At that time [In the time of Hazrat Mahdi (as)] people will have access to the seven layers of the heavens and the seven layers of earth.
(Bihar al-Anwar vol:52, p. 321)
The hadith refers to information and technological progress that will be forthcoming in the time of Hazrat Mahdi (as). People have recently both explored the depths of the Earth and also acquired the technology with which to learn about the furthest corners of the universe. We now know about the structure of the Earth, from the layers under the crust to the nature of magma. By Allah’s leave, people have now acquired considerable knowledge, from the gases in the layers of the atmosphere to the number of stars in other galaxies. Our Prophet (saas) revealed 1,400 years ago that facts that were unknown in his day would be learned in the time of Hazrat Mahdi (as).