Time, life and the Earth
Modern developments in the Earth sciences have revealed, for the first time, how our planet actually ‘works.’ For biologists, they have brought a fresh understanding of the interwoven histories of the physical and the living worlds. In turn, new biological discoveries show how early in Earth’s history life arose and how it was able to flourish even under the apparently hostile conditions of the young solar system. In particular the high ocean temperatures following meteor impacts would not have precluded the successful progress of so-called hyperthermophilic prokaryotic organisms.
The early problems which evolutionary biologists faced, when presented with estimates of the age of the Earth as a few tens of millions of years, have now been replaced by arguments concerning mechanisms underlying the variable rates and patterns of evolution.
Life and the Earth have reciprocally interacted over billions of years and repeatedly planetary processes have led to mass extinctions whose dramatic results can be seen in the fossil record even though the details of such events remain problematical. So far mass extinctions have resulted in increased opportunities for the survivors; the current human-induced extinction is unlikely to do so.
Figures & Tables
The Age of the Earth: From 4004 BC to AD 2002
The age of the Earth has long been a subject of great interest to scientists from many disciplines, particularly geologists, biologists, physicists and astronomers. This volume, The Age of the Earth: from 4004 BC to AD 2002, brings together contributors from these different subjects, along with historians, to produce a comprehensive review of how the Earth’s age has been perceived since ancient times. Touching on the works of eminent scholars from the seventeenth to nineteenth centuries, it describes how concepts of the Earth’s history changed as geology slowly separated itself from religious orthodoxy to emerge as a rigorous and self-contained science. Fossils soon became established as useful markers of relative age, while deductions made from geomorphological processes enabled the discussion of time in terms of years. By the end of the nineteenth century biologists and geologists were fiercely debating the issue with physicists who were unwilling to give them the time needed for evolution or uniformitarianism.
With the discovery of radioactivity, attempts to calculate the Earth’s age entered a new era, although these early pioneers in radiometric dating encountered many difficulties, both technical and intellectual, before the enormity of geological time was fully recognized. This effort affected both the theory and practice of geology. Geochronology was largely responsible for it maturing into a professional scientific discipline, as increasingly refined techniques measured not only the age of the rocks, but the rate of processes which now elucidate many aspects of the Earth’s evolution.
Even today the Earth’s chronology remains a contentious topic — particularly for those dating the oldest rocks — and it is implicated in debates surrounding our hominid ancestors, the origins and development of life, and the age of the universe.
The Age of the Earth: from 4004 bc to AD 2002 will be of particular interest to geologists, geochemists, and historians of science, as well as astronomers, archaeologists, biologists and the general reader with an interest in science.