measured in such detail. The results suggest the filament has a high mass and that if these measurements are representative of the rest of the Universe, then these formations may contain more than half of all the mass in the Universe.
Researchers analyzed images of a 60 million light-year strand of dark matter around the massive galaxy cluster MACS J0717. The galaxy cluster is one of the largest yet seen and is about 5.4 billion light-years from Earth. Data was used from the Hubble Space Telescope, as well as Japan’s Subaru Telescope and the Canada-France-Hawaii Telescope as well as spectroscopic data on the galaxies within it from the Keck and Gemini Observatories.
Einstein’s general theory of relativity imparts that massive objects, including dark matter, warp space and time around them, causing light passing through to travel along a bent and curved path. Filaments thus distort the images of galaxies in the background and the researchers were able to convert the image distortions into a map of the dark matter.
A model that combined positional and velocity information for these galaxies was created and this then revealed the 3D shape and orientation of the structure. As a result, scientists were able to measure the exact properties of this mysterious filamentary structure without the uncertainties and biases that come from projecting the structure onto two dimensions, as was done in the past in such analyses.
The results obtained push the limits of predictions made by theoretical work and numerical simulations of the cosmic web. With a length of 60 million light-years, the filament’s sheer size is extreme. Researchers say that if it is representative of other strands, then these strings might contain even more dark matter than theorists had previously predicted. [x