An international team of astronomers has produced a map that covers a billion light-years worth of dark matter in the universe. Never before has dark matter been mapped on such a large scale.

Two members of the team, Catherine Heymans of the University of Edinburgh and Associate Professor Ludovic Van Waerbeke of the University of British Columbia in Vancouver, Canada, presented their findings at the 119th meeting of American Astronomical Society, held last week.

The project took place at the Canada-France-Hawaii Telescope Lensing Survey (CFHTLensS) in Hawaii and collected data from the Canada-France-Hawaii Telescope Legacy Survey. For more than five years, the team accumulated images of ten million galaxies – six billion light-years away – from four different regions in the sky during each of the seasons. Essentially peering at the universe when it was but six billions years old, they studied  how dark matter warped the light emitted by the galaxies.

The process of producing the map was completed through a method called gravitational lensing, in which bodies (e.g. galaxies, or, in this case, dark matter) are so massive that they curve space-time and distort light, making it travel in a curve, rather than in a line. By studying the distortions of the galaxies’ light, the team was able to determine the structure of the dark matter and plot its distribution.

“It is fascinating to be able to ‘see’ the dark matter using space-time distortion,” says Waerbeke at the American Astronomical society meeting. “It gives us privileged access to this mysterious mass in the Universe which cannot be observed otherwise. Knowing how dark matter is distributed is the very first step towards understanding its nature and how it fits within our current knowledge of physics.”

The universe is more or less a cosmic web of dark matter and galaxies. Dark matter is impossible to be detected by itself, making it seem invisible, though it makes its presence known through warping space-time and light. The mysterious substance makes up a whopping 23 percent of the universe, with dark energy taking up 72 percent and everything else (stars, planets, etc.) only 4 percent.

With creating such a large map of the cosmic web, astronomers and cosmologists are becoming closer to understanding the nature of dark matter and, ergo, a large portion of the universe. Dr. Heymans, a lecturer of physics and astronomy, says, “By analyzing light from the distant Universe, we can learn about what it has travelled through on its journey to reach us.

We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe.”

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About the author

Sarah Hansen
Sarah is currently earning her M.F.A. in Creative Nonfiction at Sarah Lawrence College. She has an avid interest in the sciences, particularly astronomy, and hopes to one day publish works of fiction, poetry, and creative nonfiction.