Age of earth dating

Since 1955 the estimate for the age of the Earth has been based on the assumption that certain meteorite lead isotope ratios are equivalent to the primordial lead isotope ratios on Earth.In 1972 this assumption was shown to be highly questionable. Scientists think that the Earth is 4.54 billion years old.Coincidentally, this is the same age as the rest of the planets in the Solar System, as well as the Sun.All rocks and minerals contain long-lived radioactive elements that were incorporated into Earth when the Solar System formed.

As a result, rocks that record its earliest history have not been found and probably no longer exist.Some evidence is also presented to show that radiometric results that are in agreement with the accepted geological time scale are selectively published in preference to those results that are not in agreement.The geological time scale and an age for the Earth of 4.5 b.y.How do scientists know Earth is 4.54 billion years old?It’s actually difficult to tell from the surface of the planet alone, since plate tectonics constantly reshape its surface.At some point in the early history of Earth, a planetoid the size of Mars crashed into our planet.The resulting collision sent debris into orbit that eventually became the Moon.Thus, the geologic timescale and radiometric dating have been developed in an effort to determine the age of the earth.The older of the two dating methods, the geologic timescale, is actually a circular argument and is therefore considered by many scholars to be weak.Basically, this is how it works: earth's many rock layers contain billions of fossils.Certain fossils are unique to certain layers of rock.