Cosmologists weigh cosmic filaments and voids

Cosmologists weigh cosmic filaments and voids: While galaxies and filaments have more mass than the average regions of the universe, voids have less mass than average. This unbalanced distribution causes matter to rapidly move away from voids and towards the concentrations of mass along the cosmic filaments that lie between them.

"This means that voids act like objects with an effectively negative mass," Clampitt said, "such that even light rays bend away from them. They act roughly like concave lenses, the opposite of big galaxies, which act like convex lenses..."

Their results show that voids are not as empty as they appear. Dark matter and other dim structures permeate all the way to the center of the voids.

Dark matter underpinnings of cosmic web found

Dark matter underpinnings of cosmic web found: The massive filament's gravity focuses the light travelling towards Earth from more distant background galaxies. The team used this light to calculate the filament's mass and shape. X-rays from the hot gas of normal matter in the vicinity showed that this matter lined up with the filament but made up only about 10 per cent of its mass. The rest must be dark matter...

Largest dark matter map holds clues to dark energy

Largest dark matter map holds clues to dark energy: Heymans's team used the Canada-France-Hawaii Telescope to observe 10 million galaxies, each about 6 billion light years away. The researchers analysed the images to build a map of dark matter spanning 10 billion light years, the first direct glimpse of dark matter on such a large scale.
The map shows a great cosmic web, with scattered clumps of dark matter linked by wispy filaments...
The map also reaffirms the need for dark energy to account for the accelerating expansion of the universe. Some proposed alternatives say that, instead of invoking a whole new entity, physicists might simply need to tweak Einstein's theory of general relativity on very large scales. But the new map, which spans very large scales yet is consistent with general relativity, lets the air out of those theories. "So far," says Miller, "there is no observational evidence for any departure from Einstein's theory."