The mantle, by contrast, was seen as little more than a thick layer of hot rock, with the occasional plume pushing its way through. Now, the team on this new effort reports that a lot more is ...

The next layer is the mantle. Many people think of this as lava, but it's actually rock. The rock is so hot, however, that it flows under pressure, like road tar. This creates very slow-moving ...

"Only models with a softer layer at the bottom of the mantle match all our measurements ... this research has the texture of the kind that opens the door to further revelations in lunar geology.