scientists have revealed that Nasa's mission to the asteroid Vesta has raised fundamental questions about planet formation, including our planet Earth.
EPFL researchers have concluded from the data that the asteroid's crust is almost three times thicker than expected, while challenging a fundamental component in planet formation models, namely the composition of the original cloud of matter that aggregated together, heated, melted and then crystallized to form planets.
The researchers said that they find it striking that there is an absence of a particular mineral, olivine, on the asteroid's surface and olivine is a main component of planetary mantles and should have been found in large quantities on the surface of Vesta, due to a double meteorite impact that, according to computer simulations, "dug" the celestial body's southern pole to a depth of 80 km, catapulting large amounts of materials to the surface.
The scientists said that The two impacts were so powerful that more than 5% of Earth's meteorites come from Vesta, but these cataclysms were not strong enough to pierce through the crust and reach the asteroid's mantle.
The meteorites originating from Vesta and found on Earth confirm this since they generally lack Olivine, or contain only minute amounts compared to the amount observed in planetary mantles. Also, the spacecraft Dawn did not find olivine in the vicinity of the two impact craters.
The study suggests that a more complex model of planet formation therefore has to be considered, one that takes into account not only the original composition of planets, but also their orbits, sizes and related cooling times.
The study was published in Nature.
