Add to ORKGWhy is our universe as we observe it? Will it be the same forever? Understanding the nature of the main constituents of the universe is crucial to obtain a precise description of the way in which it reached its present state. Nowadays, many independent observations support a picture in which the matter content of the universe is shared between an ordinary and observable baryonic component (~5?%) and an invisible dark matter (~23?%). The remaining ~72?% of the universe content is in the form of a completely mysterious dark energy field. This composition emphasizes that, while ~95?% of our universe represents a major uncertainty for us, even the minor contribution from normal and, apparently, known matter entails important challenges for cosm...