First Earth tomography with neutrinos
Researchers from the Institute of Corpuscular Physics (IFIC, CSIC-Universitat de València) and the University of Barcelona publish today in Nature Physics the first CT of the Earth in which they use neutrinos. This elementary particle, one of the most abundant in the Universe, is able to cross the planet without flinching, so it can provide valuable information about the distribution of its density, especially in little-known areas such as the inner core. Scientists have also used neutrinos for the first time to measure other properties of the Earth, such as its mass, and have obtained consistent results with traditional geophysical methods. The study uses data from the IceCube experiment, the largest neutrino telescope in the world located in Antarctica.
Researchers from the Institute of Corpuscular Physics (IFIC, CSIC-Universitat de València) and the University of Barcelona publish today in Nature Physics the first CT of the Earth in which they use neutrinos. This elementary particle, one of the most abundant in the Universe, is able to cross the planet without flinching, so it can provide valuable information about the distribution of its density, especially in little-known areas such as the inner core. Scientists have also used neutrinos for the first time to measure other properties of the Earth, such as its mass, and have obtained consistent results with traditional geophysical methods. The study uses data from the IceCube experiment, the largest neutrino telescope in the world located in Antarctica.
Neutrinos are the only known particles that can cross the Earth. This is possible because they hardly interact with ordinary matter, that which we see in the Universe and which builds our planet and ourselves up. That is why it is said that the neutrino is the 'phantom particle', and huge detectors are required to trap them. IceCube uses a cubic kilometre of ice from the South Pole to capture the neutrinos that have more energy, some of which come from the most extreme phenomena of the cosmos such as black holes or supernovas.
The neutrinos that have more energy are partially absorbed by the materials that make the Earth up, in an already established proportion by the international scientific collaboration that conducts the IceCube experiment. Now, the researchers of the Institute of Corpuscular Physics Andrea Donini, Sergio Palomares and Jordi Salvadó, currently at the Institute of Cosmetology Sciences of the University of Barcelona (ICCUB), have linked these absorption rates with approximately 20,000 high-energy neutrinos produced by the collision of cosmic rays in the atmosphere, known as atmospheric neutrinos, detected by IceCube in 2011. With these, they have conducted the first study of the density of the planet using this elementary particle.
Further information
Article reference:
Donini, A.; Palomares, S.; Salvadó, J. "Neutrino tomography of Earth", Nature Physics, 2018. Doi: https://doi.org/10.1038/s41567-018-0319-1