An international group of scientists has discovered that Jupiter is the oldest of the planets in the Solar System. As if this were not enough, the examination of some isotopes present in meteorites suggests that this gas giant is older than the Sun itself; that is, it was formed before the Sun. The discovery has been published in the journal Proceedings of The National Academy of Sciences (PNAS).
To reach this conclusion, experts from the Lawrence Livermore National Laboratory (USA) and the Institut für Planetologie of the University of Münster (Germany), observed the concentrations of tungsten and molybdenum isotopes in ferrous meteorites , discovering that Meteorites were made up of two genetically distinct nebular deposits that coexisted but did not mix during the first million years after the formation of the solar system.
According to experts, the most admissible explanation for this separation is the formation of Jupiter between the two deposits. “Jupiter is the oldest planet in the solar system, and its solid core formed long before the solar nebula dissipated, consistent with the core accretion model for the formation of the giant planet,” explains Thomas Kruijer, leader of the work. .
Why is this discovery important?
Jupiter is the most massive planet in the solar system and its presence had an immense effect on the dynamics of the solar accretion disk. Knowing how Jupiter arose is key to understanding how the solar system evolved towards its current architecture. Although models predict that Jupiter formed relatively early, its formation had never been dated until now.
“ We do not have samples of Jupiter (in contrast to other bodies such as Earth, Mars, the Moon and asteroids). In our study, we used the isotopic signatures of meteorites (which are derived from asteroids) to infer the age of Jupiter”, Kruijer comments.
Thus, thanks to the analysis of meteorite isotopes, the experts showed that the solid core of Jupiter was formed only a million years after the beginning of the history of our solar system, making it the oldest planet of all (the Sun barely was a protostar at the time). Jupiter’s core grew by about 20 Earth masses in the first million years , followed by a longer growth of up to 50 Earth masses up to 3-4 million years after the solar system had formed.
Reference: Thomas S. Kruijer et al. Age of Jupiter inferred from the distinct genetics and formation times of meteorites, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073 / pnas.1704461114
Image credit: Lawrence Livermore National Laboratory
