Posted on 09/21/2003 11:20:34 PM PDT by bondserv
How Old Is the Earth? 06/05/2003
In the June 6 issue of Science, Stein B. Jacobsen of Harvard reviews current thinking about when the earth formed and how long it took. For the absolute age, he refers to a 4.567 billion year figure from a 2002 Science paper by Amelin et al, which analyzed meteorites for various lead isotopes and short-lived radionuclides (including 7Be with a half-life of 52 days). For relative figures, he compares tungsten and hafnium isotopic data to produce his timeline with the following caption:
The first new solid grains formed from the gas and dust cloud called the Solar Nebula some 4567 million years ago. Within 100,000 years, the first embryos of the terrestrial planets had formed. Some grew more rapidly than others, and within 10 million years, ~64% of Earth had formed; by that time, proto-Earth must have been the dominant planet at 1 astronomical unit (the distance between Earth and the Sun). Accretion was effectively complete at 30 million years, when a Mars-sized impactor led to the formation of the Moon.The 100,000 year figure reflects another article in the same issue, reporting on the recent annual meeting of the American Astronomical Society, in which author Robert Irion relays that growing numbers of astronomers are thinking the planets formed quickly by processes other than the traditional planetesimal accretion hypothesis. So despite Jacobsen’s air of confidence with his timeline, he concludes (emphasis added):
Precise measurements of W [tungsten] isotopes are among the most difficult measurements ever attempted by geo- and cosmochemists. As shown above, these studies are extremely worthwhile, even if some results turn out to be incorrect. It is important that several groups continue to perform such measurements and challenge each other’s results. A few precise and well-substantiated measurements are more informative than a large body of data with lower precision and accuracy.Not many would disagree with these sentiments. And yet earlier in his article, Jacobsen acknowledged that the dating game is still filled with surprises. Here are some excerpts (emphasis added):
So much rides on this date of 4.6 billion years. The entire biological evolution story and most of modern geology depend on it. It is quoted in the literature without question as if it came from a religious revelation. So we looked at the Amelin et al paper for data etched in stone, and found a house of cards. Though the data tables look impressive, over and over the authors build one assumption on another, judge some isotopic ratios to be more valid than others, and assume the very thing they are trying to prove – that the planets evolved out of a dust disk, which took a lot of time. How can they arrive at a number with four significant figures when nobody was there watching, and the methods depend on processes no one could ever know? If multiple supernovas were needed to seed the solar nebula, what effect did that have? What about Shu’s X-wind model, and proposed X-ray solar flares 100,000 times more powerful than those observed today, and multiple hypothesized episodes of melting and refreezing? They admit the meteorites were open systems, but how can they rule out processes unknown to us that could mess up the ratios? There is enough tweak space to concoct any story.
Jacobsen’s paper represents a common formula in evolutionary literature. A just-so story is told with all the authority of an eyewitness news reporter, and then the conclusion says, “more studies are needed.” This can be construed as, “We already know we are right, but we need more funding to find data that fit our preconceived notions.” This is a good time to recall Maier’s Law.
Nothing else in the solar system leads one to conclude such a huge date of 4.6 billion years. Here is a short list of phenomena, reported in previous headlines from papers in the secular scientific journals, that set upper limits much younger than that:This is just a partial list (details for most can be found by following the chain links on Solar System and Dating Methods). Each of these, if examined impartially without the prior belief that the solar system is billions of years old, would lead one to estimate much lower ages. To fit the 4.6 billion year timeline, all these observed phenomena have to be str-r-r-r-r-etched by many orders of magnitude. Why must that one figure of 4.6 billion years, arrived at by multiple levels of assumptions and tweaks, be the sacred cow to which all must bow?
- Mercury should be stone dead but has a global magnetic field.
- If Venus’ surface had a 4.6 billion year history, the first 90% has been obliterated.
- Earth’s magnetic field is decreasing at an alarming rate.
- The Grand Canyon could have been carved in just the last few thousand years.
- The moon and meteorites contain short-lived radionuclides.
- The moon should be stone dead, but shows evidence of activity today (transient lunar phenomena).
- Comets are burning up too fast (all the ones we know would be gone in 5000 years), and the hordes of spent bodies that should exist after 4 billion years cannot be found. Furthermore, the hypothetical Oort Cloud of comets could only contain 10% of earlier estimates.
- Meteorites are young, based on cosmic ray exposure.
- Some groups of asteroids have preferential spin orientations, that should have been randomized by now.
- Many asteroids are binary, but gravitational forces would tend to disrupt them in short order.
- Assumed cratering rates on Mars could be way off the mark, casting into doubt a widely relied on method of estimating ages.
- Large areas of Martian bedrock are exposed, but should have been buried deep in dust by now.
- Io has far more volcanic activity than can be explained by tidal heating.
- Io and Europa are losing a ton of their mass every second.
- Europa might have active geyser activity even today.
- Ganymede has a global magnetic field and evidence of recent resurfacing.
- Callisto shows signs of ongoing erosion, and has far fewer small craters than expected.
- Every planetary scientist agrees planetary rings are young, because they erode rapidly.
- Titan’s atmosphere is eroding quickly and cannot be billions of years old.
- Titan’s surface should be blanketed with half a mile of hydrocarbons by now, but large patches of bedrock ice are found.
- Enceladus, Tethys, Miranda, Ariel etc. are freezing cold, but show evidence of recent surface activity of unknown origin.
- Triton has a complex surface and active geysers, but inhabits a circular orbit (retrograde) without tidal stress.
- Triton and Pluto show evidence of a tenuous atmosphere.
- Neptune is the farthest large planet but has the strongest winds, and shows evidence of seasonal activity.
- Neptune’s rings have unexpected clumps of material.
- The orbit of Pluto’s large moon Charon is not tidally locked.
- Small moons are subject to short collisional lifetimes, yet each gas giant has many of them.
- The Poynting-Robertson effect would tend to sweep the solar system of dust quickly, but the solar system still has a lot of dust.
- Dust disks around other stars are seen to erode quickly.
So here we have a remarkable situation. At the early end of this 4.6 billion year timeline, everything happens rapidly; gas giants can form in just a few hundred or thousand years. At the near end, we see evidence of youth everywhere. There is a huge middle where astronomers need to keep short-lived phenomena going, like trying to drive around the world on a gallon of gas. Is there somebody out there, anybody, who will have the courage to question this bizarre figure of 4.6 billion years? If you do, be careful. It will be like tickling the bottom guy on a five-level human pyramid, with Charlie D. juggling on the top.
Take some time to get to know your enemy. We tend to be rather friendly, and open to rational discussion.
Depends. How old is George Clooney? You know it's his world, and we just live in it.
This figure is interesting as it comes up often with studies of isotopes. It assumes that there were equal amounts of, say U238and U235, created at the beginning (a reasonal assumption, but an assumption none the less) so the ratios of these isotopes still present and their known decay rates give a marker for their supposed date of creation.
All indications are that the earth is very old, certainly more than 10,000 years, and that still doesn't threaten the Biblical record or substantiate the theory of evolution.
The answer has been surmised enough. No human was there to observe its beginning who also is able to report with accuracy how much time has passed since. And even if he were, his report would have to be received with as much faith as anything that purports to be divine revelation.
The question assumes the earth has a beginning. In the end all of us make a leap of faith when we decide whether matter has a beginning or not, let alone the planet we inhabit. I've always wondered r.e. carbon dating whether scientists are measuring the age of a FORM or a SUBSTANCE.
You can talk to me all day about was life created or was it an accident, but the ages of the earth... that is the age of rocks is settled. Get over it.
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