In the universe, ordinary matter is made up of the planets or stars that we see shine and represent 5%, and the rest is in the form of dark matter and energy, which remains invisible and mysterious. Knowing the nature of the latter remains a mystery to physics.
The Dark Energy Survey (DES) project was born to “closely examine” dark energy that, according to cosmologists, produces a rapid expansion of the universe that counteracts the force of gravity. Now, over 400 scientists from 7 countries in 30 articles are publishing the results of three years of mapping nearly an eighth of the celestial globe.
The result is the creation of the largest and most concise maps (2D and 3D) of the distribution of matter in the modern universe and the “most accurate” observation of its evolution, with an analysis whose conclusions conform to the predictions of a model, the standard of cosmology, the authors say.
Photography of the night sky made possible thanks to a 570 megapixel camera installed in the Victor Manuel Blanco telescope at the Pan American Observatory in Cerro Tololo (Chile), a telescope from the 1970s, said Ramon Mikel, director of the institute explaining to the Efe of Physics of High Energies of Barcelona ( Spain), that it was “overly designed, like Soviet spaceships, and it takes what you throw at it.”
In this case, one of the most powerful cameras designed specifically for DES and assembled and verified at Fermilab in Chicago.
Although DES has made observations for six years, what is being presented now is an analysis of data from the first three years (2013-2016): 226 million galaxies were observed in 345 nights, of which 100 million are used for these studies.
The maps map both ordinary matter and dark matter in the universe to a distance of up to 7 billion light-years, according to Fermilab’s details.
In their analysis, the researchers compared the results to measurements from the European Space Agency’s Planck Space Observatory, which used optical signals known as microwave background radiation to observe the early universe, about 380,000 years after the Big Bang.
These data provide a very accurate view of what the universe was like 13 billion years ago, and the standard cosmic model predicts how the distribution of dark (and ordinary) matter has evolved to this day.
Although the results published now are consistent with the expectation, there is still evidence, both in DES and in other experiments, that the material in today’s world is distributed in a small proportion, more evenly than expected, “an interesting discovery that deserves more research.” .
Dark matter, whose existence was formulated more than half a century ago, does not emit light but exerts gravity; It represents 25% of the universe.
Dark energy (70%) is different: it was believed that the expansion of the universe was a product of the Big Bang in which everything originated. It has been accepted that at some point this expansion will end up slowing down due to the opposite effect of the force of gravity holding the material together, but this is not the case.
According to Einstein’s theory of general relativity, gravity should cause a slowdown in the cosmic expansion. However, in 1998, two teams studying distant supernovae found that the expansion of the universe was accelerating.
Something is thought to be creating more and more space between galaxies: dark energy. It is a constant that has yet to be understood and is one of the biggest challenges in physics.
This competition between energy and dark matter and how the former will develop has a future interest, according to Mikel’s details. If the universe continues to disintegrate, within billions of years, galaxy clusters will be divided into galaxies, galaxies into stars, and stars into atoms …
But if this is not the case, and the gravity of matter wins, then a major collapse will occur, adds the scientist, which indicates that at the moment – these are now millions of years – there is a “equilibrium”, and that is why there are galaxies and planets and “people are wondering about the origin of the universe.” And its development. “
Mikel summarizes that the Standard Model “works well”, even though it contains “weaknesses”: its two most important components, dark matter and energy, “we don’t know what they are”; This is exactly what DES intends to explain, although at present the data “fit reasonably well” with the aforementioned model.
Analyzing the data for the next three years does not think it will give big surprises, but soon another generation of experiments will begin over a period of ten years during which more than 3 billion galaxies will be observed.
“Maybe here we will discover more things, if not approach the problem from another perspective, beyond mapping galaxies.”
Articles are published in the arXiv repository (without review by other experts), although they have already been submitted and are still being referred to scholarly journals. | By Noemí G. Gómez / EFE