Volcanoes were active on the Moon two billion years ago. It is much smaller than the previous measurements. A group of international researchers have come to that conclusion thanks to two new moon rocks launched late last year by the Chinese unmanned lunar mission Chang 5 5. Brought to earth. Researchers Published by This week’s results Science.
The Moon is 385,000 km from Earth. It is much smaller than Earth (3,474 km in diameter), but is the fifth largest of the more than 200 moons in the Solar System.
There were active volcanoes on the moon. The surface is scattered with cooled lava, and some of the rocks brought to Earth by previous lunar missions contain basalt. This type of rock is formed by volcanoes. The eruptions are probably like hotspot volcanoes like in Hawaii. In this process, a portion of the Earth’s crust melts from the local constant flow of hot and partially melted rock from the bottom. As the pressure under the thin crust increases, the magma explodes through the crust.
While satellite images of the Moon indicate recent volcanic eruptions in some places, only evidence of active volcanoes at least three billion years old has been found. Of the 380 kilograms of rocks brought to Earth by the Apollo missions until 1972, there was not a single volcanic rock less than three billion years old, including rocks from other missions and lunar meteorites.
Carefully selected location
But between the new moon samples there were now two rocks from smaller volcanoes. These stones were collected by the Chinese robot lander Changi 5. It crashed into the Oceanus Prosollar, a large lava plain on the Moon late last year. Carefully selected location. The moon there is much smaller than the rest of the moon. After shoveling and drilling, Changi 5 lifted a pill full of rocks into the moonlight orbit. The rocks were sent to Earth in orbit around the moon for research in the Mothership Lab. Analysis of different variants of lead in individual basalt fragments has shown that volcanic rock is about two billion years old.
“Exciting discovery,” VM van Westrenen, a lunar researcher at VU University Amsterdam, was also not included in the study. “Two billion years ago, according to models, the mantle of the volcano cooled too much. However, the heat-generating elements in the mantle are likely to reheat the magma locally.” Previously a hotspot would be created. Strangely, no heat-generating elements were found in the new samples.
Does this mean that a still unknown process will cause a new volcanic eruption on the moon? “It’s not really possible. The moon cools much faster than the earth. The moon is very small, there is no atmosphere. There is no water to facilitate the melting of rocks.
According to Bart Root, a planetary researcher at Delft University of Technology who has not been involved in the study, the most interesting thing about the discovery is that it allows planetary researchers to estimate the geographical age of other celestial objects. “To do that, we use a lunar – based model. In an Earth lab, it’s taking samples of rocks, so far we only have them from the moon.
A version of this article also appeared on NRC Handlesblad on October 8, 2021
A version of this article also appeared in the NRC on the morning of October 8, 2021
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