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The Age of the Earth • "Everything which has come down to us from heathendom is wrapped in a thick fog; it belongs to a space of time we cannot measure. We know that it is older than Christendom, but whether by a couple of years or a couple of centuries, or even by more than a millenium, we can do no more than guess. " Rasmus Nyerup, (Danish antiquarian), 1802
The Earth is Old • By the mid 19th century geologist had established beyond a reasonable doubt, that the Earth was very old compared to earlier Christian thought. • Uniformitarianism. • Developed geological time scale using the principal of relative dating.
The question remained “How old is the earth exactly?” • Radiometric dating allows geologists to assign absolute ages to the relative dates established by the geologic time scale. Geological Time scale
Principles of Radometric dating • The number of decay events observed in a rock sample over time depends solely on how many radioactive atoms are present. • This is why we can calculate constant half lives. • Decay rates are not affected by temperature, moisture, or any other environmental factor. Conclusion: Radioactive isotopes function as natural clocks.
Principles of Radometric dating • Uses unstable isotopes of naturally occurring elements. • The isotopes decay into either different elements or different isotopes of the same element. • Each isotope decays at a particular and constant rate, measured in half-life. • One half-life is the amount of time it takes for 50% of the parent isotope present to decay into its daughter isotope. Measuring half-lives
The analysis of a rock shows that it contains 25% of the original parent radioisotpe. The half-life of this parent isotope is 1000 years. How old is the rock. A. 1000 years B. 2000 years C. 5000 years D. 1.2 million years old.
You are analyzing Moon rocks that contain small amounts of uranium-238 which decay into Pb-207 with a half-life of about 4.5 billion years. You determine that a rock from the lunar highlands contains 55% of the original uranium and the other 45% decayed intoPb-207. How old is the rock? • A = 3.88 Billion years • B= 5.18 Billion years • C = 4.20 Billion years
Calculating Radiometric dates ( ) Current amount of Isotope Log10 x Original amount of Isotope Time = ½ life ( ) Log10 1/2
Answer = A Answer = 3.88 Billion years
Concordancy Sr 87 / Sr86 2 4 6 8 Rb 87 / Sr 86
Concordancy Sr 87 / Sr86 2 4 6 8 Rb 87 / Sr 86
Is Radioactive Decay Valid? • Dating inner core of tree rings. • Bristlecone pine live up to 6,000 years. • Dating coral. • Ice cores • Differences between snow layers made in the summer and winter (date the dust found in the layers) • Dating varve layers. • Seasonal variation in sedimentary layers deposited underwater • Dating historical artifacts that the dates are already known. • A sample of acacia wood from the tomb of the pharoah Zoser was dated. Zoser lived during the 3rd Dynasty in Egypt (2700-2600 BC). • Ancient Papyri with known dates. (Dead sea scrolls)
Is Radioactive Decay Valid? • Compare radiocarbon results with the dates produced by other dating methods, • Agree with relative dating • Uranium/Thorium dating (dating coral etc) • Thermoluminescence (pottery, sediments), • Obsidian Hydration (obsidian), • Electron Spin Resonance, • Amino Acid Racemisation dating (eggshell, bones).
Is Radioactive Decay Valid? • An exponential decay is seen for short-lived isotopes with half-lives of only a few days. • For the decades they have been observed, the long-lived isotopes also follow an exponential decay. • The radioactive age of a rock layer is found using multiple types of radioactive isotopes with different decay rates.
Is Radioactive Decay Valid? • Travel in a time capsule to see if the physics of radiometric dating still apply.
The gamma ray frequencies and intensities produced by radioactive elements in supernova remnants change in the same predictable way as they do here on the Earth. • Example • supernova SN1987A that is 169,000 light years away in a satellite galaxy of the Milky Way. The predictions for the decay rates have turned out to be correct for all of the radioactive elements we have detected in that remnant. Since the SN1987A is 169,000 light years away, that tells us the decay rates were not different 169,000 years ago. We find similar results for supernova remnants even further away
The Appearance of Age • Both parent and daughter elements in each radioactive chain were created at the beginning, probably in “equilibrium” amounts. The amount of originally created radiogenic end-product in each chain is uncertain; it is likely however, that homologous amounts were created in all such minerals so that all such elements would, when created, give an “ appearance” of the same degree of maturity or of age.
The Appearance of Age • In 10,000 years since creation, the actual starlight that has had enough time to reach us comes form only a tiny proportion of our neighbors. This means that every event witnessed at a distance by Hubbell space telescope and other astronomical instruments, including the explosive disintegration of stars and the gravitational effects of black holes, is fictitious. None of these things happened-they were all constructed, artificially, in the trillions of photons assembled by the Creator to give his cosmos an appearance of age
The Character of God • Schemer? • A trickster? • A charlatan? • A God who intentionally plants misleading clues beneath our feet and in the heavens themselves. • This is all to lead astray anyone who uses their God given ability to reason
What effect does the views of Young Earth Creationist’s have on promoting Christian morality and ethics in society?
Reason and Faith • “It is a disgraceful and dangerous thing for an unbeliever to hear a Christian presumably giving the meaning of scripture and talking nonsense on these topics.” • “Many non-Christians are well versed in natural knowledge so they can detect vast ignorance in such a Christian and laugh him to scorn.” • St. Augustine 387 AD.
Reason and Faith I am not astonished that infidelity prevails to a great extent among the inhabitants of the earth, for the religious teachers of the people advance many ideas and notions for truth which are in opposition to and contradict facts demonstrated by science, and which are generally understood. (Brigham Young Journal of discourses 1856,)
Is it important to know the story of the creation? • If the Christian religion (indeed any religion) is to be believable and have intellectual integrity enough to command even the attention, let alone the assent, of thoughtful people in the beginning of the next millennium they must begin to acknowledge the ideas of Darwin and the truths of science. • Author Peacocke 1999
Why is it important to understand the validity of Radioisotope dating? • The Earth is very old. • Life on earth is at least 500 million years old. • Modern looking humans have been on the earth for at least 100,000 years. • The Americas have been continuously populated for over 10,000 years.
