The Theory of Relativity challenges the expansion of the Universe
“The expansion of the Universe today is increasing its speed. Understanding the origin of the acceleration is probably the most fascinating question in modern cosmology”, says Luigi Guzzo, Professor of Cosmology at the University of Milan, research associate at INAF and INFN, and a co-author of the paper.
In the standard scenario, this acceleration requires the so-called dark energy to be added to Einstein’s equations, but, in a broader view, it could indicate an incompleteness in the Theory of General Relativity, more precisely a ‘defect’ in its application on cosmological scales.
However, using an innovative approach with experimental data, the researchers have shown that the modification of the General Relativity equations would lead to a Universe in which galaxies behave differently than they do in the real world, as demonstrated in a 2008 paper.
“In this work, we have used the largest map of its kind”, says Jianhua He from Durham University and lead author of the paper. “This has allowed us to reproduce the same type of galaxies in our computer-simulated ‘Universes’ as to make a coherent comparison with the observational data. The novelty of this approach is that it enables us to compare theory and experimental data where it hadn’t been done before”.
The study confirms that Einstein’s theory is unlikely to be incomplete in relation to the Universe’s expansion, reinforcing the hypothesis that dark energy is necessary to explain the behaviour of our Universe.