From cosmic cyberattacks to everything about the Sun: Catalan scientists want to understand the mysteries of the Universe

GenevaSome problems are so complex and ambitious that they can only be addressed through interdisciplinary collaborations between different research teams. The Synergy grants awarded annually by the European Research Council aim precisely to foster synergies between various teams, enabling them to tackle these challenges. The projects selected in the latest call for proposals span diverse categories, from sociology and governance to molecular biology and cancer. Only 66 proposals were ultimately selected, among more than 700 submissions from institutions around the world. Two projects led by Catalan institutions, which aim to better understand the workings of the Sun and the expansion of the Universe, are among the winners.

A cosmic "cyberattack"

One of the award-winning projects involves the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), which is leading an international collaboration to address one of the most pressing questions in modern cosmology, known as Hubble tension. "We know the expansion rate of the Universe with less error than traffic radars that catch us speeding," explains Licia Verde, ICREA researcher at ICCUB and coordinator of the RedH0T project, which was awarded 12 million euros and also includes the collaboration of Ad1 Ries 2.

The challenge lies in resolving the current discrepancy between the two techniques used to measure the expansion rate of the Universe. Despite being extremely precise individually, their results do not agree. RedH0T aims to determine whether this discrepancy stems from observational errors or limitations of the current cosmological model. "If we were to determine that the current model of the Universe is incorrect, it would be one of the most significant discoveries of the 21st century, with profound implications for fundamental physics," states Verde, adding that, "whatever the outcome, it will not be just any error, and it will allow us to learn a great deal."

The RedH0T project is expected to improve all current measurements of the Universe's expansion rate by cross-checking the Hubble constant (H0). This will yield results that will guide cosmologists in revising the current paradigm. "We want to lay the groundwork for the next Einstein," says Verde.

The RedH0T project will use an innovative data analysis methodology based on cybersecurity techniques employed by ethical hackers. The analysis will be carried out in collaboration with three distinct teams. A first "blue" team, made up of experts, will develop the methodology; a second "red" team, composed of specialists, will test the methodology and search for vulnerabilities; and a third "white" team will oversee the entire process. "We want each methodology to be validated with maximum transparency and rigor, fostering scientific consensus," says Fred Courbin, ICREA researcher at ICCUB and the Institut d'Estudis Espacials de Catalunya and co-leader of the project.

The Sun, so close and yet so unknown

The Sun generates its energy through nuclear fusion reactions. During this process, hydrogen atoms fuse together to form helium and generate the energy that makes the star shine. These fusion reactions can be described by a mathematical model known as the Standard Solar Model. However, this model, which not only explains how the Sun works but also describes other stars, is still very imprecise. "The internal structure of the Sun predicted by the models differs from observations," says Aldo Serenelli, director of the Institute of Space Sciences at the Spanish National Research Council (CSIC) and head of the LUNANOVA project in Spain, another of the projects awarded Synergy grants.

The solar model can be validated through observations using various sources of information, such as the neutrinos emitted by the star or the abundance of elements in its atmosphere. "The metals that make up stars determine their evolution," explains Serenelli, who adds that, "the current solar model is based on its head (the observations) and not its feet (the model itself), as it should be." To improve this model, the LUNANOVA project, with the participation of the Institute of Space Sciences, aims to enhance our fundamental understanding of nuclear physics. The Helmholtz Centre Dresden-Rossendorf in Germany, the Italian National Institute of Nuclear Physics, and the University of Naples Federico II are also collaborating on the project.

With a budget of 14 million euros, the project envisions the construction of a particle accelerator that will recreate conditions similar to those found in our star. This accelerator, to be installed beneath the Gran Sasso mountains in Italy to avoid cosmic radiation, will study the types of nuclear reactions that take place in the Sun, as well as their frequency. "Until we understand how these reactions work much better than we do today, it will be impossible to eliminate the uncertainties in the models," says Serenelli. The information provided by the LUNANOVA project, combined with data from other neutrino and dark matter detection experiments, will offer unprecedented insights into the processes occurring in all stars throughout the Universe.