7 Dec 2016

Analysis of a giant new galaxy survey, made with ESO’s VLT Survey Telescope in Chile, suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought

Scientists have gained fresh insight into dark matter, the elusive material that accounts for much of the Universe’s mass. Calculations based on a study of distant galaxies, using a powerful telescope, suggest that dark matter is less dense and more smoothly distributed throughout space than previously thought.
The results, from an international team of scientists, will inform efforts to understand how the Universe has evolved in the 14 billion years since the Big Bang, by helping to refine theoretical models of how it developed.

Scientists studied wide-area images of the distant universe, taken with the VST (VLT Survey Telescope, realized by Italian National Institute of Astrophysics) based in the European Southern Observatory in Chile.
They applied a technique based on the bending of light by gravity – known as weak gravitational lensing – to map out the distribution of dark matter in the Universe today. Their study represents the largest area of the sky to be mapped using this technique to date. To eliminate bias in their results, scientists carried out three sets of calculations, including two false sets, only revealing to themselves at the outcome which of the sets was real.

Intriguingly, the results of their analysis appear to be inconsistent with deductions from the results of the European Space Agency’s Planck satellite, the leading space mission probing the fundamental properties of the Universe. In particular, the KiDS team’s measurement of how clumpy matter is throughout the Universe — a key cosmological parameter — is significantly lower than the value derived from the Planck data