The stars and galaxies visible to the eye represent only one sixth of the total matter in the Universe. The remainder is a mysterious component - dark matter - that neither emits nor reflects light. This is why for astronomers, mapping the whole Universe has been similar to mapping a whole continent from just the lights of the cities.
For the first time ever, astronomers have now drawn a threeódimensional map of how dark matter is distributed across the Univserse. An international team of scientists led by Richard Massey of CalTech, and European members from Marseille, the Max-Planck Institute and Paris, used the COSMOS Survey by the NASA/ESA Hubble Space Telescope for this project.
The results are published in nature online of 8 January 2007, and at the meeting of the American Astronomical Society in Seattle.
This Exchange provides all images, including newly produced 3-D animations of the distribution of the dark matter, to cover this story in a news programme.
The script is online as a PDF file under h

Hubble Unfolds the Universe's Dark Matter.
First 3D map of the Universeís Dark Matter scaffolding
00:00 [Visual starts]
00:03 [Narrator] The stars and galaxies we see in the night sky represent only one sixth of the total matter in the Universe. The remainder is a mysterious component - dark matter - that neither emits nor reflects light. So, for astronomers, the challenge of mapping the Universe has been similar to mapping a continent from just the lights of the cities.
Stars and galaxies Earth with city lights
00:21 For the first time ever, astronomers have been creating a threeódimensional map of how this dark matter is distributed across the Universe. To this end, an international team of scientists, among them groups from Marseille, the Max-Planck Institutes and Paris have been using data from the NASA/ESA Hubble Space Telescope. The results are published in nature online of 8 January 2007, and at the meeting of the American Astronomical Society in Seattle.