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Researchers study asteroid samples and reveal secrets about the early Solar System, shedding light on cosmic events that occurred billions of years ago
Scientists have analyzed grains from the asteroid Ryugu and discovered evidence of a magnetic field that may have influenced the formation of the outer solar system.
The discovery provides clues about how gas giants like Jupiter and Neptune formed. The study, published in the journal AGU Advances, involved researchers from MIT, Caltech and Harvard.
Asteroid as a time capsule
The asteroid Ryugu is a primitive celestial body that originated in the outer reaches of the solar system before being captured in the asteroid belt between Mars and Earth. In 2020, Japan's Hayabusa2 mission brought samples of this asteroid to study.
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Scientists expected these grains to contain information about the early conditions of the solar system.
The team looked for signs of ancient magnetic fields to understand whether a nebular field existed beyond 7 astronomical units (AU) from the Sun. This region is where massive gas planets formed.
Traces of magnetism in the outer solar system
Previous research suggests that the inner solar system had a strong magnetic field, influencing the formation of planets such as Earth, Venus and Mars. However, it was unclear whether this effect extended to the outer solar system.
Using a magnetometer, scientists analyzed Ryugu’s grains to reconstruct its magnetic history. They found that if a magnetic field existed in the region where the giant planets formed, it was weak — estimated at up to 15 microtesla. For comparison, Earth’s magnetic field today is about 50 microtesla.
According to Elias Mansbach, lead author of the study, this nebular magnetic field disappeared between 3 and 4 million years after the formation of the solar system. Even though it was weak, it may have been enough to attract gases and dust, contributing to the formation of planets like Jupiter and Saturn.
"This nebular field disappeared about 3 to 4 million years after the formation of the solar system, and we are fascinated by how it played a role in early planetary formation.“, said Mansbach.
Comparing with other meteorites
The team also compared the Ryugu data with that of other meteorites that formed in the outer solar system. One of them, classified as an unclustered carbonaceous chondrite, had a magnetic field of about 5 microtesla.
This similarity suggests that even the most distant regions of the solar nebula had some magnetic influence.
Benjamin Weiss, a planetary scientist at MIT and co-author of the study, highlighted the importance of this discovery: “We're showing that everywhere we look now, there was some kind of magnetic field that was responsible for bringing mass to where the sun and planets were forming.. "
The discovery challenges long-standing models that suggested there was no significant magnetic activity in the outer solar system. The data suggest that even in regions far from the Sun, a magnetic field helped shape the formation of gas planets.
Scientists plan to continue analyzing Ryugu's data and compare it with other space samples. This information could help them better understand how the solar system was organized in its first few million years.
With information from Daily Galaxy.
