An international team of researchers has created the largest and most detailed map of the distribution of so-called dark matter in the Universe.

The results are a surprise because they show that it is slightly smoother and more spread out than the current best theories predict.
The observation appears to stray from Einstein's theory of general relativity — posing a conundrum for researchers.

Dark Matter is an invisible substance that permeates space. It accounts for 80% of the matter in the Universe. Astronomers were able to work out where it was because it distorts light from distant stars. The greater the distortion, the greater the concentration of dark matter.

Dr Niall Jeffrey, of École Normale Supérieure, in Paris, who pieced the map together, said that the result posed a "real problem" for physics.
"If this disparity is true then maybe Einstein was wrong," he told BBC News. "You might think that this is a bad thing, that maybe physics is broken. But to a physicist, it is extremely exciting. It means that we can find out something new about the way the Universe really is."