For a long time, scientists believed that the Moon is a completely dead planet in geological terms.
Re-analysis of data collected by seismometers missions “Apollo”, helped scientists to prove that the interior of the moon continued to cool and to produce seismic tremors. Their findings were presented in the journal Nature Geoscience.
“We assume that the eight aftershocks that we found in the data with “Apollo”, was generated as a result of shifts of layers in that moment, when the moon acted tidal forces, and its bark has accumulated a sufficient amount of energy as a result of its cooling and contraction. This suggests that the Moon is still “alive” from the point of view of tectonics,” said Thomas Watters (Thomas Watters) of Smetanova Institute in Washington (USA).
For a long time, scientists believed that the Moon is a completely dead planet in geological terms – its depths have long grown cold, and no tectonic or seismic activity, they should not persist.
These perceptions were questioned after the scientists studied images collected by the American probe LRO since its arrival in lunar orbit in June 2009. In these photos, scientists discovered a special form of relief – the so-called fault escarpments, a kind of “folds” of rocks, resulting from the displacement of the two layers relative to each other.
Such structures, as it is now, planetary scientists believe, arose in the relatively recent past of the moon, no more than 50 million years ago by the cooling of its rocks. This again forced them to argue about when the companion of the Earth has ceased to be geological activity and if it was actually.
Watters and his colleagues found the first “real” evidence that the interior of the moon remain active at least half a century ago, studying the data that was recording seismometers installed on the surface of the companion of the Earth by astronauts of various missions program “Apollo”.
For eight years, these sensors have recorded 28 of relatively weak shocks, presumably occurred at the surface of the moon. Before the LRO, scientists did not attach much significance to this, considering the consequences of falls are small or medium asteroids.
At the moment, the NASA probe has opened more than 3,5 thousand of such “scars” on the moon, which gave the Watters ‘ and his team the opportunity to test whether they were associated with the aftershocks that were recorded by instruments of the participants of the expedition “Apollo-12”, “Apollo 13”, “Apollo-15 and Apollo-16”.
To do this, scientists had to create a special algorithm that allowed them to exactly compute the epicenter of these aftershocks, whose position was originally defined with extremely low quality. In parallel, the geologists said the depth at which any of these fluctuations, and have compared both of these options with the recent images from LRO.
It turned out that eight of the 28 were tremors in the vicinity of relatively fresh fault scarps, and their focus is on the “right” depth. Almost all bursts happened in the moment when the Moon was or at the very large distance from Earth, or was extremely close to her.