over approximately 50 million years.
In an effort to further refine the age of Earth, scientists began to look outward.
The material that formed the solar system was a cloud of dust and gas that surrounded the young sun.
However, because plate tectonics constantly changes and revamps the crust, the first rocks have long since been recycled, melted down and reformed into new outcrops.
Scientists also must battle an issue called the Great Unconformity, which is where sedimentary layers of rock appear to be missing (at the Grand Canyon, for example, there's 1.2 billion years of rock that can't be found).The nearest body to Earth, the moon, doesn't experience the resurfacing processes that occur across Earth's landscape.