Yale scientists (Jennifer Girard et al.) conducted the first laboratory deformation experiments on materials in the Earth’s lower mantle under the conditions equivalent to the top of the lower mantle of the Earth (27 GPa, 2100 K). The results were published in Science in the January 8th issue. Many questions on the global dynamics of Earth are closely related to the rheological properties of materials but the experimental studies on rheological properties at ~20 years ago were limited to low pressure range (<3 GPa) due to technical difficulties. In Karato’s lab at Yale, they spent ~20 years to develop a new deformation apparatus called RDA (rotational Drickamer apparatus). This work provides the first data set to understand a range of observations in geochemistry and geophysics and considered as a ”breakthrough in high-pressure mineral physics” (“Perspectives” by Jiuhua Chen).