Earth is much younger than previously thought


13/07/2010

According to data in the new study, the Earth is younger and formed three times longer than previously thought.

The researchers estimated that the formation of the planet could take much more time after the birth of the solar system, which was 4567 billion years ago.

Comparing isotopes taken from the earth’s mantle with isotopes of meteorites, geologists from the University of Cambridge have concluded that the planet has reached its present size of about 4467 billion years ago.

In the past, scientists have estimated that the development of the Earth, in a process known as accretion (accretion) when the gas, dust, and other materials gathered together to form the planet was just 30 million years.

But new research has shown that this process could take more than 100 million years - more than three times longer than previously thought.

Writing in the journal Nature Geoscience, the researchers explained that the Earth has grown to 60 percent of its present size relatively quickly, but then the process slowed down and took a total of about 100 million years.

"The main thing is to deal with the amount of time formed the core of the Earth, which is still unknown to this area of science," - said John Rudzh, one of the authors of the study at Cambridge University.

"One of the problems is that scientists usually assume that the accretion of the Earth took place in an exponentially decreasing rate.

"We believe that it is not so simple, and it could well be more confusing, repeatedly interrupted and again starting the process."

The accretion of the Earth included a series of collisions of large pieces of debris, known as planetary embryos.

These collisions, creating a huge temperature, making the interior of the growing planet to melt, forming the center of the Earth’s core of molten metal, covered with top crust.

Many scientists believe that the final part of the process occurred when the body about the size of Mars collided with the Earth by splitting a piece of the planet, which became the moon.

The team of scientists measured the levels of isotopes that were created during the accretion of the Earth. The level of isotopes is a bit of geological hours.

Then compared the levels of isotopes on Earth with samples taken from the meteorites that fell to our planet in our time.

These meteorites represent a kind of time capsule, in which the level of isotopes approximately corresponds to that at the beginning of the formation of our solar system.

The difference in the level of tungsten isotopes from the Earth and meteorites, helped define the duration of the formation of the Earth.

Dr. Rudzh colleagues have used computer models to calculate the way the Earth’s formation, in accordance with the level of decay of isotopes found in the Earth’s mantle.

They showed that the Earth could not be generated for 30 million years, but the first stage of the formation was the fastest, and took 10 to 40 million years, during which the Earth has risen to two-thirds of its present size.

Then, the process of acceleration slowed down, and continued for over 70 million years.

"If the calculations are correct, it could mean that in total, the Earth formed over 100 million years," - said Dr. Rudzh.

"According to our calculations, this means that the Earth is billions of years 4467 - almost a child, compared with the age in 4537 billions of years, as previously thought. Visit a news portal, argue, argue, prove.

Original: Telegraph.co.uk


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