The Solar System, as we know it today, was not always a flat, pancake-like structure. Scientists have recently discovered that the early formation of the Solar System was more toroidal, resembling a donut shape rather than a disk. This new insight was gained through the study of iron meteorites originating from the outer regions of the Solar System.
The process of a planetary system coming into existence around a star starts with a molecular cloud of gas and dust in space. When a portion of this cloud becomes dense enough, it collapses under its own gravitational force, forming a spinning baby star. As the star spins, the material surrounding it coalesces into a disk, feeding into the protostar. Within this disk, smaller clumps form, which eventually grow into planets or remain as smaller celestial objects like asteroids.
Iron meteorites found within our Solar System provide valuable clues about its early formation. These meteorites, rich in refractory metals such as platinum and iridium, suggest a hot environment close to a forming star. The presence of these metals in meteorites originating from the outer Solar System poses a challenge, as they must have formed closer to the Sun and then migrated outward as the protoplanetary disk expanded.
Research conducted by planetary scientist Bidong Zhang and his team at the University of California Los Angeles reveals that the composition of asteroids in the outer Solar System requires a toroidal shape rather than a flat disk. Modeling by the researchers suggests that iron meteorites from the outer Solar System could not have traversed gaps in a disk, indicating a toroidal structure that allowed these metal-rich objects to move towards the outer fringes of the forming Solar System.
The formation of Jupiter played a crucial role in the distribution of iridium and platinum metals in the early Solar System. Once Jupiter formed, it created a physical gap in the protoplanetary disk, trapping these metals in the outer regions of the disk and preventing them from falling into the Sun. This explains why meteorites originating from the outer disk have higher iridium and platinum contents compared to those from the inner disk.
Studying iron meteorites from the outer Solar System has provided valuable insights into the early formation and shape of our own Solar System. By understanding the processes that led to its current structure, we can gain a better understanding of planetary formation in general and apply this knowledge to interpret emerging planetary systems in other parts of the universe. The study of these celestial objects continues to shed light on the mysteries of our cosmic origins.
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