Much has changed in the approximately 4.5 billion years since the Solar System formed from a disc-like cloud of swirling dust and gas. The matter from which everything is composed has undergone serious changes; squeezed into planets, blasted by solar radiation and plasma, changed by interacting with other atoms. Therefore, it is difficult to distinguish the main components of this first dust disk. However, as can be seen, this is not completely impossible.

An international team of scientists has discovered traces of material preserved inside an ancient rock that fell to Earth from space and was found in 2018; They say it must have originated from a proto-planetary disk when the solar system was young. It’s a discovery that could give us new insight into the history of the Solar System and the fundamental building blocks from which everything around us, here on Earth and around the Sun, was born a long time ago.

The sun, like all stars, was born in a cloud of dust. The denser knot in the cloud collapsed under its own gravity, spinning and collapsing the material around it into a disk that fed into the growing star. When the Sun ended, what was left of that disk formed everything else in the Solar System: planets, moons, asteroids, comets, and the icy rocks that make up the global Oort Cloud, which is thought to encompass everything.

This Oort Cloud consists of chunks of icy rock that sometimes fall into the interior of the Solar System as it orbits the Sun, spewing out gas and dust. These are long-period comets with orbits of hundreds to hundreds of thousands of years. Located so far from the Sun, the Oort Cloud is thought to have remained relatively unchanged since the birth of the Solar System and is therefore the most pristine example of the primitive material that forms the disk from which planets form.

However, this material was difficult to examine carefully. Comet fragments containing this primitive material melt as they fall, even as they make the long journey through the solar system to enter Earth’s atmosphere.

This brings us to meteors. Although space is mostly empty, comets and meteors occasionally collide. When this happens, it’s possible for comet material to mix with the meteorite and become trapped inside in pieces called debris.

If this meteorite enters the Earth’s atmosphere, it will also be heated, but the comet debris inside may remain preserved and reach the surface intact. A research team led by cosmochemist Elisheva van Kooten of the University of Copenhagen found it in a meteorite called Northwest Africa 14250 (NWA 14250).

Using scanning electron microscopy and spectroscopic analysis, the researchers examined the composition of NWA 14250 very closely and the isotopes of various minerals found within it. The researchers determined that the minerals in some of the clasts were likely of comet origin; This means meteorites like NWA 14250 could be a tool for studying the composition of the early Solar System.

But there is something else. The team found that the fragments were very familiar: They resembled fragments found in other meteorites in the outer solar system near Neptune and samples taken from the asteroid Ryugu. The researchers say this suggests that not only was the primordial material relatively common (albeit elusive) but also that the composition of the protoplanetary disk was relatively uniform during the formation of the Solar System.

“Contrary to popular belief, the isotope signature of the comet-forming region is ubiquitous among outer Solar System bodies and likely reflects an important planetary building block in the outer Solar System,” the researchers write. “This makes it possible to determine the nucleosynthetic fingerprint of the comet-forming region and thereby reveal the accretion history of the solar protoplanetary disk.” The study was published on: Science Developments.