An international team of astronomers has succeeded in mapping the ‘dark’ (invisible) matter in the Universe, as seen in 50 different directions from the Earth. They find that, within the uncertainty, it is unlikely that mass alone would stop the current expansion of the Universe.
This fundamental result is based on the powerful, but challenging method of ‘cosmic shear’. It depends on very accurate measurements of the apparent, weak distortion and preferential orientation of images of distant galaxies.
This effect is caused by deflection of the light from those galaxies by the large mass concentrations in the Universe it encounters on its way to us. The larger these masses are, the larger are the apparent image distortions and the more pronounced are the alignments of neigbouring galaxy images.
The new analysis was made possible by means of unique observational data, obtained under excellent conditions with the the ESO 8.2-m VLT ANTU telescope and the multi-mode FORS1 instrument at the Paranal Observatory.
The full text of this Press Release, with a photo showing a sky field with images of distant galaxies observed with the VLT for this research programme, and compared with a reconstructed map of the distribution of mass in this direction, is avialable at:
