The age of the Earth is measured by calculating how long it
would have taken for one element to decay into another, but
when we try to gauge deposition rates by looking at the direct
evidence, things appear to have happened much more quickly —
with rates increasing as one goes back in time.
All geological activity is driven by heat energy, and in the mantle
this heat comes from radioactivity. Were rates of radioactive
decay perhaps faster in the past? If so, then the timescale that
stretches the rock sequence and its fossils over 4.6 billion years
needs to be recalibrated.
A very different picture emerges. On the left is the conventional
view: evidence of microbes exists almost from the start, but life
fails to 'take off' until the last seventh of preserved Earth history.
Then a profusion of organisms appears as if out of nowhere.
On the right is a representation of the same sequence,
adjusted for time inflation. It begins with a global cataclysm
(its effects still visible on the Moon) that destroyed the original land. Thereafter new terrestrial and ocean crust formed
volcanically, and pre-existing organisms — programmed
with a huge potential for diversity — progressively recolonised
the Earth as conditions stabilised.