Scientists build simulations to solve dark matter question
The answers could be found at the edge of the galaxy
'Dark matter' makes up as much as 80 per cent of our universe, according to some theories - but it emits no energy and scientists can't detect it, casting doubts upon its existence - until now.
Scientists from the University of Bonn and the University of California at Irvine, have developed sophisticated computer simulations to devise a test to determine whether dark matter is a thing, or if Newton's gravitational law need to be modified.
Detailed in a fresh study published in the Physical Review Letters, the research shows that the answer could be hidden in the motion of the stars within small satellite galaxies swirling around the Milky Way.
Using one of the world's most powerful supercomputers to conduct the research, the scientists simulated the matter distribution of the so-called satellite "dwarf" galaxies, that is, small galaxies that surround, for instance, the Milky Way or Andromeda.
Focusing on a relationship called "radial acceleration relation" (RAR), the studies suggested that in disk galaxies, stars move in circular orbits around the galactic centre, and the acceleration that forces them to constantly change direction is caused by the attraction of matter in the galaxy.
The RAR also described the relationship between this acceleration and the one caused by the visible matter only, and provided an insight into the structure of galaxies and their matter distribution.
"We have now simulated, for the first time, the RAR of dwarf galaxies on the assumption that dark matter exists," explained professor Dr. Cristiano Porciani of the Argelander Institute for Astronomy at the University of Bonn.
Another researcher, Emilio Romano-DĂaz, added: "It turned out that they behave as scaled-down versions of larger galaxies… In this case the RAR of dwarf galaxies depends strongly on the distance to their parent galaxy, while this does not happen if dark matter exists."
This difference makes the satellites a powerful probe for testing whether dark matter really exists, but the scientists admit it will probably take years to solve this riddle.
"Individual measurements are not enough to test the small differences we have found in our simulations," added doctoral student Enrico Garaldi. "But repeatedly taking a close look at the same stars improves the measurements every time. Sooner or later it should be possible to determine whether the dwarf galaxies behave like in a universe with dark matter, or not."