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
Preach on the “I don’t knows” in academia. Been doing that since grad school.
The carbon dating was a post in response to something that someone said earlier.
After reflecting upon what others have said (Most notably AussieJoe), I’ve decided that you have a point in saying, “Sounds like somebody likes to throw the model baby out with the science bathwater,” and admit, I should give credit where credit is due.
While I still would have a hard time swallowing any type of timeline presented, I’m willing to give these “scientists” credit. They have furthered our understanding, and that is noteworthy, even if, for now, it is more applicable to theoretical physics (in my view, conjecture), than it is to quantifiable, observable, reality. But I guess that it is such leaps of faith, which get us from point “A” to point “C”, without knowing the particulars of point “B” until it’s hindsight.
I still don’t belive anyone knows the color of a dinosaur. :)
This is intrinsically untrue in quantum mechanics, and (in a different way) practically untrue of chaotic systems.
And of course, by Murphy's Law, under the most rigorously controlled conditions of temperature, pressure, and humidity, the organism will do as it damn well pleases ;-)
Cheers!
Thank you for your intellectual honesty. (I totally agree with you re. the color of a dinosaur ;^) )
Agree with you on the dinosaur color. Definitely conjecture. My boys and I have had that conversation....”Daddy, How do scientists know the color of dinosaur skin?????”
The “I don’t knows” are one of toughest things my students have trouble understanding about science. That and field theory. ;)
Agree with you on the dinosaur color. Definitely conjecture. My boys and I have had that conversation....”Daddy, How do scientists know the color of dinosaur skin?????”
The “I don’t knows” are one of toughest things my students have trouble understanding about science. That and field theory. ;)
Ah, what’s a measly 150 million years when you’re talking 4.5 billion or so years ago? :D
How about 6000 years ago? That is the biblical position.
Paging Mr. Sitchin, Mr. Zecharia Sirchin. Please pick up the white courtesy phone.
Write 100 times on the blackboard:
Empirical knowledge: GOOD
Wild, drug-induced speculation by the liberal
assitant professors of your youth: BAD!!!!
Very possible.
Except present day human mitrochrondial DNA traces back 150,000 years and that's not considering that most of the human population was wiped out 74,000 years ago when Mt. Toba decided to become a supervolcano...
“How do you know God did not go back in time and planted the remmants to give man something to do”
More logical is that G_d created the “remmants” when He created the Earth. Not necessary to go back in time, if G_d knows everything and has planned everything from the outset of the creation of the Universe.
Just saying.
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