sentences:  Additional studies, conducted with lasers at the Lawrence Livermore National Laboratory and at the OMEGA laboratory at the University of Rochester show that the magnesium-silicate internal regions of the planet would undergo phase changes under the immense pressures and temperatures of a super-Earth planet, and that the different phases of this liquid magnesium silicate would separate into layers.Further theoretical work by Valencia and others suggests that super-Earths would be more geologically active than Earth, with more vigorous plate tectonics due to thinner plates under more stress.In fact, their models suggested that Earth was itself a "borderline" case, just barely large enough to sustain plate tectonics.