Nature Astronomy: CU scientists analysed a meteorite and contributed to research crucial for planetary defence
Asteroid 2023 CX1 belongs to the small group of celestial bodies that have been detected before entering Earth’s atmosphere. By analysing fragments of the recovered meteorite, nuclear physicists from the Faculty of Mathematics, Physics and Informatics of Comenius University Bratislava (FMPI CU) contributed to research that began with the asteroid’s orbital tracking in space and culminated in laboratory analyses of its remnants found on Earth. The results of their work reached the international scientific community through publication in the prestigious journal Nature Astronomy.
Among the leading Slovak experts involved in the research were Professor Pavel Povinec, Assoc. Professor Ivan Sýkora, and Dr Ivan Kontuľ from the Department of Nuclear Physics and Biophysics of FMPI CU. The Slovak team analysed terrestrial fragments of the asteroid, known as the Saint-Pierre-le-Viger (SPLV) meteorite, using gamma spectrometry to determine the concentrations of cosmogenic radionuclides, i.e. radioactive isotopes produced by the interaction of cosmic rays with the asteroid during its journey through space. These radionuclides provide data on how long the asteroid was exposed to cosmic radiation and help ascertain its pre-atmospheric size.
When such an object passes through Earth’s atmosphere, its surviving solid pieces are called meteorites. Analyses of these meteorites enabled Slovak researchers to determine that the pre-atmospheric diameter of the body was about 72 centimetres and its mass approximately 650 kilograms, as well as its cosmic-ray exposure age - the time elapsed since the asteroid was ejected from its parent body - about 30 million years ago within the inner main asteroid belt between Mars and Jupiter. “We received the fragments for analysis only two weeks after the fall, which allowed us to determine key parameters such as its age, size and mass,” explains Dr Kontuľ.
Astronomers observed the fall itself as a bright fireball over Normandy, and thanks to the predicted trajectory, fragments were quickly located by both professional and amateur observers. Nearly one hundred fragments were eventually recovered. “The case of 2023 CX1 is unique in that such objects usually fragment gradually in the upper atmosphere, but this one disintegrated suddenly at an altitude of about 28 kilometres,” Kontuľ notes. “It lost 98 percent of its energy within a fraction of a second, producing a strong spherical shock wave. This behaviour has major implications for planetary defence, as such abrupt disruption could cause greater damage if the explosion occurred lower above the ground. It highlights the importance of these findings for future planetary protection strategies.”
In their meteorite study, researchers from FMPI CU closely cooperate with astronomers and other specialists from European and overseas institutions engaged in mineralogy, chemical-composition analysis, and optical and seismo-acoustic observations. Tracking asteroids of this kind holds exceptional importance for the academic community as well. “It was fascinating to hold in my hand something that had been flying through space just two weeks earlier - it's an experience one does not have every day,” Dr Kontuľ concludes.
The international research team, led by astrophysicist Auriane Egal from the University of Western Ontario, Canada, monitored the asteroid comprehensively - from its discovery in Hungary less than seven hours before impact to laboratory analyses of fragments collected in Normandy. This unprecedented collaboration sets a new standard for asteroid and meteorite research and enhances our understanding of how to protect Earth from extraterrestrial threats. The results of the team’s work were recently published in the international scientific journal Nature Astronomy.
A. Egal et al.: Catastrophic disruption of asteroid 2023 CX1 and implications for planetary defence. Nature Astronomy (2025). DOI: 10.1038/s41550-025-02659-8