http://www.digitaljournal.com/article/360992

Earth's water probably came from early asteroid strikes

Posted Oct 27, 2013 by Andrew Ellis
There is a strong possibility that asteroid strikes, which occurred over a billion years ago, gave Earth a very good portion of its water.
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According to LiveScience, scientists released a study that suggests Earth got a lot of its water roughly 4.6 billion years ago when asteroids crashed to the ground. These crashes supposedly happened just after the solar system itself was first formed.
Scientists studied the Tagish Lake meteorite that landed in Canada's Yukon Territory in January of 2000, according to Mashable. They concluded from evidence that the water "in its parent asteroid disappeared soon after the space rock formed, when its insides were still warm." It also resulted in the scientists concluding that asteroids that "slammed into Earth" several hundred million years after the solar system was born were probably pretty dry.
As the lead author of the study, Yuki Kimura, from Japan's Tohoku University told LiveScience in an email:
"So, our results suggest that the water [was] supplied to Earth in the period when planets formed rather than the period of late heavy bombardment from 4.1 billion years to 3.8 billion years ago."
Mashable said that the scientists believe this rock, which is officially called a "carbonaceous chondrite," came from an asteroid that came from the "main belt" between Mars and Jupiter.
The scientists then proceeded to use a "transmission electron microscope" to observe the particles of magnetite, according to LiveScience. The tiny particles then put themselves into three-dimensional "colloidal crystals."
Kimura said that the crystals, according to Mashable, can be formed during the transition from ice to vapor. He said that this "implies" that most of the asteroid's water disappeared during the beginning stages of the solar system's formation before the rock's insides had the opportunity to lower its temperature.
"Further analysis might give us some information about evolution of organic molecules in the early solar system," Kumari told LiveScience.