Astronomers reach new frontiers of dark matter

For the first time, astronomers have mapped dark matter on the largest scale ever observed. The results reveal a Universe comprised of an intricate cosmic web of dark matter and galaxies that spans more than one billion light years.

Their project, known as the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), analysed images of about 10 million galaxies in four different regions of the sky collected over five years. They studied the distortion of the light emitted from these galaxies, which is bent as it passes massive clumps of dark matter during its journey to Earth.

Galaxies included in the survey are typically six billion light years away. The light captured by the telescope images used in the study was emitted when the Universe was six billion years old - approximately half the age it is today.

The team’s result has been suspected for a long time from studies based on computer simulations, but was difficult to verify owing to the invisible nature of dark matter. This is the first direct glimpse at dark matter on large scales showing the cosmic web in all directions.

Above: The observations show that dark matter in the Universe is distributed as a network of gigantic dense (light) and empty (dark) regions, where the largest dense regions are about the size of several Earth moons on the sky. The densest regions of the dark matter cosmic web host massive clusters of galaxies.