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'Giant Impact Theory' of Moon's Origin --Nixed by New Research



New research from geophysical scientist Junjun Zhang and colleagues at Origins Lab at the University of Chicago, suggests that the giant impact hypothes of the creation of the Moon might be wrong. The team found   that in comparing titanium isotopes from both the moon and the Earth, that the match is too close to support the theory that the moon could have been made partly of material from another planet.

According to the giant impact hypothesis, there was once a Mars-sized body referred to as Theia orbiting in our solar system. Theia would have formed in about the same orbit as Earth, but about 60° ahead or behind.  When the protoplanet had grown to be about the size of Mars, its size made it too heavy for its orbit to remain stable. As a result, its angular distance from Earth varied increasingly, until it finally it crashed into the Earth.

The collision would have occurred 4.533 billion years ago when Theia would have hit the Earth at an oblique angle, and destroyed itself in the process. Theia's mantle and a significant portion of the Earth's silicate mantle were thrust into space. The left over materials from Theia mixed with the materials from the Earth and eventually formed the Moon.

Earlier research validating this hypothesis, was conducted by cientists from Oxford University, University of California, and Swiss Federal Institute of Technology, who  compared silicon isotopes from Earth rocks, as well as other materials from our solar system such as rocky materials from meteorites showing that the Earth’s core and the Moon’s core contain the same silicon isotopic material, which would support that the two were once a single body until a large impact separated them.

Up to about 2,900 kilometers (1,800 miles) into the Earth (not quite half way to the center), is what we know as the mantle and crust. They are predominantly formed of silicate, a compound mad of silicon, oxygen, and other elements. Past the halfway mark is a dense metallic iron material that makes up the Earth’s core.

The multinational team found that the heavier isotopes from silicate samples taken from the Earth consisted of increased amounts of the heavier isotopes of silicon. They found that Mars, the asteroid Vesta, and various chrondites (primitive meteorites that never produced ainner cores) do not contain such an arrangement, even though they have an iron core. is much smaller than the Earth (about one-eighth the size), so did not have enough mass to generate the pressure necessary to form the same core as found in the Earth.

On the other hand, the researchers found that the Moon did show a similar composition of the silicon isotopic composition as the Earth. However, it, too, is much smaller than the Earth—about one-fiftieth as large as the Earth and about one percent of the Earth’s mass—making it even less likely to have been able to generate enough pressure to form an Earth-like iron core.

However, such a core does exist at the center of the Moon, but no one can explain how it got there.
The researchers contend that the Moon indeed must have been created during a giant impact by a planet-size object (Theia) that hit during the early development of Earth. The impact was large enough that the materials, which eventually formed the Moon, mixed with the materials from the Earth, which already had a heavy silicon isotopic composition.

“The similar isotopic composition of the bulk silicate Earth and the Moon is consistent with the recent proposal that there was large-scale isotopic equilibration during the giant impact,” they wrote in a paper published in the journal Nature.

This research was the first of its kind using isotopes in this manner and offers intriguing insights into the creation of Mars, the Earth, and the Moon. It may also help explain how life evolved on the Earth and whether or not it might have existed at some time on Mars.  

Now, Zhang's research at the University of Chicago shows that although scientists had already found that oxygen isotopes from the Earth’s mantle and the moon were nearly identical, that wasn’t enough to put a dent in the theory that a collision with Theia had created the moon because oxygen isotopes from the Earth could have mixed with isotopes from the mass of molten material circling the planet after impact. Because titanium isotopes are not nearly so easily exchanged, it’s difficult to theorize that the same sort of mixing could have occurred.

Most scientists agree that if a planet had smacked into Earth and the moon came about as a result, than the moon ought to be made of some of that other planet as well. Some say the laws of physics suggest it would be somewhere in the neighborhood of forty percent. If that’s the case, why don’t studies of rocks brought back by the Apollo missions show evidence of this other planet?

Image at the top of the page is an infrared camera image from the moon taken with the Lunar Crater Observation and Sensing Satellite (LCROSS) mid-infrared camera. 

More information: The proto-Earth as a significant source of lunar material, Nature Geoscience (2012) doi:10.1038/ngeo1429

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Image credit: NASA/JPL

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Actually, this discovery merely supports Dr. Michael Kerjman's ideas of the Universe formation provided with "The X-Challenge: Realm of Senses"

@P.T. Really! The artical you linked is either far too brilliant for me or unhinged meanderings of a deluded soul. (Probably the later). And seems more pseudo-scientific prose than a scientific paper:
"The more self-conscious product affected the more resistible to cooking process such stuff is.
This resistance towards wrath of a nature is a further object of consideration."

