X-rays illuminate the interior of the Moon

This is an image of an artificial moon rock sample, measuring about half a millimeter across, made with an electron microprobe at ambient temperature after the experiment with X-rays. 

The fragmentation of the sample occurred when it was extracted from the small diamond cylinder in which it had been melted under high pressure and temperature. Credit: Nature.

Contrary to Earth, our Moon has no active volcanoes, and the traces of its past volcanic activity date from billions of years ago.

This is surprising, because recent Moonquake data suggest that there is plenty of liquid magma deep within the Moon because part of the rocks residing there are thought to be molten.

Scientists have now identified a likely reason for this peaceful surface life: the hot, molten rock in the Moon's deep interior could be so dense that it is simply too heavy to rise to the surface like a bubble in water.

For their experiments, the scientists produced microscopic copies of moon rock collected by the Apollo missions and melted them at the extremely high pressures and temperatures found inside the Moon.

They then measured their densities with powerful X-rays. The results are published in the Journal Nature Geosciences on 19 February 2012.

The team was led by Mirjam van Kan Parker and Wim van Westrenen from VU University Amsterdam and comprised scientists from the Universities of Paris 6/CNRS, Lyon 1/CNRS, Edinburgh, and the European Synchrotron Radiation Facility (ESRF) in Grenoble.

Five decades after the Apollo missions, the formation and geological history of the Moon still hold many secrets. The astronauts not only returned 380 kg of Moon rocks to Earth but also placed many scientific instruments on the lunar surface.

Last year, NASA scientists published a new model for the make-up of the interior of the Moon, using Moonquake data from these Apollo-era seismometers. Renee Weber and her colleagues claim that the deepest parts of the lunar mantle, bordering on the small metallic core, are partially molten, by up to 30 per cent.

In the Earth, such bodies of magma tend to move towards the surface leading to volcanic eruptions. If the deep interior of the Moon contains so much magma, why don't we see spectacular volcanic eruptions at its surface?

Read more of this article here