CSIC is about to publish a White Book to define its scientific strategy for the coming decades. The White Book contains chapters on 14 different thematic areas. One of the main goals of this exercise is to increase collaboration between research groups and institutes of the CSIC. Particular value is set on inter- and cross-disciplinary work. Each thematic area defines a set of “challenges”, key scientific questions for the coming decade(s) in which the CSIC has or can achieve national and international leadership. The future allocation of resources in the CSIC will take these challenges into account. The challenges will be revised every four years. Here we present the ten challenges of Thematic area 9 "Understanding the basic components of the Universe, its structure and evolution.