The heat and pressures of such a collision chemically alters the materials during/after the impact - what happened was a HUGE meteorological event billions of years ago. The article doesn't really sound right.

speculation, both pointless and misleading!

not to mention a waste of all our time and resources, work on what we, as a race and as a planet need here, and what we have right now, and we might just survive the next 1000 years.
long enough to get some decent evidence about the unimportant lump of rock next door :)

Theory states that since we don't see other world isotopes on the moon, it could not be from a renegade planet hitting the earth. major logic flaw, how do you know what are original earth isotopes and what are original other work (Thea) isotopes? Since the 2 possibly crashed 4.5bn years ago, both have a similar mix of both worlds, therefore isotopes we assume are earths in the 40% of crust and mantle formed possibly by the crash could be from Thea. And just because you found no isotopes from Mars or other planets means nothing, if Thea and Earth were in similar orbits I'd expect them to have similar isotopes, and different from say Mars (also they both have similar cores, Mars does not)

I never have believed in the giant impact hypothesis. Fairly soon after the formation of our solar system, all planets and their moons – and everything else - became stable in the orbits.
As our Solar System once was formed out of a molecular cloud, it is very logical to assume that the Earth and the Moon was mostly created from the same particles.
Personally, I am convinced that our solar system was created directly out from the galactic centre; out in the bars where both the rotation and orbiting momentum was created in an electromagnetic double helix swirl or vortex, all caused by the swirling momentum in the galactic centre.
Such a formation process can confirm the “galaxy rotation anomaly” where all objects in the galaxy is orbiting the galactic centre with the same orbital speed compared to each other and to the centre.
Seen in this perspective, all planets and their moons have had some 4.6 billion years to become stabilized. And all the gasses and particles have then been distributed already in the nuclear centre process in the galactic centre. (Where there is no black hole, but a funnel of creation in a electromagnetic 3D spherical circuit)

Ivar Nielsen
Natural Philosopher

I tend to go along with zetavu's analysis. Dr. Zhang's work is good work, but I think he and his team failed to account for how similar two planets are likely to be when they form under nearly identical circumstances. Dr. Zhang's team also does not propose an alternate hypothesis that would just as effectively explain the moon's slow outward spiral from Earth.

I'm no genius in astro physics but wouldn't an impact like that have signs. Like a continent sized crater? With that kind of impact there must be signs of it here on Earth?

Is it just me or does this posting become incoherent after the 4th paragraph?

The answer is probably Uranus

As Plossible as the other one

I go along with Ivar. Not sure about the vortex idea but if energy from the AGN can be deposited as mass in the galactic equatorial rim, that would make sense.

Otherwise, instead of an impact 4 bya, perhaps the iron core Earth gave birth in much the same manner as Cass A did 300 ya.

We look at novas and tag their explosive products with names according to weight, well, why don't they like O Manuel's Iron Sun in which our light-weight sun also collapsed in a heating even producing an iron core? Perhaps the possibility that another heating could cause Sol's iron core to give birth? Mythology says Jupiter gave birth from its iron womb--Venus. So light weight bodies can give birth as long as they have an iron womb.

Look at Earth's strange iron core. It has been reduced to a marble rolling around the wall of an iron shell. Where is the iron? On top in batholiths? Deccan traps? Why does not Ibex and Sundo tell us about the iron core of Earth? Did the iron core of Earth give birth to the Moon?

Finally! Let go of the Greek and seek the truth! :)
The formation of the earth gave birth to the moon.
Volcanic activity from the magnetic pole only needed to blast (around 17,000 feet?) in order to account for earth material on the moon.
The chicken laid an egg.
The residual formed a super continent such as Rodinia.
Water entered the south magnetic pole and bled through the north over the land.
The rest is history.

Late arrival ---- like the moon. Lunar origin was something as follows: the moon formed as a sloughing product of Mercury when the inner planets were young: it spent most of its life orbiting Venus: it was captured by Earth approx. 540 mill. yrs ago (beginning of the Cambrian). Large quantities of Mercury were splashed to Earth's orbital influence at the time of lunar formation. This donated material went to forming our continental rock masses. Hence the chemical similarities. The real clincher here is that it is suspected we do have samples of Mercury -- aubrite meteorites -- and these meteorites are exceptional in being isotopically similar to Earth and Moon. All this was published years past. , see Common Donor Capture Moon Origin.

then, where is the asteroids (shredded portions) of earth and moon. atleast some of them will survive from the collision with the mother planets.

So this means that all the trace substances with their detailed characteristics of the Moon samples are equal to Earth. Apollo samples were completely dry - whereas Russian Luna samples contained rather much water - which was also found from US samples "later". But Russian samples do not have those isotope problems and their composition sounds much more likely.

Did the Apollo astronauts transport the rocks from Earth to Moon and returned them back? Would this solve all the problems?

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