The dark matter is a mysterious material component probably consisting of elementary particles but in no case of normal matter, that is to say protons, neutrons and electrons, and which is supposed to be distributed throughout the observable universe. Without electric charge and interacting only very weakly with the normal material, it is marked by its gravitational pull.

Il ne faut surtout pas la confondre à l'antimatière dont on sait que la curieuse absence au niveau cosmologique, alors qu'elle devrait être aussi abondante que les particules de matière normale, constitue une énigme toujours irrésolue.

The question of the existence of dark matter

There is ample evidence for the presence of dark matter, be it galaxies, clusters of galaxies, but also the birth of galaxies via fossil radiation. However, this evidence is indirect. We would like to be able to manufacture these non-baryonic particles by accelerator, detect them with experiments like Coupp and Picasso or in space with AMS.

What is Dark Matter and Dark Energy?

But it may be that we are going wrong and that we should review the law of gravitation on the scale of galaxies and clusters of galaxies. Various theories have been proposed, especially the one known as Mond and his relativist avatars.
While the Cold Dark Matter (CDM) model seems solid and most favored by experience, it is not free of defects and some disagreements between its predictions and reality are known. It may well be that both theories are necessary to account for observations. One can not completely dismiss the hypothesis that it is really necessary to do without dark matter and consider only theories like Mond.
A very small part of the dark matter is undoubtedly composed of neutrinos. For the rest, if it exists well, we have proposed black minitrous, supersymmetric particles, axion and quite often what are called Wimps.

Mysteries of a Dark Universe