+- 1%? I doubt that you could find a majority of evolutionists who would agree that they could approximate the age of the earth within 1%. I think that is simply a number pulled out of thin air.
Tell you what, why don't you go actually learn the topic before spouting off more of what you "think" about it based on nothing more than your presumptions?
From The Age of the Earth, we find that yes, Virginia, many radiometric methods of dating the Earth have an accuracy in the range of 1%:
How Old Is The Earth, And How Do We Know?
he generally accepted age for the Earth and the rest of the solar system is about 4.55 billion years (plus or minus about 1%). This value is derived from several different lines of evidence.
Unfortunately, the age cannot be computed directly from material that is solely from the Earth. There is evidence that energy from the Earth's accumulation caused the surface to be molten. Further, the processes of erosion and crustal recycling have apparently destroyed all of the earliest surface.
The oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.
While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age.
The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites. This involves measurement of three isotopes of lead (Pb-206, Pb-207, and either Pb-208 or Pb-204). A plot is constructed of Pb-206/Pb-204 versus Pb-207/Pb-204.
If the solar system formed from a common pool of matter, which was uniformly distributed in terms of Pb isotope ratios, then the initial plots for all objects from that pool of matter would fall on a single point.
Over time, the amounts of Pb-206 and Pb-207 will change in some samples, as these isotopes are decay end-products of uranium decay (U-238 decays to Pb-206, and U-235 decays to Pb-207). This causes the data points to separate from each other. The higher the uranium-to-lead ratio of a rock, the more the Pb-206/Pb-204 and Pb-207/Pb-204 values will change with time.
If the source of the solar system was also uniformly distributed with respect to uranium isotope ratios, then the data points will always fall on a single line. And from the slope of the line we can compute the amount of time which has passed since the pool of matter became separated into individual objects. See the Isochron Dating FAQ or Faure (1986, chapter 18) for technical detail.
A young-Earther would object to all of the "assumptions" listed above. However, the test for these assumptions is the plot of the data itself. The actual underlying assumption is that, if those requirements have not been met, there is no reason for the data points to fall on a line.
The resulting plot has data points for each of five meteorites that contain varying levels of uranium, a single data point for all meteorites that do not, and one (solid circle) data point for modern terrestrial sediments. It looks like this:
Pb-Pb isochron of terrestrial and meteorite samples.
After Murthy and Patterson (1962) and York and Farquhar (1972) .
Scanned from Dalrymple (1986) with permission.Most of the other measurements for the age of the Earth rest upon calculating an age for the solar system by dating objects which are expected to have formed with the planets but are not geologically active (and therefore cannot erase evidence of their formation), such as meteorites. Below is a table of radiometric ages derived from groups of meteorites:
Type Number
DatedMethod Age (billions
of years)
Chondrites (CM, CV, H, L, LL, E) 13 Sm-Nd 4.21 +/- 0.76 Carbonaceous chondrites 4 Rb-Sr 4.37 +/- 0.34 Chondrites (undisturbed H, LL, E) 38 Rb-Sr 4.50 +/- 0.02 Chondrites (H, L, LL, E) 50 Rb-Sr 4.43 +/- 0.04 H Chondrites (undisturbed) 17 Rb-Sr 4.52 +/- 0.04 H Chondrites 15 Rb-Sr 4.59 +/- 0.06 L Chondrites (relatively undisturbed) 6 Rb-Sr 4.44 +/- 0.12 L Chondrites 5 Rb-Sr 4.38 +/- 0.12 LL Chondrites (undisturbed) 13 Rb-Sr 4.49 +/- 0.02 LL Chondrites 10 Rb-Sr 4.46 +/- 0.06 E Chondrites (undisturbed) 8 Rb-Sr 4.51 +/- 0.04 E Chondrites 8 Rb-Sr 4.44 +/- 0.13 Eucrites (polymict) 23 Rb-Sr 4.53 +/- 0.19 Eucrites 11 Rb-Sr 4.44 +/- 0.30 Eucrites 13 Lu-Hf 4.57 +/- 0.19 Diogenites 5 Rb-Sr 4.45 +/- 0.18 Iron (plus iron from St. Severin) 8 Re-Os 4.57 +/- 0.21
After Dalrymple (1991, p. 291); duplicate studies on identical meteorite types omitted. As shown in the table, there is excellent agreement on about 4.5 billion years, between several meteorites and by several different dating methods. Note that young-Earthers cannot accuse us of selective use of data -- the above table includes a significant fraction of all meteorites on which isotope dating has been attempted. According to Dalrymple (1991, p. 286) , less than 100 meteorites have been subjected to isotope dating, and of those about 70 yield ages with low analytical error.
Further, the oldest age determinations of individual meteorites generally give concordant ages by multiple radiometric means, or multiple tests across different samples. For example:
Meteorite Dated Method Age (billions
of years)
Allende whole rock Ar-Ar 4.52 +/- 0.02
whole rock Ar-Ar 4.53 +/- 0.02
whole rock Ar-Ar 4.48 +/- 0.02
whole rock Ar-Ar 4.55 +/- 0.03
whole rock Ar-Ar 4.55 +/- 0.03
whole rock Ar-Ar 4.57 +/- 0.03
whole rock Ar-Ar 4.50 +/- 0.02
whole rock Ar-Ar 4.56 +/- 0.05
Guarena whole rock Ar-Ar 4.44 +/- 0.06
13 samples Rb-Sr 4.46 +/- 0.08
Shaw whole rock Ar-Ar 4.43 +/- 0.06
whole rock Ar-Ar 4.40 +/- 0.06
whole rock Ar-Ar 4.29 +/- 0.06
Olivenza 18 samples Rb-Sr 4.53 +/- 0.16
whole rock Ar-Ar 4.49 +/- 0.06
Saint Severin 4 samples Sm-Nd 4.55 +/- 0.33
10 samples Rb-Sr 4.51 +/- 0.15
whole rock Ar-Ar 4.43 +/- 0.04
whole rock Ar-Ar 4.38 +/- 0.04
whole rock Ar-Ar 4.42 +/- 0.04
Indarch 9 samples Rb-Sr 4.46 +/- 0.08
12 samples Rb-Sr 4.39 +/- 0.04
Juvinas 5 samples Sm-Nd 4.56 +/- 0.08
5 samples Rb-Sr 4.50 +/- 0.07
Moama 3 samples Sm-Nd 4.46 +/- 0.03
4 samples Sm-Nd 4.52 +/- 0.05
Y-75011 9 samples Rb-Sr 4.50 +/- 0.05
7 samples Sm-Nd 4.52 +/- 0.16
5 samples Rb-Sr 4.46 +/- 0.06
4 samples Sm-Nd 4.52 +/- 0.33
Angra dos Reis 7 samples Sm-Nd 4.55 +/- 0.04
3 samples Sm-Nd 4.56 +/- 0.04
Mundrabrilla silicates Ar-Ar 4.50 +/- 0.06
silicates Ar-Ar 4.57 +/- 0.06
olivine Ar-Ar 4.54 +/- 0.04
plagioclase Ar-Ar 4.50 +/- 0.04
Weekeroo Station 4 samples Rb-Sr 4.39 +/- 0.07
silicates Ar-Ar 4.54 +/- 0.03
After Dalrymple (1991, p. 286); meteorites dated by only a single means omitted. Also note that the meteorite ages (both when dated mainly by Rb-Sr dating in groups, and by multiple means individually) are in exact agreement with the solar system "model lead age" produced earlier.
