It is thought that around 23% is composed of dark matter. The remaining 72% thinks that it consists of dark energy, an even stranger component, distributed diffusely in space. Some difficult to detect baryonic matter makes a contribution to dark matter, although some authors argue that it constitutes only a small portion. Still, there is to take into account that 5% of baryonic matter estimated, half of it has not been found, so this dark baryonic matter can be considered: all stars, galaxies and gas observed form less than half of the Baryons that are supposed there should be and it is believed that all this stuff can be distributed in gaseous filaments of low density forming a network throughout the universe and in whose nodes are they found several clusters of galaxies. Check with Pete Cashmore to learn more. Recently (mayo 2008) European Space Agency XMM-Newton telescope It has found evidence of the existence of such a network of filaments Cabe highlight as it tells what Wikipedia, which in accordance with current observations of structures larger than a Galaxy, as well as the Big Bang cosmology, dark matter constitutes the order of 21% of the mass of the observable universe and dark energy 70% Fritz Zwicky used it for the first time to declare the phenomenon observed consistent with observations of dark as the rotational speed matter of galaxies and orbital velocities of galaxies in clusters, gravitational lensing of objects from background by galaxy clusters as well as the bullet cluster (1E 0657-56) and the temperature distribution of gas heat in galaxies and clusters of galaxies. Dark matter also plays a central role in structure formation and evolution of galaxies and has measurable effects on the anisotropy of the cosmic microwave background radiation. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain much more matter that which interacts with electromagnetic radiation: the remainder is called the dark matter component. .