Aristotle thought the earth had existed eternally. Roman poet Lucretius, intellectual heir to the Greek atomists, believed its formation must have been relatively recent, given that there were no records going back beyond the Trojan War. The Talmudic rabbis, Martin Luther and others used the biblical account to extrapolate back from known history and came up with rather similar estimates for when the earth came into being. Within decades observation began overtaking such thinking. In the s Nicolas Steno formulated our modern concepts of deposition of horizontal strata.
What is radiometric dating? Does it fit with the view of a young earth?
Many independent measurements have established that the Earth and the universe are billions of years old. Geologists have found annual layers in ice that are easily counted to multiple tens of thousands of years, and when combined with radio isotope dating, we find hundreds of thousands of years of ice layers. Using the known rate of change in radio-active elements radiometric dating , some Earth rocks have been shown to be billions of years old, while the oldest solar system rocks are dated at 4. Astronomers use the distance to galaxies and the speed of light to calculate that the light has been traveling for billions of years.
Radiometric Age Dating
Modern geologists , based on extensive and detailed scientific evidence, consider the age of the Earth to be around 4. This age represents a compromise between the oldest-known terrestrial minerals — small crystals of zircon from the Jack Hills of Western Australia — and astronomers ' and planetologists' determinations of the age of the solar system based in part on radiometric age dating of meteorite material and lunar samples. The radiometric age dating evidence from the zircons suggests that the Earth is at least 4.
When asked for your age, it's likely you won't slip with the exception of a recent birthday mistake. But for the sprawling sphere we call home, age is a much trickier matter. Before so-called radiometric dating, Earth's age was anybody's guess. Our planet was pegged at a youthful few thousand years old by Bible readers by counting all the "begats" since Adam as late as the end of the 19th century, with physicist Lord Kelvin providing another nascent estimate of million years. Kelvin defended this calculation throughout his life, even disputing Darwin's explanations of evolution as impossible in that time period.