In prehistoric caves, humans already drew rudimentary maps of their immediate environment on the walls. If today our entire Planet seems to have been mapped with some precision, this might not be quite the case for our Universe. Thanks to a new way of exploiting the available data, researchers reveal that it could ultimately not be so « grumeleux » that they had first imagined.
Galaxies, stars, planets. Starting from a mattermatter projected by the Big Bang, our UniverseUniverse has become huge. In order to have any hope of understanding the forces which played a part in arriving at this point, those which, over billions of years, have shaped the world around us, scientists know that they need to establish a map which will give the distribution of matter in the Universe as we observe it today. This is precisely what researchers, in particular from the University of Chicago (United States) and the Fermi National Accelerator Laboratory (United States), present today. The one they claim to be the most accurate map ever made.
Two sets of data — those of the Dark Energy Survey (Chile) and those of South Pole Telescope (AntarcticAntarctic) –, more than 150 astronomersastronomersthree published papers and, among other discoveries, the fact that matter is not as « grumeleuse » than provided by the best model currently available. Something to think – once again – that something could be missing in the standard model in question.
To understand how the researchers arrived at this conclusion, it is necessary to know that the two instruments from which they analyzed the data are very different. The idea behind the Dark Energy Survey, was to survey the sky for six months from the top of a mountain. the South Pole Telescopehe had rather the ambition to find the faint traces of radiation from the first moments of the Universe and which still travel in our sky.
A disagreement with the standard model of cosmology?
Combining these two sets of data provided the researchers with a cross-check of their results. A way to ensure the robustness of their measures. Measurements of gravitational lenses. The bending phenomenon of light that astronomers observe as it passes through a region with high gravitygravity. A way, for them, of locating classical matter just as well – the one we know well and that we feel around us every day – and the one that astronomers call black matterblack matter — a form of matter that still keeps its mysteries, but still exerts a force of gravity.
Result: almost everything seems to correspond to the forecasts of the standard model of cosmologystandard model of cosmology. Nearly ? Because the researchers realized that their conclusions are very slightly different from what this model draws. Namely, a Universe in which matter forms like “lumps”.
So, is there something missing from this famous standard model of cosmology? Or is it the distribution map of matter in the Universe that needs to be reviewed? The authors of this work recognize that a more in-depth study will be necessary to decide. One thing is certain, and that is that the strategy they have deployed of working on two very different sets of data, of adopting in a way two different points of view on the Universe, seems likely to bring new lights. This is exciting news as more and more large telescopes will be put into service in the coming years.
