February 4, 2016   |   admintam
February 4, 2016
The study which was published in the Journal Science Magazine was conducted by six distinguished scientists at the University of California, Los Angels (UCLA). According to the study, the early Earth was mixed with a baby planet called Theia following a head on collision.
The collision between the early Earth and Theia was said to be too violent that it also formed the moon.
In the past, it was believed that the Moon was created when a smaller planet called Theia grazed the Earth and broke up, sending a smaller chunk into space where it was caught in Earth’s gravity. In 2014, a team of German scientists reported that the Moon also has its own unique ratio of oxygen isotopes, different from Earth. But this new study has refuted this claim by the Germans.
The scientists said if that was the case, the Moon would have a different chemical composition to the Earth, because it would be made up, predominantly, of Theia.
The scientists based their argument after studying Moon rocks brought back by astronauts on the Apollo missions. They discovered that the Moon rocks oxygen isotopes are the same as on Earth.
The researchers said they analyzed seven rocks brought to the Earth from the Moon by the Apollo 12, 15 and 17 missions, as well as six volcanic rocks from the Earth’s mantle — five from Hawaii and one from Arizona.
The key to reconstructing the giant impact was a chemical signature revealed in the rocks’ oxygen atoms. More than 99.9 percent of Earth’s oxygen is O-16, so called because each atom contains eight protons and eight neutrons.
However, there are also small quantities of heavier oxygen isotopes: O-17, which have one extra neutron, and O-18, which have two extra neutrons.
Therefore, the authors concluded that the collision between Theia and the early Earth was so violent that the two planets effectively melded together to form a new planet, a chunk of which was knocked off to form the Moon.
The researchers said they used state-of-the-art technology and techniques to make extraordinarily precise and careful measurements, and verified them with UCLA’s new mass spectrometer.
Lead author of the study and professor of geochemistry and cosmochemistry at UCLA, Edward Young said “We don’t see any difference between the Earth’s and the Moon’s oxygen isotopes; they’re indistinguishable. Theia was thoroughly mixed into both the Earth and the Moon, and evenly dispersed between them. This explains why we don’t see a different signature of Theia in the Moon versus the Earth.”
The early Earth crash with Theia is said to have happened approximately 100 million years after it formed, almost 4.5 billion years ago. The study said early Earth collided with Theia at an angle of 45 degrees or more. The scientists described the collision as a “powerful side-swipe.”
Professor Young also said Theia did not survive the collision, except that it now makes up large parts of Earth and the Moon. He predicted that Theia was growing, and probably would have become a planet if the crash had not occurred. Theia was said to be approximately the same size as Earth.
According to Telegraph, early Earth collision with a possible different planet was first theorized in 2012 by Matija Cuk, a research scientist at Search for Extraterrestrial Intelligence Institute, and Sarah Stewart, a professor at University of California, Davis; and separately during the same year by Robin Canup of the Southwest Research Institute, all in the United States.
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