Posted on 07/08/2014 10:35:49 AM PDT by robowombat
New evidence supporting moon formation via collision of 2 planets by Staff Writers Oxford, UK (SPX) Jun 09, 2014
A new series of measurements of oxygen isotopes provides increasing evidence that the Moon formed from the collision of the Earth with another large, planet-sized astronomical body, around 4.5 billion years ago. This work will be published in Science* on 6th June, and will be presented to the Goldschmidt geochemistry conference in California on 11th June.
Most planetary scientists believe that the Moon formed from an impact between the Earth and a planet-sized body, which has been given the name Theia. Efforts to confirm that the impact had taken place had centred on measuring the ratios between the isotopes of oxygen, titanium, silicon and others.
These ratios are known to vary throughout the solar system, but their close similarity between Earth and Moon conflicted with theoretical models of the collision that indicated that the Moon would form mostly from Theia, and thus would be expected to be compositionally different from the Earth.
Now a group of German researchers, led by Dr. Daniel Herwartz, have used more refined techniques to compare the ratios of 17O/16O in lunar samples, with those from Earth. The team initially used lunar samples which had arrived on Earth via meteorites, but as these samples had exchanged their isotopes with water from Earth, fresher samples were sought.
These were provided by NASA from the Apollo 11, 12 and 16 missions; they were found to contain significantly higher levels of 17O/16O than their Earthly counterparts.
Dr Herwartz said "The differences are small and difficult to detect, but they are there. This means two things; firstly we can now be reasonably sure that the Giant collision took place. Secondly, it gives us an idea of the geochemistry of Theia. Theia seems to have been similar to what we call E-type chondrites.
"If this is true, we can now predict the geochemical and isotopic composition of the Moon, because the present Moon is a mixture of Theia and the early Earth. The next goal is to find out how much material of Theia is in the Moon".
Most models estimate that the Moon it is composed of around 70% to 90% material from Theia, with the remaining 10% to 30% coming from the early Earth. However, some models argue for as little as 8% Theia in the Moon. Dr Herwartz said that the new data indicate that a 50:50 mixture seems possible, but this needs to be confirmed.
The team used an advanced sample preparation technique before measuring the samples via stable isotope ratio mass spectrometry, which showed a 12 parts per million (+/- 3 ppm) difference in 17O/16O ratio between Earth and Moon.
measuring the ratios between the isotopes of oxygen, titanium, silicon and others.
These ratios are known to vary throughout the solar system, but their close similarity between Earth and Moon
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And your theory for the formation of the moon with earth’s ratios of these isotopes is?
Moon has a Theiatrical debut.
You truly missed the point of it all ...
Good luck. I suspect it will take all the mental effort you can muster.
"What's your degree in? Dentistry?"
Did you even read the article? Or comprehend what was written?
Obviously not.
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