A new study published in the journal Nature Astronomy appears to have confirmed that 6% of the Earth’s mass was carried by asteroids from the outer solar system. All this thanks to the samples of materials collected by the Hayabusa-2 probe on the asteroid Ryugu.
A few grams of soil from the surface and subsoil of the space stone they revealed new information about the past of our planet and the entire solar system. Scientists, in particular, analyzed the isotopic signatures of zinc and copper. Each chemical element comes in multiple versions depending on the number of neutrons in its nucleus.
This does not change the chemical properties of the material, but the physical ones since the isotopes have different masses. Some isotopes are not stable and decay after a while. This isotope ratio goes like this a chemical fingerprint for the materials and, among other things, it also tells us how these objects were formed.
In this study the team confirmed that the isotopic signature of copper and zinc makes it similar to the Ivuna meteorite, which fell in Tanzania on December 16, 1938 and is part of the CI group of carbonaceous chondrites formed in the outer solar system and eventually migrated inward. Asteroids that formed closer to the Sun have a different value than Ryugu.
With this in mind, the researchers were able to estimate what a Ryugu-like asteroid must have contributed about six percent to the land mass.