The rocky planets of the inner Solar System (Mercury, Venus, Earth and Mars) were formed half a million years before the rest, according to a study carried out by scientists from the Federal Polytechnic School of Zurich (EPFZ) and other European institutions.
The research, in which German and British scholars also collaborate, affirms that the first elements of these four inner planets were formed 4.5 billion years ago, when the Solar System was nothing more than a disk of gas and dust.
According to the study, this gas disk contained a radioactive isotope, aluminum-26, which heated the planets from within to form water, lava and steam.
Half a million years later, thanks to the fact that this isotope had disappeared, the gas and ice giants of the outer Solar System were formed: Jupiter, Saturn, Uranus and Neptune.
“Their formation began later, but it was much faster than that of the inner planets“said the Oxford University researcher leading the study Tim lichtenberg, who explained that the last planets grew to their current size as a result of collisions and accumulations of dust.
According to the EPFZ, planet Earth later received additional water from the outer Solar System, thanks to the gravitational pull of Jupiter.