It’s time for us talk about time again. Also time to review another science book: Earth’s Deep History by Martin J.S. Rudwick, 2014.

How old is the earth? It’s a question to which we now have an answer: 4.6 billion years. But for nearly all of human history people either did not think about how old the earth was (people have a long history of not thinking too much), or just held mistaken ideas about how old the earth was. Until quite recently, five or six thousand years was the standard, “scholarly” estimate for the age of the earth. Biblical reckonings and an assortment of folk legends and Creation stories sufficed for most people. Furthermore, the history of the earth began with the creation of people. Apparently, nothing much had happened until man and woman appeared on the scene. Well, perhaps there had been a brief “heroic” period, an age of titans and demi-gods. And supposedly, there had been a great Flood, etc., etc. But the vast extent of pre-human history remained unknown. As they say, the “story was hidden in the rocks”.

As Rudwick tells us in this excellent book, ancient fossils, dinosaur bones, and remains of the great Ice-Age megafauna – most of which were buried in the New World – remained undiscovered or just ignored for many years. It was only in the late 18th century and early 19th century that “prehistoric” fossils began to be uncovered. Similarly, geologists, such as Hutton in Scotland, Buffon and Cuvier in France, and many other European geologists, began to scientifically examine their local rock formations, and came to realize that these various cliffs, seashores, and river valleys etc had been formed over many, many years. According to Hutton’s Uniformitarianism doctrine, the earth was shaped by the same physical forces that we see operating today. “Actualism”or the principle that “what happens today happened back then too”, became a guiding principle in geology – and still is. The laws of physics are universal.

As “savants” in France, England, and other countries around the world learned to look at the morphology of fossils and to appreciate the processes of stratigraphy and the physical forces involved in the geological record, it soon became obvious that the earth was very, very, very ancient. Early scientists ventured bold estimates of the earth’s age. The physicist Lord Kelvin applied the recently-formulated laws of thermodynamics to calculated the time it would take for a molten earth to cool to present temperatures and came up with an estimate of a bit over 200 million years. As fossil discoveries accumulated and scientific information was exchanged within the small, but growing, 19th century, international scientific community, the absence of human fossils remained hard to explain.

Apparently, “natural history” didn’t start with Adam and Eve, and apparently the world was not static. Rather, the earth and life on it was constantly, albeit slowly, changing, or evolving. Mountains rose and fell, continents shifted. Interestingly, many of the early geologists were devout Christians, including Darwin and Lyell. Rudwick makes the point that in most countries, there was little conflict between religious and scientific thinkers. Indeed many of the early efforts in geology were guided and driven by efforts to confirm Biblical accounts such as Noah’s flood. But 19th century fossil discoveries revealed a previous era, or eras, of great sea monsters and extincted species – and rocks further down pointed to even vaster periods of time where there were no fossils at all.

Recent geological research – aided by modern, computerized, methods such as electron microscopy, isotope dating, seismography, as well as astronomical data – now provide a wonderfully rich picture of earth’s 4.6 billion year history – all explainable by the laws of physics operating over vast periods of time. Wow.

**************************

A Geo-Paleontological Poem

Hail the paleontologist

Picking at rocks

Searching for marvels in the chalky cliffs

Happy Lincoln’s Birthday Day, and Happy Charles Darwin’s Birthday Day!

Advertisements