Dwarf galaxies suggest dark matter theory may be wrong

Prof Carlos Frenk at Durham University, working with the Virgo Consortium, now has data suggesting that our understanding of the formation and composition of the Universe is incomplete.

These data come from an unlikely source: dwarf galaxies, a "halo" of which surrounds our own Milky Way.

These dwarf galaxies are believed to be mostly made up of dark matter, and contain just a few stars. Their dimness has made them difficult to study in the past.

But the Virgo Consortium has created computer simulations to visualise how the dwarf galaxies formed, using their assumptions about CDM.

The team found that the final results of these simulations did not at all match what we observe. The models showed many more small galaxies in a wide halo around the Milky Way, whereas in reality there are fewer, larger dwarf galaxies.

Prof Frenk explained that there were two "equally disturbing possibilities" for why this is the case.

One idea is that many dwarf galaxies formed as in the simulation, but there were violent supernova explosions during their formation that radically changed the structure of the dwarf galaxy halo.

"If this were the case, it would mean that galaxy formation is a much more exciting process than we thought," said Prof Frenk.

But there are still uncertainties over whether the small fraction of normal matter in the Universe (4%) could have such a fundamental effect on the structure of the dark matter.

An alternative cause for the discrepancies between the modelled data and what we observe is much more fundamental: that CDM does not exist, and the predictions of the standard model relating to it are false.

Prof Frenk said that after working for 35 years with the predictions of the standard model, he is "losing sleep" over the results of the simulations.

vía BBC News – Dwarf galaxies suggest dark matter theory may be wrong.