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Posted on 06/07/2010 5:29:41 PM PDT by decimon
The Earth and Moon were created as the result of a giant collision between two planets the size of Mars and Venus. Until now it was thought to have happened when the solar system was 30 million years old or approx. 4,537 million years ago. But new research from the Niels Bohr Institute shows that the Earth and Moon must have formed much later – perhaps up to 150 million years after the formation of the solar system. The research results have been published in the scientific journal, Earth and Planetary Science Letters.
"We have determined the ages of the Earth and the Moon using tungsten isotopes, which can reveal whether the iron cores and their stone surfaces have been mixed together during the collision", explains Tais W. Dahl, who did the research as his thesis project in geophysics at the Niels Bohr Institute at the University of Copenhagen in collaboration with professor David J. Stevenson from the California Institute of Technology (Caltech).
Turbulent collisions
The planets in the solar system were created by collisions between small dwarf planets orbiting the newborn sun. In the collisions the small planets melted together and formed larger and larger planets. The Earth and Moon are the result of a gigantic collision between two planets the size of Mars and Venus. The two planets collided at a time when both had a core of metal (iron) and a surrounding mantle of silicates (rock). But when did it happen and how did it happen? The collision took place in less than 24 hours and the temperature of the Earth was so high (7000º C), that both rock and metal must have melted in the turbulent collision. But were the stone mass and iron mass also mixed together?
Until recently it was believed that the rock and iron mixed completely during the planet formation and so the conclusion was that the Moon was formed when the solar system was 30 million years old or approximately 4,537 million years ago. But new research shows something completely different.
Dating with radioactive elements
The age of the Earth and Moon can be dated by examining the presence of certain elements in the Earth's mantle. Hafnium-182 is a radioactive substance, which decays and is converted into the isotope tungsten-182. The two elements have markedly different chemical properties and while the tungsten isotopes prefer to bond with metal, hafnium prefers to bond to silicates, i.e. rock.
It takes 50-60 million years for all hafnium to decay and be converted into tungsten, and during the Moon forming collision nearly all the metal sank into the Earth's core. But did all the tungsten go into the core?
"We have studied to what degree metal and rock mix together during the planet forming collisions. Using dynamic model calculations of the turbulent mixing of the liquid rock and iron masses we have found that tungsten isotopes from the Earth's early formation remain in the rocky mantle", explains Tais W. Dahl, Niels Bohr Institute at the University of Copenhagen.
The new studies imply that the moon forming collision occurred after all of the hafnium had decayed completely into tungsten.
"Our results show that metal core and rock are unable to emulsify in these collisions between planets that are greater than 10 kilometres in diameter and therefore that most of the Earth's iron core (80-99 %) did not remove tungsten from the rocky material in the mantle during formation", explains Tais W. Dahl.
The result of the research means that the Earth and the Moon must have been formed much later than previously thought – that is to say not 30 million years after the formation of the solar system 4,567 million years ago but perhaps up to 150 million years after the formation of the solar system.
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Contact: Tais W. Dahl, PhD. geochemistry, Cand. Scient. geophysics, Niels Bohr Institute, University of Copenhagen. Currently at Harvard University: 00 1 617-817-5506, tdahl@fas.harvard.edu
Happy Birthday to us.
I cannot, because they haven't, which you know to be impossible.
You cleverly put forth this argument knowing that no experimentation on that scale is possible. Even though the laws of physics the theory is based on have been amply demonstated and measured in the laboratory on scales the we can manage, you tacitly assert that such observations and measurements cannot be scaled and extrapolated to objects that exist outside the laboratory. It is as if everything exists in a vacuum and there is no reason or basis to assume any consistency in the Universe.
You should get a Nobel Prize for that.
Oh, not THAT canard again. Please post the link to the peer-reviewed journal article that states your SNOPES-worthy assertion.
He was too busy giving us The Partridge Family and Hanson.
What if it took longer than 100 million years between the supernova(e) that created the radio-hafnium and the formation of the solar cloud proto-planets? hummmm?
Folks, valkyry1 has an obsession with me. He/she/it follows me around and then pretends to be interested in the subject matter.
I don't blame he/she/it -- I am pretty interesting.
Here’s another for you. Definition of Fact:
“Something demonstrated to exist or known to have existed.”
Still observable. Only a moron would continue to argue with a clearly and repeatedly defined word, and pretend it is something else, so please don’t. SCIENCE MUST BE OBSERVABLE, AND MEASURABLE, PERIOD.
Lets hope they are more reliable than their "climate models".
I'm a little skeptical of the "science" behind this partcular claim. I'm not aware of very much physical evidence that survives the period in question. Also, the article almost seems to state the the formation of the solar system was a small amount of time - almost like it was a fixed point in time, rather than a continuous process that probably took quite a long time to "complete" itself. That may just be the inaccuracies you find any time a reporter gets hold of a story to mangle. Personally, I would kind of imagbine that when you are speaking of the geologic timescales that would be needed to form a solar system, a 30-150 million year range is not very large in the overall scheme of things.
Is it such a stretch to accept the precepts of a book of Moral and cultural Direction without demanding scientific rationalization of every presumption and claim?
We can make believe any timeline we wish, because it’s not science, it’s conjecture.
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The half life of Hafnium-182 decaying into Tantalum-182 is 9 million years (Tantalum-182 to Tungsten-182 is only 114 days). In 54 million years there would be 6 half lives, leaving 1.56% of the original hafnium atoms. That's not a lot, but no one would say that "all" had decayed into tungsten.
As I previously said, I don’t believe that the Earth is only 6,000 years old. I don’t care what you believe, and what faith you subscribe to. This still isn’t science, and hence is just conjecture.
Not much point in following this further. A statement like that stands alone.
Abandoning thread since it has descended into utter insanity.
“I’m not aware of very much physical evidence that survives the period in question”
Hooray! Someone else who knows what science is!
Is it old enough to drink yet?
That much is obvious. Thank you for pointing it out.
Thanks. Next I’ll tackle the climate models and why they are not science either. Because the “theories” behind them, cannot work because there are more variables that man/scientists can account for. Hence, figures of unobservable things like the earth’s age are ridiculous. And NOT science.
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