If anyone looks into the night sky they could see a sky full of stars, planets, glowing gas and clouds of dust but, a most common thing about those objects are, they are all matters. But, this Universe also consists Dark Matter which cannot emit, absorb or reflect light. It could only be observed via its gravitational effects.
An international research team from Max Planck Institute for Extraterrestrial Physics in Germany has explained that the presence of Dark Matter gives extra rotational speed in the star formations when they get closer to the core of spiral galaxies than the outer formations. They have used European Southern Observatory's (ESO) most powerful telescopes to measure the rotational speed of six star generating galaxies. In the journal of Nature, researchers mentioned that the KMOS and SINFONI instruments of those telescopes in Chile helped them to peek 10 billion years old galaxy formation in the distant Universe.
Lead researcher of the study, Reinhard Genzel wrote in his journal,“Surprisingly, the rotation velocities are not constant, but decrease further out in the galaxies”. He explained two main causes for this. First reason is, earlier galaxies were strongly dominated by matters and the second cause is, earlier disc galaxies were much more turbulent than the spiral galaxies.
According to ScienceDaily, both effects helped scientists to mark the time further into early Universe. It took three to four billion years after the Big Bang to transform gas galaxies into flat rotating discs. Surrounded Dark matter halos helped those galaxies to expand and spread out. However, at the time of condensation, it took billions of years longer for dark matter.
Such kind of effects could be seen in today’s galaxy disc’s rotation velocity. With these observations, researchers were able to explain early galaxies were much more gas-rich and compact than today's galaxies. Now, researchers are planning to observe small galaxies of the early Universe to get a better picture of the broader population of galaxies and their evolution.
