How old is the earth how do we know

These primordial space rocks, the leftovers from the formation of Earth and other planets, yield an age of about 4. The oldest known moon rocks, at about 4. Only a few uranium-rich, sand-sized grains of the hardy mineral zircon, some as old as 4. Nevertheless, uranium-bearing rocks, on every continent provide a detailed chronology of the early Earth Hazen et al.

The oldest Earth rocks, at about four billion years, point to the early origins of continents. Rocks from almost 3. Distinctive uranium-rich sedimentary formations and layered deposits of iron oxides from about 2. Indeed, every stage of Earth history has been dated with exquisite accuracy and precision thanks to radiometric techniques. Stromatolites, such as this 2. Radiometric methods provide an accurate approach to dating such ancient sediments.

Photo courtesy of Dominic Papineau. Overwhelming observational evidence confirms that Earth history is the story of the co-evolving geospheres and biospheres: Life has changed continuously over the course of Earth history. As the work of Eugenie Scott has so forcefully defended, Earth must be billions of years old Scott However, such a conclusion is at odds with the doctrine of many Christian fundamentalists, who believe in the literal Biblical chronology of a universe no more than about 10, years old.

How can science respond to such adamant claims? The testimony of the rocks is unambiguous: an enormous body of observational evidence points to the reality of deep time. Annual ice and rock layerings reveal a million years of Earth history.

Geologic rates of mountain building, erosion and plate tectonics demand hundreds of millions of years. Radiometric dating pushes the history back billions of years. And when these techniques overlap, their independent estimates of the timing of ancient events are internally consistent. And then, remarkably, he proceeds to describe how God created everything 10, years ago to look much older! But, no, according to the doctrine of created antiquity, the universe was created with light from those stars and galaxies already on its way to Earth.

We observe rocks with characteristic ancient ratios of radioactive and daughter isotopes. Presumably, the rocks are ancient. But no, those rocks were created with just the right mixtures of uranium, lead, potassium, and carbon to make them appear much older than they really are. Here, scientists are stymied. It is difficult to imagine any experiment or observation that could disprove the doctrine of created antiquity.

I refuse to accept the idea that any God would bestow such precious gifts as our senses and reason, seemingly to understand His creation, and then try to fool us.

Every scientific idea must be testable by observations or experiments that can be independently confirmed. In principle, it must be possible to imagine outcomes that would prove the proposition wrong. Without such independent confirmation, a hypothesis cannot be considered scientific. Created antiquity is not falsifiable.

Consequently, the teaching of young-Earth creationism, as well as any other doctrine based on a miraculous creation of life, has been repeatedly prohibited in public schools not because the doctrine was proved wrong, but because it simply is not science.

Aguillard , creationism is a religious belief that is inherently untestable by the techniques of science Working Group on Teaching Evolution Many lines of evidence point to the unfathomable antiquity of Earth. More than a dozen other techniques also provide reliable age determinations: fission-track dating based on gradual accumulation of radiation damage, thermochronology based on the slow diffusion of atoms through rocks, methods that rely on surface weathering rates or even on the slow growth of lichens.

These and other measures of deep time are independent yet yield the same unassailable results. Geologic data are complemented by insights from astrophysics see Krauss this issue and biology see Padian this issue. The lessons of the rocks, stars, and life are equally clear.

If you would choose to understand Earth then you must divorce yourself from the inconsequential temporal or spatial scale of a human life. We live on a single tiny world in a cosmos of a hundred billion galaxies, each with a hundred billion stars.

Similarly, we live day by day in a cosmos aged hundreds of billions of days. If you would seek for meaning and purpose in the cosmos, you will not find it in any privileged status in space or time. Rather, Earth and the heavens declare the glory of a cosmos bounded by natural laws that lead inevitably, inexorably to a universe that is learning to know itself.

Dalrymple GB. The age of the earth. Stanford: Stanford University Press; Google Scholar. Dickin AP. Radiogenic isotope geology. Cambridge: Cambridge University Press; Book Google Scholar.

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The sciences: An integrated approach. Hoboken: Wiley; Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4. Working Group on Teaching Evolution. Teaching about evolution and the nature of science. Download references. You can also search for this author in PubMed Google Scholar. Portions of this article have been adapted from Hazen and Trefil and Trefil and Hazen Reprints and Permissions.

Hazen, R. Evo Edu Outreach 3, — Download citation. Published : 26 May Issue Date : June Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search all BMC articles Search. Download PDF. Robert M. Abstract Earth scientists have devised many complementary and consistent techniques to estimate the ages of geologic events. Annual Rock Clocks Rocks reveal their ages of formation in several ways and provide Earth scientists with their most reliable clocks.

Full size image. However, the volcano rises approximately 10, meters above the ocean floor, so a rough calculation gives its age: Fig.

Radiometric Dating The physical process of radioactive decay has provided Earth scientists, anthropologists, and evolutionary biologists with their most important method for determining the absolute age of rocks and other materials Dalrymple ; Dickin Table 1 Common radioactive elements and their half-lives Full size table.

Created Antiquity Overwhelming observational evidence confirms that Earth history is the story of the co-evolving geospheres and biospheres: Life has changed continuously over the course of Earth history. Conclusions Many lines of evidence point to the unfathomable antiquity of Earth. References Dalrymple GB. Google Scholar Dickin AP. Book Google Scholar Fowler B. Google Scholar Download references. Hazen Authors Robert M. Hazen View author publications.

Additional information Portions of this article have been adapted from Hazen and Trefil and Trefil and Hazen About this article Cite this article Hazen, R. Copy to clipboard. Contact us Submission enquiries: Access here and click Contact Us General enquiries: info biomedcentral. The processes of plate tectonics mean that the Earth is constantly recycling its rock, breaking it down into magma in the interior before pumping it back up to the surface once more. But old rocks do exist, says Reich, and the oldest rock we know is a tiny piece of zircon found in western Australia.

The process of figuring out a rock's age often falls to the scientific techniques of radiometric dating , the most famous of which is radiocarbon dating. This process focuses on the ratio between the number of carbon and carbon isotopes in any once-living being: that ratio indicates how long it's been since that being was alive. But carbon is not the only element that can be dated— a whole host of others exist.

In uranium-lead dating, for instance, the radioactive decay of uranium into lead proceeds at a reliable rate. Based on the very old zircon rock from Australia we know that the Earth is at least 4. But it could certainly be older. Scientists tend to agree that our little planet is around 4.