Colliding Galaxy Clusters Suggest Dark Matter Is even Stranger Than Once Thought
The “stuff” which makes up 85% of the entire mass of the universe is called dark matter. It is usually considered as a sort of mysterious and invisible matter. But a new study observes that it can be even more enigmatic and even harder to detect, far more than what it’s perceived by astrophysicists.
The chief cause behind invisibility of the dark matter is that it hardly interacts with anything. In other words, it does not emit radiations which can make it observable like stars and other cosmos elements.
Researchers attempted to explain the effects which dark matter produces on collisions between galaxies. Results of the study are outlined in Science Magazine.
Conducting this study, astrophysicists used two space telescopes to observe 72 collisions between galactic clusters. Hubble Space Telescope was employed to record the visible light while X-rays were recorded by the Chandra Observatory.
During these collisions, the scientists tried to track the movement of stars, clouds of gas, and dark matter. Researchers were able to observe the movements of gas clouds and stars but dark matter remained almost undetectable. Why? Actually, extremely hot clouds of gas glowed and thus were easily detected by Chandra. Similarly, stars were observable in visible light using the Hubble.
“Looking through dark matter is like looking through a bathroom window,” said Dr Richard Massey from Durham University, one of the study’s authors. “All the objects that you can see in the distance appear slightly distorted and warped.”
The reason for distortion and warping of the dark matter is “gravitational lensing.” This is the effect which explains why the stars are so hard to be seen. Although Dark matter does not emit observable light but it does possess gravity. Due to this gravity, it diverts the direction of any light passing nearby.
Researchers observed the galaxy clusters because they stored both dark and ordinary matter in abundance. By observing the behavior of ordinary matter, they successfully located dark matter.
“We like these collisions because it’s exactly what we’d do in the lab. If you want to figure out what something is made out of, you knock it, or you throw it across the room and see where the bits go,” Richard Massey of Durham University said.
The study has opened up couple of new horizons for further research and has averted couple of old theoretical models to explain dark matter. The existence of the mysterious matter in cosmos was theorized in 1960s, which this study corroborates.
Meanwhile few other theories were postulated which predict that such collision can slow the pace of dark matter’s movement — which the recent study confutes.