The study revealed how the dark matter in the cluster of galaxies behaves when the clusters collide.
Dark matter makes most of the mass of the universe. It does not emit, reflect or absorb light this makes it very difficult to detect.
It can be traced by measuring how it wraps space through gravitational lensing. In this method light form the distant source would be magnified and distorted by the gravity of dark matter.
From the observation of the Hubble telescope and Chandra X-ray observatory, astronomers found that dark matter did not slow down when it collided with itself, indicating that it interacts with itself very less than previously thought.
This finding has narrowed down the options of what this substance might be.
Hubble is used to map distribution of stars and dark matter after a collision using gravitational lensing.
Chandra is used to detect X-ray emission from colliding gas clouds.
Galaxy cluster mainly consists of galaxies, gas clouds and dark matter.
During the cluster collision the gas clouds surrounding galaxies crash into each other and they slow down or stop but this does not affect galaxy because there is huge gap between stars within galaxy which does not slow each other down.
The astronomers found that the dark matter continued just like the galaxy after the collision and didn’t slow down much.
This means that the dark matter does not interact with the flies of dark matter or with the visible particles.
If the dark matter dragged against each other then the distribution of galaxies would have shifted.
This helped the scientist to eliminate many dark matter properties previously estimated and now they have to work with the finer set of unknowns to build their models.