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most of the planets of the Solar System have satellites. For example, Mars has two moons, Jupiter 79 and Neptune 14. Some are icy, others rock, others are geologically active, but they also are with little or no activity. But, how did they get up there? Do you all formed the same way? What we could tell about the origins of our cosmic neighbourhood?
do Not go very far so that the questions appear. We’re still not entirely sure about how it was formed our satellite, while the most accepted theory is that a body the size of Mars, called Theia, collided with the proto-Earth. Our planet ended up being the “ eldest son ” of this collision, and retained enough heat to become tectonically active. However, the Moon, the smaller, probably cooled down faster and remained frozen geologically. However, since the Apollo missions, it is known that there is some activity on the Moon, which collides with this explanation. What happens then?
A new research published in “Nature Geoscience” suggests that this is because the radioactive elements are distributed in a peculiar way after the catastrophic collision formed the Moon. At the time of the collision, and mixed the components of Theia and the prototierra. After, they were separated rapidly in a few million years. Thanks to the dynamics of the collision that formed the Earth-Moon system , the Earth has a capacity to retain volatile substances such as water, or gases that form the atmosphere, and have enough internal heat to maintain the volcanism, planetary and long-term tectonics. Decades of observations have shown that the history of lunar was much more dynamic than expected, with volcanic activity, and magnetic, which occurred just 1000 million years , much later than thought at first.
And this separation also constribuyó to the faces on the visible and hidden of the Moon are very different. On the surface, on the near side of the Earth, can be seen with the naked eye in dark spots and clear. Early astronomers called these dark regions “maria”, which in Latin means “seas”, thinking that it was indeed a mass of water. But using telescopes, scientists were able to discover more than a century ago that these were not actually seas, but rather craters or volcanic features. And, at that time, the science was assumed that the other side, the hidden, was the same. But it is not.
The face that hides the source
in the late 1950s and early 1960s, uncrewed space probes launched by the USSR showed the first images from the other side of our satellite , moment in which the scientists were the surprise: it had almost no ” seas “. Only 1% of the far side was covered with “mary” in comparison with 31% for the face nearest to you. In addition, the crust is thicker, with a different composition of the near side. The surface is also much paler, with less staining of basalt and covered with craters.
This is interpreted as the basalt flows on the near side covered a large amount of craters of the Moon, but why the near side had more volcanic activity in the far side has been a mystery big enough that the scientists moles, have wanted to resolve. In addition, there is something more peculiar in the visible: a region geoquímicamente strange call Procellarum KREEP Terrane.
The mysterious KREEP
With the collection of samples from the Apollo missions, the scientists quickly discovered that the relative darkness of these patches was due to its composition, geological and, in fact, were attributable to volcanism. They also identified a new type of firm rock, which they called KREEP : an abbreviation of rock enriched in potassium (chemical symbol K), group elements rare earth elements (REES, including cerium, dysprosium, erbium, europium, and other elements that are rare on Earth), and phosphorus (chemical symbol P), which was associated with the seas. It also contains elements such as uranium and thorium, whose radioactive decay produces heat.
Concentrations of thorium corresponding to KREEP – NASA
This Procellarum KREEP Terrane appears to be associated with the plains of basalt, and it has been shown previously that its properties of heat generation you could have something to do with the volcanism prominent on the side visible. In fact, the thermal modeling of the interior lunar suggests that the radioactive decay of potassium, thorium and uranium could have provided a heat source to the near side for thousands of millions of years.
Mixing KREEP with moon rocks
Now, an international team of scientists from the Institute of Science of the Terrestrial Life of the Tokyo Institute of Technology, the University of Florida, the Carnegie Institution for Science, Towson University, the Johnson Space Center of NASA and the University of New Mexico carried vabo a series of experimental determination to measure the effect of KREEP in the lunar rock.
Mixed composition is KREEP with synthetic analogues of lunar rocks at concentrations of 5, 10, 15, 25, and 50 percent of KREEP. These were kept at temperatures ranging between 1.175 and 1,300 degrees celsius for four to eight days. The effect was dramatic: the presence of KREEP synthetic in the mix reduced the melting point of the analog , producing between two and 13 times more melt than in the control experiments without KREEP. And this without the contribution of the radiative heat.
To see what happens when this radiative heat is added to the mix, the team carried out a numerical modelling. And they discovered that the compounds of warming radioactive, are the effect of KREEP. Together, the two could have contributed to the volcanic activity on the near side of the Moon , resulting from her dark regions that we see today.
where did this come From?
where did the KREEP? It is a question that you don’t know the answer for sure, although it is probably a result of how it was formed the Moon : the impact of Theia in the prototierra and the heterogeneous mixture of both bodies. Therefore, better understanding how it was formed Tercel Procellarum KREEP and the way in which it affected the internal processes on the Moon may help us better understand how you got there.
“Due to the relative lack of erosion processes, the surface of the Moon recorded geological events of the early history of the Solar System”, explains in a press release scientific planetarium Matthieu Laneuville , the Earth-Life Science Institute in Japan. “In particular, the regions on the near side of the Moon has concentrations of radioactive elements such as uranium and thorium, unlike any other place in the satellite. To understand the origin of these enrichments local uranium and thorium can help to explain the early stages of the formation of the Moon and, as a consequence, the conditions on the primitive Earth.”
in Addition, Laneuville believes that the evidence of this type of process self-amplifiers are not symmetrical could be found not only on other moons in our cosmic neighbourhood, but to be general trend in the rocky bodies of the universe .