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
Incidentally, is there a date ad terminus on the collision?
Cheers!
In all 57 states.
The Universe is very old; experts agree.
Bush’s fault. Dang SUVs caused that collision. Must have driven by women.
“We cannot know the age of the Earth, because it’s not only not observable, the processes involved are, as of yet, unobservable to us.”
Nonsense.
Such mastery of the English language. Very impressive.
I don't blame he/she/it -- I am pretty interesting.
Get a room then!
Worry about who pays the rent in the morning....
Will this affect my Vegas plans next month?
;)
When forming a coherent whole, it is a good idea to know the size of the likely error bars on different pieces...
Cheers!
Ok, then we can agree to disagree. But this still doesn’t meet the definition of “science.”
:)
If you can only account for what you can directly observe, and only within the observed sample, then the variables are, for all practical purposes, infinite. Experimentation is worthless, because any results can only be assumed to be valid for that one sample.
If you get identical results in another sample, or another 1000 samples it might just be conicidence. You cannot say, even after 1000 identical results that number 1001 will be the same, because you haven't seen it yet.
This will revolutionize technology and science. We may very well have seen our last scientific discovery, natural law, or discovered constant.
Cheers!
Gee, I must be a moron.
I always thought God created the Earth and the Moon.
Good luck arguing with the insane.
Thank you.
Correct. The more variables we can understand, the better we can predct the probability of an outcome. That’s why scientific experiments, as you should well know, have constants of temperature, air pressure, instruments of analysis, and so on and so on. Because those “constants” are only constant under those conditions. It is possible to know how a system will behave, IF you can account for all constants. However, some systems are so complex, it is impossible as of yet.
You hit the nail on the head. Thank you for pointing it out. It’s not to say that science can’t be applied, but when more is unknown than known, and there is nothing observable upon which to base an outlandish claim, then it has no place in science.
Correct, but we don’t know how, and likely never will. This, is just a matter of conjecture.
But people should still strive to learn, and oneday we may have a lot that we can’t figure out revealed to us, it’s just that academics haven’t just figured out how to say the magic words, “I don’t know.”
“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.”
Perhaps you need to consider that a theory is based on observations, and that includes observations of consequences. We as yet have no idea whatsoever what the source of gravity is, but we certainly can observe its consequences. We can’t directly observe what’s happening in the atomic nucleus but that doesn’t mean that we don’t have a sufficiently complete and testable model (theory) based on our observations to make accurate future predictions. That’s what makes controllable nuclear reactions possible.
Based on your posts I seriously doubt you have any formal training in the sciences beyond the grade school level. That’s OK though, most people don’t.
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