A new map of the universe—the most comprehensive to date—boldly goes where no map has gone before. An international team of astrophysicists have crafted a 3D map that includes galaxies from across almost two billion light years. In doing so, they have provided an astrological resource unprecedented in its completeness. The detailed spherical map can be used to more definitely determine how matter is distributed throughout the universe. “The galaxy distribution isn’t uniform and has no pattern. It has peaks and valleys much like a mountain range,” said Professor Mike Hudson of University of Waterloo in Canada, co-creator of the map.
The light blue and white areas of the map represent a denser concentration of galaxies, while the solid blue indicates that these areas have yet to be explored by scientists. The red area is a supercluster of galaxies known as the Shapley Connection.
The star map will specifically serve to shine a light on dark matter, one of the most vexing mysteries of physics. “A better understanding of dark matter is central to understanding the formation of galaxies and the structures they live in, such as galaxy clusters, superclusters and voids,” said Hudson. The majority of mass in the universe consists of dark matter yet it cannot be seen or measured, as it does not emit or reflect light. However, dark matter can be observed in its gravitational shadow, which, as the map documents, has altered the expansion of the universe.
Researchers have previously observed that galaxies move at different speeds, which indicates that the universe is unequally expanding. However, previous maps have not fully incorporated these phenomena, known as peculiar velocities, into the model. The research team hopes to use this recent map to discover what forces are causing this uneven expansion.
The map of the universe has been published online in the well-regarded, peer-review journal Monthly Notices of the Royal Astronomical Society. Hudson, his University of Waterloo colleagues Jonathan Carrick and Stephen Turnbull, and Guilhem Lavaux of the Institute d’Astrophysique de Paris of the Centre national de la recherche scientifique of France contributed to the map’s creation. In collaboration with researchers in Australia, the team will next focus on acquiring more detailed samples of peculiar velocities, so that they may enhance the star map.