A question about the accuracy of dating the Earth and fossils.....

by EndofMysteries 16 Replies latest watchtower beliefs

• 

  jgnat

  It takes monumental force (nuclear-blast level) to change an element. As in....creation! This has been demonstrated over and over in the lab. There's no escaping the physics of it.

  P.S. This is high-school level education by the way, which is what I've got plus some supplementary reading.

  P.P.S. Before the fundamental structure of elements was worked out, alchemists had been working on formulas (with no success) to turn base elements in to gold. One element to another. For some reason, all their experiments failed.
• 

  EndofMysteries

  cofty - as I said in my first post " I would think these questions have already been addressed but can't find the answers." Thanks for that article, i'm checking it out.

  jgnat - high school level education in some parts of the USA means a teacher tells you to read a chapter in a book then take a test. The science courses never do any lab work nor do they really teach. Take that and + 10/15 years, you won't remember a thing.

  Anyway I'm back in college now, in the fall I'll probably be fullfilling the GE requirement for physical science, I may or may not chose physics for that.
• 

  jgnat

  http://www.scientificamerican.com/article/how-science-figured-out-the-age-of-the-earth/

  http://www.talkorigins.org/faqs/dalrymple/radiometric_dating.html

  Carbon-14 can't be used obviously, because it decays too quickly. The most used for the age range of your interest would be Rb-Sr, for having the "broadest range of applicability and are highly reliable when properly used".
• 

  jgnat

  They still call it chemistry but at the end of the day it's all physics!
• 

  Viviane

  Okay, so things up to 50k or 60k years may be covered from your answers.

  For carbon dating. For older dates that, there are other elements that have varying decay rates that can be used for millions or billions or year, uranium into lead or potassium into argon or rubidium into strontium, for instance. It's not required to know how much uranium was present to begin with because the ratio of the isotopes will tell us how much time has passed because te decay rate is constant.

  And they have gotten very good at detecting contamination that would throw off the dates and correcting for that.
• 

  kaik

  ---

  Carbon dating is only used in dating rather recent material going back couple thousand years. This is used in archeology, pollen in the sediments, etc. For the age of the rocks there are numerous methods of radiometric dating, from which the most common is potassium-argon, uranium-lead, and zircon. Each radiometric dating measure the conversion rate. The elements used in the dating are stable and will decay from isotop into stable element at the same rate (from uranium to lead for example it takes half-rate of 704 millions). Lead, argon, and zircon are extremely stable element. Argon is inert, noble gas, that does not react under normal condition (only in extreme lab setting it will create a compound, which is unstable).

  We have rather sensitive instruments that can measure the rate of the decay and the amount of isotops in material. There are about 15 common isotops in the nature that can be used for radiometric dating in geology:

  Isotope	Half-life (years)	Found in nature?
  In-115	4.41 x 10 14	yes
  Gd-152	1.08 x 10 14	yes
  Ba-130	7.00 x 10 13	yes
  Pt-190	6.50 x 10 11	yes
  Sm-147	1.06 x 10 11	yes
  La-138	1.02 x 10 11	yes
  Rb-87	4.97 x 10 10	yes
  Re-187	4.12 x 10 10	yes
  Lu-176	3.76 x 10 10	yes
  Th-232	1.40 x 10 10	yes
  U-238	4.47 x 10 9	yes
  K-40	1.25 x 10 9	yes
  U-235	7.04 x 10 8	yes
  Pu-244	8.00 x 10 7	yes
  Sm-146	6.80 x 10 7	yes

  Combination of various dating method, we can rather precisely identify a specific age. Zircon is the most used to determine the age of the earth:

  http://www.amnh.org/education/resources/rfl/web/essaybooks/earth/cs_zircon_chronolgy.html

  Besides the radiometric dating science uses additonal method determining age of the earth based on the magnetic field, paleomagnetism; from sediments, etc.

  Earth, Sun, and our planetary system can trace its life and origin to explosion of supernova that was huge enough to have producted various metals, gases, and elements within our solar system. We people are the descendant of supernova.
• 

  Nathan Natas

  EndfMysteries, I'd like to address two of your questions.

  The first is this business about radioactive decay. Jgnat said that elements are elements forever, and that is not strictly correct, as Jgnat's illustration shows, the radioactive isotope Carbon-14 turns into Nitrogen-14 and two sub-atomic particles when it breaks down. So, if you have an old sample of Calcium Carbonate - CaCO3 - and you do an analysis of it and find some Nitrogen (N) in there, the Nitrogen had to come from somewhere - from the decay of Carbon-14 into Nitrogen-14, which is a stable non-decaying form of Nitrogen.

  To this question, "It's also claimed the oldest rock/elements found on the Earth are 4.5 billion years old, so that is how old the Earth is. Does that mean that out of thin air the Earth appeared? What if those rocks and elements were floating in space from 4.5 billion years ago yet they clustered and gathered and formed the Earth only 1 billion or 1 million years ago? Is there more to the dating techique that specifies when they became part of the Earth?" I would offer:

  First (more than 13 BILLION years ago) there was the Big Bang, then energy began to become matter - individual atoms. The atoms bumped into each other, sometimes becoming compounds, sometimes becoming dust bunnies. Bunches and bunches of dust bunnies bumped into each other and the dust bunnies became large enough so that their combined mass gave them some significant gravity, and so the rate of collisions with other dust bunnis began to pick up speed. As the mass grew, so did the gravity of the mass. Now the dust bunnies were becoming rocks. As these clouds of rocky particles came crashing into each other, they got hot. VERY hot. The heat allowed a couple of things to happen - the bits of rock were now blobs of liquid rock, and because the mass was liquid, elements of different densities separated. If we had a very old rock in which some of the potassium had decayed into argon, the argon, being a gas, could now boil off of the hot molten blob.

  This had the effect of resetting the atomic decay clock. Once the molten blob cooled off, it containrd none of the argon it had before it melted. So when we measure the amount of argon in a rock that contains potassium, we know that when the rock was molten it had no argon in it, so all the argon we find must have accumulated after the molten blob cooled off. Thus we can calculate how long the rock has been solid. This is the age of the rock.

  Many of the 90 naturally occuring elements have radioactive isotopes, and these elements decay at different rates. This gives us ways of measuring different lengths of time.

  You said, "...I'm back in college now, in the fall I'll probably be fullfilling the GE requirement for physical science, I may or may not chose physics for that."

  I don't know what "fullfilling the GE requirement" means.

  Your intentions are good, but don't expect CHEM101 or PHY101 to answer all the questions you might ask. Become a science major (HARD WORK!) and study chemistry, physics, nuclear chemistry and LOTS of math.