The best dark matter map to date raises questions about the universe
The cosmos is smoother than you think.
Scientists in the Dark Energy Survey have just released the best dark matter map yet, but it's not answering every question — if anything, the cosmos may be more mysterious than ever. As BBC News, Nature and Fermilab report, the survey of 5,000 square degrees used weak gravitational lensing (in this case, how gravity from nearby galaxies affects views of distant ones) to look for large patches of dark matter in relatively close sections of the universe.
The data also helped studies into dark energy, the as yet unexplained force that seems to be accelerating the universe's expansion. The team produced a 3D map thanks to redshifting, or the tendency of objects to appear increasingly red with distance.
Team members conducted observations using the 570-megapixel camera of the Victor M. Blanco telescope, at Chile's Cerro Tololo observatory, between 2013 and 2019.
While the high detail is helpful, it also validated concerns that have been floating for years. The DES results indicate that the universe is slightly smoother and more uniform than expected. While that largely supports current theories that dark energy is a constant, the discrepancy is enough that researchers might have to rethink existing ideas. The universe may not behave quite like scientists thought, and the dark matter map could lead to new models that challenge previous assumptions.