The world of science has never been more prolific than it is nowadays. A team of 300 experts from six different countries have gathered at the Dark Energy Survey (DES) to create the first dark matter map. They are to present their findings today, during the American Physical Society meeting which is held annually in April. These findings will be published on the Arxiv preprint server.
In astronomy, dark matter exists only hypothetically and scientists say that it comprises a part of the total mass of the universe. It neither emits nor absorbs light or electromagnetic radiations and it cannot be seen by using telescopes. It is estimated that it represents about 83% of the matter of the universe. Because it is not visible, it cannot be proved, but scientists believe in its existence because it would be impossible to explain the galactic structure of the universe if it wasn’t there.
The creation of the map was no easy task. It involved the use of a 570 megapixel camera that produced images from the Victor Blanco Telescope. This telescope is currently at the Cerro Tololo Inter-American Observatory in the Chilean Andes, placed on the mountain top. For now, the data released does not cover more that 0.4% of the sky, but in the future it might reveal more than 12% of it.
But how does this wonderful map function, one might wonder. Due to the fact that dark matter does not emit any radiations, it can only be perceived because it warps and lenses light issued by galaxies that are far away. This enables scientists to detect distortions created by the dark matter’s gravitational movements of light. The aim was to tell which parts of the universe have more dark matter, according to Sarah Briddle, an Astrophysics Professor at the University of Manchester. Two million galaxies have been measured so far with the help of this map to an accuracy of within 0.1%. The imprint of those tiny warps of light are combined, enabling the map to reveal where exactly dark matter is heavier in that particular part of sky. According to astrophysicists, the theories have so far been confirmed. Therefore, it has been proved that because dark matter exists in a higher proportion than visible matter (4%), galaxies were born in places with a larger concentration of dark matter, where gravity is stronger.
The map’s role is to show what role dark matter has in forming galaxies. It is considered to be an amazing tool because, even if it is not the first matter map, its uniqueness prevails from its ability to detect, in a very detailed manner, how dark matter is spread on a very big patch of the sky.
The creators of the map began collecting data on August 31, 2013. The survey is bound to go on for another three years, in the attempt to test the theory of dark energy and develop means to measure in a more accurate way the speed at which our universe is expanding.
Image Source: lsst