Dark matter is an enigmatic type of matter. The human eye cannot see it so it is more like a hypothetical substance. It is considered that dark matter binds galaxies together. Moreover 80% of the matter in the Universe consists of dark matter. According to scientists dark matter must exist because otherwise the Universe could not be explained.
Cosmologists have created for the first time a huge map of the distribution of dark matter in the Universe. Thy managed to track the invisible matter by observing the gravitational effects it has on light. The map contains voids and clumps of dark matter from 2 million galaxies and it presents characteristics hundreds of millions of light years across.
This research was conducted by DES (Dark Energy Survey), an international group consisting of more than 300 scientists from 6 countries. The map was presented on April 13, at the annual meeting of the American Physical Society. The findings were presented by Chihway Chang from the Swiss Federal Institute of Technology in Zurich. The paper will also be published in Monthly Notices of the Royal Astronomical Society.
In order to create the map scientists used a 570-megapixel camera which was mounted at the Cerro Tololo Inter-American Observatory in the Chilean Andes, on the Victor Blanco telescope. The prelimiinary data contains only 0.4% of the sky. However the goal of DES is to obtain a map presenting one-eighth of the sky.
Compared to the visible matter, there is five times more dark matter in the Universe. Some may wonder how can it be detected if invisible. Well, the answer is simple: dark matter affects the space-time continuum. Large concentrations of this matter can bend the light from background galaxies distorting our images of them.
Astrophysics Sarah Bridle of the University of Manchester explaine that their goal was to make the invisible visible and be able to determine which parts of the sky have more dark matter and which has none. She confessed that this is what they had dreamt of all this time.
The study won’t stop here. The team of researchers intends to verify how many galaxy clusters can be detected by the Dark Energy Camera. In addition they plan to examine sound waves in order to see how the universe is expanding. The Big Band left left an imprint in the galaxy distribution when sound waves were created hundred of thousands of years ago. If scientists manage to measure the position of galaxies they will be able to determine the patter of that imprint and use it to make assumptions about how the Universe has been expanding.
Image Source: SLAC Today