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The Giant Impact Theory  (Source: starchild.gsfc.nasa.gov)
Two new studies attempt to prove the Giant Impact Theory in different ways

Two different studies say they've found evidence supporting the theory that the moon was created from a collision between Earth and a Mars-sized body.

The Giant Impact Theory, which was proposed back in 1975, suggests that the early Earth and a Mars-sized planet called Theia collided with one another. This completely obliterated Theia, and its composition created a ring around Earth and eventually came together to create the moon.

While scientists have been able to explain how this event occurred, one major thing didn't add up: the composition of the moon.

Scientists long believed that for this theory to be true, the moon would have to be composed mainly of Theia's elements. Moon rocks from that were brought to Earth were studied, and surprisingly, they had the same types and amounts of elements that the Earth had, including titanium, silicon and oxygen. This didn't make sense, and has left the theory wide open for the last 30+ years.

However, scientists from Washington University in St. Louis managed to measure a small excess of a heavier variant of zinc in moon rocks from that were brought to Earth in the 1970s. They believe the excess is due to heavier zinc atoms condensing out of the collision's cloud faster than the lighter zinc atoms, and the vapor that remained escaped before it condensed.

This bit of sorting by mass is called isotopic fractionation, and it's what scientists have been looking for all along. This shows that the moon rocks were depleted of easily evaporated elements called volatiles, and a large collision could explain this depletion while other theories can't.

"The magnitude of the fractionation we measured in lunar rocks is 10 times larger than what we see in terrestrial and Martian rocks," said Frédéric Moynier, PhD, from Washington University in St. Louis. "So it's an important difference."

But the Washington University team isn't the only one to bring new evidence to the table. Robin Canup, a planetary scientist from the Southwest Research Institute Colorado, used Harvard scientists' findings to create a theory of her own related to the collision.

According to the Harvard team, which used computer simulations to create its theory, ancient Earth had to have been spinning too fast for today's 24-hour rotation. They suggested that early Earth and a body half the size of Mars could have collided where both were obliterated and combined elements to create both the moon and Earth's heavy iron core/lighter rock layers.

At a later point, Earth's rotation could have slowed due to the moon and sun aligning in a way that changed Earth's orbit.

Canup used the idea that Earth's rotation was slowed and came up with the theory that two bodies similar in size collided at a slow speed, and their materials merged to create the Earth and moon.

Source: Science Daily



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RE: *sigh*
By JNo on 10/21/2012 8:36:27 PM , Rating: -1
Yes but gravity and relativity (and evolution) are extremely widely accepted and proven theories so the meaning of the handle "theory" has changed compared to the context of this particular theory.

I don't think you really know the scientific meaning s of the word.

Your arrogance continues.

"I understand that you probably have a quota on articles to write, but you really need to understand the material before you write, first."

I understand that you probably understand your job very well but you obviously don't understand that other people have different specialisations and roles. You honestly expect a tech blogger to have a high level understanding of *every* topic they publish?! (Like you've got doctorates in medicine, zoology, chemistry, mathematics and psychology....) Then they wouldn't be a tech blogger. Just because this is your forte I can understand your indignity.

However, if you understand how news is generated and procured, replicated, edited and published, you'd understand of course that 99% of *every* article can be considered bu11shit/inaccurate to those close to the source and with specialised understanding.

You really need to understand the limitations of published news media before you publically mouth off first.


RE: *sigh*
By Goty on 10/21/2012 11:44:49 PM , Rating: 5
Actually, none of these theories have been proven. That's the crux; to be scientific a hypothesis must be disprovable, so absolute proof is unobtainable.

As to the rest of your self-righteous ranting, since when is it wrong to expect a journalist to inform themselves on a subject before publishing or to exhibit self-control in abstaining from adding extraneous, made-up statements to an article instead of making a five minute visit to Wikipedia beforehand? Laziness is not an excuse for poor writing.


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