For decades, physicists are trying to unravel the mystery of the formation of the Moon. While it was suggested several possible models, no one stood out as a particularly nice – until now. In the new study, the researchers argue that the only natural satellite of our planet, formed after a collision with a planet the size of Mars, which is emitted from the surface of the liquid magma of the early Earth into space. This magma solidifies along with a small proportion of the impactor material to form a month, as we know it today.
Magma may be the key to the formation of the Moon
Most of today's lunar model layer can at least agree on one thing – that the Earth was formed about 4.5 billion years the Moon, which connects the system shortly after two planetesimals collided violently. «Giant Impact hypothesis" explains the many features that we see today on the Earth and the Moon, for example, their relative size and speed. But he has a great disadvantage that the shortcomings of the whole model – the chemical composition of the Moon.
Now we know that most of the bodies in the solar system have unique chemical compounds and therefore should month. However, the lunar rocks brought home during the Apollo missions show that their isotopic fingerprints are almost identical to the Earth's minerals.
In order to accommodate this major disagreement, researchers have developed all kinds of alternative models. One of the most extravagant models proposed by physicists at the University of California, Davis, and Harvard University argue that hereditary clash appeared early Earth in a giant donut planetary sized sprayed rocks called «Synestia» (from the "synthesis", "together" and "Hestia" Greek Goddess architecture and structures). According to this theory, pieces of molten rock, which have been thrown into orbit after a pin formed seed to Moon. Synestias probably not for a long time – no more than a couple of hundred years – because they can not maintain their heat shrinking rapidly, and finally destroyed in the molten planet. And while Earth-synestia gradually decreased, evaporate silicate rock in the rain prot moon, which explains how the moon has inherited its structure from the Earth. Another model suggests that the planet, which has faced in the proto-Earth rotates rapidly. Both models are plausible, but unlikely. They simply involved too many "ifs."
For comparison, the new model proposed by scientists at the Japan Agency for Marine-Earth Science and Technology in Yokohama and Yale sounds closer to reality.
Investigators argue that shortly after the Earth formed, it was covered with sea hot magma, while acting on the & # 39; object was probably made of solid material. The team conducted computer simulations, showing that the impact will be warmed magma is much more than solids from the effects of the & # 39 object. According to this simulation, the magma increases of & # 39; volume and shoots into orbit to form the moon, explaining why there is much more material in the Earth's monthly makeup. Even a glancing blow from the hammer would have been enough to bring down more than 70% of the lunar formation of debris from the magma ocean.
"In our model, about 80% a month is made from materials of the proto-Earth," said co-author, Shun-Ichiro Karato, geophysicist at Yale. "In most of the previous models, about 80% of the Moon consists of a drummer. It's a big difference. "
This new model confirms previous theories about how the moon formed, without the need to provide non-standard conditions of clashes – but this is not the final word on this issue too. Japanese researchers have found that the amount of debris from the impact was comparable to the current mass of the Moon. Preliminary work, however, believes that the garbage should be equal to about three to four times greater than the mass of the Moon. In the future, the researchers will be to fix the other variables, such as the mass of the impactor and its spin to see if the amount of generated waste is better suited.
Results & # 39 appeared in the magazine Nature Geoscience.