The theory of plate tectonics has been in the mainstream of science thinking for the past 50 years. At such a milestone it is appropriate to see how far things have come and indeed what is still left to discover.

The theory of plate tectonics was born out of an understanding of our oceans. A map showing the age of oceanic lithosphere highlights the discontinuity between land and sea — the oldest rocks on our continents are billions of years old, yet the oldest part of our ocean is less than 200 million years old (Fig 1). The birth of…


The theory of plate tectonics has been in the mainstream of science thinking for the past 50 years. At such a milestone it is appropriate to see how far things have come and indeed what is still left to discover. Our planet is yet to reveal all it’s secrets… especially regarding the Earth deep below the surface.

Often the understanding about the Earth is shown in Fig 1, with the interior split into layers: the outer crust where we stand, the mantle below it extends down to the outer core (made of liquid iron) and then the inner core (made…

Philip Heron

Science communicator, theoretical geophysicist, documentary filmmaker

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