How old is the Earth?
assumption that underlies all of the natural sciences is that
the processes of change we can observe today have always operated
in the same way throughout the history of the Earth.
This means that barely measurable geological and biological processes, like the uplift of mountains and the evolution of new animal species, have always been occurring vanishingly slowly.
From abundant evidence of profound changes that could only have occurred at such slow rates, geoscientists have inferred that the Earth must be very, very old.
But how is it possible to obtain a precise quantitative age for the Earth when nobody was around to mark its formation? These exercises will explore this question: