There is a partially molten layer between month‘s rocky mantle and solid metallic core are now more likely, thanks to studies of its changing shape and gravity.
Researchers from NASA Goddard Space Flight Center and the University of Arizona analyzed new data that explains the moon’s stiffness under the influence of Earth’s and sun’s gravity. Finding that mass is unlikely to be completely solid.
Rather, the moon’s mantle has thick, slimy zones that rise and fall like the tides.
“Internal modeling shows that these values can only be matched to the low viscosity zone (LVZ) at the bottom of the lunar mantle.” write The researchers state in their published paper:
The idea of this non-solid layer is surfaced by researchers Although it has existed for decades, until now, the available data have not allowed us to definitively determine whether this layer actually exists..
Under the influence of the gravitational pull of the Earth and the Sun, the Moon experiences tidal effects. This is not from an oceanic perspective, but due to physical deformations in the Moon’s shape and gravitational field.
For this study, the team used new measurements obtained by NASA. Gravity recovery and internal laboratory (Grail) and lunar reconnaissance orbiter. These measurements allow researchers, for the first time, to estimate the moon’s tidal changes on an annual basis.
Computer models describing the properties of rocks deep inside the Earth-orbiting moon show that the layers beneath the solid mantle must be at least somewhat viscous for the numbers to fit.
That raises more questions. How did this zone get there? And what makes it so hot? More research is needed to know for sure, but the team behind the study believes that titanium iron oxide minerals: ilmenite may be involved.
“The presence of an LVZ at the base of the Moon’s mantle may be most easily explained by partial melting of an ilmenite-rich layer, which would make the Moon more Moon-like. ” Marswhere Partial melting was recently inferred From analysis of earthquake data, write researchers.
As with the study of Earth, determining what lies hundreds or thousands of kilometers below the surface requires some guesswork, but it’s all based on what we know about the moon and the planets. That’s a very educated guess.
It is known that the mantle above this LVZ is mainly made of minerals. olivineAnd that it has quite a story to tell over billions of years. If we are able to set up a permanent base on the moon within the next few years, seismic measurements taken from the moon’s surface itself should allow us to learn more about what’s going on beneath the surface. is.
“The existence of this zone has important implications for the thermal state and evolution of the Moon.” write researchers.
This research AGU progress.
