AN EXAMPLE

How can the 4,600 million years of Earth history be appreciated by humans who measure time in hours, days, weeks, months, years and generations? It is a massive amount of time!

This page is based on text and diagrams I used for my 1999 exhibition, Elementals, at the Museum of Modern Art, Wales. To try and show people how vast this timescale really is, I got the latest ages for beginnings and ends of the geological Periods into which this long history is divided. Then I plotted them in Excel against the 12-month calendar by which we organise our lives.

In such a plot, each month represents 4,600/12=383 million years. Each day would represent 4,600/365=12.6 million years. Consider then: relative to geological time, a human’s 80-year life expectancy equates to 0.55 seconds out of the 12-month calendar, and would not even be visible on this plot!

The graphic below is based on the old Excel plots. I've compressed it a lot for the web so sorry if it's a bit fuzzy! The outer ring is our 12-month year while the inner ring is the 4600 million years of Earth's history. The text is relevant particularly to Wales - note also that the plot is bilingual as it is a version of a much larger one which I created for a Forest Enterprise interpretation board.

Does this work for you? If anybody who reads this and has no prior geological knowledge finds it informative I'd be delighted to hear from them! It certainly made me think how chronologically insignificant Homo Sapiens actually is...

The text begins on New Year's day in the imaginary year...

January 1: about 4,600 million years ago. Earth condenses from the hot gases of the Solar Nebula...

January to early March: Hadean eon. The time of the “netherworld”. The new Planet Earth is largely molten and is constantly bombarded by asteroids. The oldest rocks so far known on Earth (around 3,800 million years old) are from the end of this time.

March to mid-June: Archaean eon. The ancient world. Earth now has a solid crust and oceans. Life starts to appear in the form of bacterial colonies during March (3,400 million years ago - oldest known fossils). But the atmosphere is poor in oxygen and is mainly ammonia, methane, hydrogen and other gases. The oldest known rocks in the UK were formed in May.

Mid-June to mid-November: Proterozoic eon. The time of earlier life, beginning 2,500 million years ago. Life continues to evolve slowly. The oxygen content of the atmosphere increases. By November, it is approaching today’s levels. The oldest known rocks in Wales were formed in early November.

Mid-November: Beginning of the Phanerozoic eon (the time of evident life), subdivided into three eras and eleven geological periods. The Palaeozoic Era (“age of older life”) begins with the start of the Cambrian Period, 543 million years ago. A huge explosion of evolution has taken place and the seas swarm with diverse life. England and Wales lie on one side of the ancient Iapetus Ocean, Scotland and Northern Ireland on the other.

December 3: The Carboniferous Period. The seas, rivers and lakes now swarm with fish and the first plants have appeared on land. They evolve and spread quickly. Soon, the coalfields of South Wales will form in tropical swamps lush with thick vegetation.

December 11: The end-Permian mass-extinctions decimate life on Earth. They bring to an end the Palaeozoic era. The Mesozoic era, meaning the “age of middle life”, commences with the start of the Triassic Period. NW Europe is a hot, dry desert.

December 14-December 26, 5.46pm: The Jurassic and Cretaceous Periods. The climate has improved and dinosaurs have now become well-established. The first small mammals are now thriving. But the tropical paradise comes to an end 65 million years ago with an asteroid impact and the extinction of the dinosaurs and many other life-forms.

December 26, 5.45pm-December 31, 8.29pm: The Cenozoic era, meaning the “age of recent life”, begins with the Tertiary Period. Under a warm climate, mammals thrive and diversify. They inlude the ancestors of horses, cattle, and, later on, apes.

December 31, 8.30pm: The climate suddenly cools and the Quaternary Period has begun. Several ice-ages affect NW Europe, in the final shaping of our landscape.

December 31, 11.37pm: Homo Sapiens - or Modern Man - appears.

December 31, 11.58.24: End of the last ice-age.

December 31, 11.59.47: The Romans invade Britain.

December 31, 11.59.54: The Norman conquest.

December 31, 11.59.58: The Industrial Revolution is now underway. In an instant, computers are in widespread use. Suddenly, the clock strikes midnight. Our trip through the past has ended. Welcome to the future....

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