Dark Matter From 12 Billion Years Ago Detected For the First Time

Scientists have discovered dark matter around galaxies that existed about 12 billion years ago, the earliest detection yet of this mysterious substance that dominates the universe. Space.com reports: The findings, achieved by a collaboration led by researchers from Japan's Nagoya University, suggest that dark matter in the early universe is less 'clumpy' than predicted by many current cosmological models. If further work confirms this theory, it could change scientists' understanding of how galaxies evolve and suggest that the fundamental rules governing the cosmos could have been different when the 13.7 billion-year-old universe was just 1.7 billion years old. The key to mapping dark matter in the very early universe the cosmic microwave background (CMB), a sort of fossil radiation left over from the Big Bang that is distributed throughout the entire cosmos. [...] The team combined lensing distortions of a large sample of ancient galaxies with those of the CMB to detect dark matter dating back to when the universe was just 1.7 billion years old. And this ancient dark matter paints a very different cosmic picture. "For the first time, we were measuring dark matter from almost the earliest moments of the universe," [University of Tokyo assistant professor Yuichi Harikane said in the statement]. "12 billion years ago, things were very different. You see more galaxies that are in the process of formation than at the present; the first galaxy clusters are starting to form as well." These clusters can be comprised of between 100 and 1,000 galaxies bound to large amounts of dark matter by gravity. "Our finding is still uncertain," Harikane said. "But if it is true, it would suggest that the entire model is flawed as you go further back in time. This is exciting because if the result holds after the uncertainties are reduced, it could suggest an improvement of the model that may provide insight into the nature of dark matter itself." The team will continue to collect data to assess whether the Lambda-CDM model conforms to observations of dark matter in the early universe or if the assumptions behind the model need to be revised.

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