FRANCE: By observing multiple collisions between huge clusters of galaxies, scientists have witnessed dark matter coasting straight through the turmoil.
Dark matter is the mysterious, invisible stuff that makes up 85% of the matter in the cosmos – and these results rule out several theoretical models put forward to explain it.
This is because it barely interacts with anything at all, including the dark matter in the oncoming galaxies.
The work appears in Science magazine.
To conduct their study, astrophysicists looked at 72 smash-ups between galactic clusters, using two space telescopes: visible light was recorded by the Hubble Space Telescope, and X-rays by the Chandra Observatory.
Scouring multiple views of the collisions, the researchers tracked the movement of the three main components of galaxies: stars, clouds of gas, and dark matter.
The violently swirling clouds of gas are hot enough to glow with X-rays, which Chandra detects. And stars can be seen in regular, visible-light images from Hubble.
