An international team of planetary scientists has solved the mystery about the age of the Moon and came to the conclusion that it is about 60 million years younger than previously thought. This finding came with the discovery and use of so-called “geological clock.” Scientists say that the Moon was most likely formed when billions of years ago the Earth collided with a planet that was about the size of Mars. According to the results of previous studies, most of them believed until now that this happened about 30 million years after the formation of our solar system.
In recent days, a group of scientists from France, Germany and the United States discovered that Moon is millions of years younger than we thought. They made the discovery on the basis of previous analysis from Earth’s interior, as well as by using new computer simulations of the protoplanetary disk from which our planet formed. The researchers simulated the growth of Mercury, Venus, Earth and Mars from the disk of thousands planetary building blocks in orbit around the Sun. In order to determine the age of the Moon, they created 259 simulations and used them to analyze the growth history of these terrestrial worlds. They accomplished the mission and the mystery is now finally solved.
Scientists found a link between the time when the Earth collided with the larger planet which resulted in the formation of the Moon, and the amount of material that has been added to our planet after the collision. With the discovery of “geological clock,” for the first time in history, scientist can determine the age of the objects and discover the history of the solar system without relying on measurements and analysis of the decay of radioactive elements. Information about the weight that the Earth gained when Moon was formed, were taken from previous studies which have also shown that the abundance of iron group elements in the Earth’s mantle is directly proportional to the mass, which was released in a collision.
John Timmer from Ars Tehnica explained that new study is using a clever way to provide an estimate. The fact is that the last big impact in the Earth’s history did not mean that Earth will escape further bombing from space. He added that the logic is pretty wise. At the time of the Moon-forming impact, the entire Earth was melted and that allowed the iron to sink to the core. After the last big collision that formed the Moon, iridium, platinum and some other elements should be almost completely gone from the Earth’s mantle. Although in small quantities, those elements are still in the mantle and that suggests that after the moon-forming collision, a very small quantity of material accreted onto Earth.
New method of determining the age, therefore, indicates that the moon is about 4.47 billion years old, which means that it arose about 95 million years after the formation of our solar system. According to that, the Moon is approximately 60 million years younger than we thought for many years. Now that the mystery of the Moon’s age is solved, scientists will focus on researching the other planets in our solar system.
By: Janette Verdnik