There is time and then there is geological time. Like many concepts scientists find convenient, geological time has suffered from perceived conflicts with sacred myths. Scoffing at the myths is easy when they are the myths of powerless people. When the myths are based in the sacred texts of Islam (in parts of the world) or Christianity (in other parts of the world), scientific challenge has come at the risk of careers or even lives.
The scientific analysis of geological time conflicts with a literal reading of texts claimed to be messages from God by all three Abrahamic faiths. Protestant Christians, in particular, have calculated the beginning of time from the generations set out in that part of the Bible skeptics call “the begats.”
In the New Testament, the begats set out in the Old Testament serve the purpose of connecting Jesus to the House of David, a necessary lineage for the Messiah. In Genesis 5, the begats set out the exact life spans of many Jewish generational patriarchs. The best known would be Methuselah, who lived 969 years.
Skeptics go off on questions like causes of death and how Mrs. Cain and Mrs. Abel showed up, but the some of the faithful take the years of each of the patriarchs literally and add them together to get the age of Mother Earth, since Genesis purports to begin with the creation of the planet itself. These myths conflict with measurements that make up the work of geologists.
So who needs geologists?
Miners need geologists because valuable minerals are located in certain formations that appear in layers, and those layers are common everywhere on the planet in similar order.
The layers represent time, and newer layers demonstrate for biologists “faunal succession,” meaning that like fossils are found in particular layers, forming a basis for placing organic life on a timeline, another conflict with the religious view that all organic life was created at the same time, or at least the same week. Because radioactive materials decay at a known rate, it is possible to date even some layers of rock that contain no fossils, and the dates do not support the myths.
Radiometric dating claims Earth is over four and a half billion years old, far out of the time range that could work by adding up the begats. Geologists divide this profane notion of time into supereons, eons, eras, periods, epochs, and ages. Each division has characteristics that leave physical evidence on the land, and in modern times the terms of description are organized and coordinated by the International Commission on Stratigraphy so that all geologists can understand each other.
Followers of popular culture would recognize the Jurassic Period of the Mesozoic era, when dinosaurs dominated the planet and atmospheric CO2 was 4 or 5 times the level we consider a crisis today. Of course, dinosaurs had no reason to complain about sea levels or dangerous weather. The Jurassic ended 150 million years ago, give or take a few hundred thousand years.
Homo habilis, the first creature to share a genus with us, shows up in the fossil record between one and a half and two and half million years ago, making Handy Man at least a partial contemporary with the australopithecines, which most biologists take to be proto-humans. Australopithecines are divided into many species now that we were spared when I was an undergraduate but there is still no scientific consensus on the evolutionary path our ancestors traveled. We, Homo sapiens, show up in the Pleistocene epoch of the Quaternary period, the period we now inhabit. We have walked the earth for a relative eye blink in geological time.
Our epoch within the Quaternary period is the Holocene. However, geologists have known for some time that the rocks have begun to tell a new story and that new story is caused by H. sapiens, making the consensus descriptor “Anthropocene,” the epoch of humans.
Ironically, considering historical persecution of scientists by religious fanatics for taking human beings out the center of creation, the very idea of Anthropocene reintroduces humankind as acting rather than just acted upon. But many religious fanatics, over the same time period, have come to a new position that humans are not important enough to change the planet. Only God can do that.
Myth and measurement continue to be competing methods for understanding the age of the world. The stakes have been raised by measurements of anthropogenic climate change, because if humans have the power to degrade our environment then we also have the power to improve it.
Some of us would call it a duty.