A grapefruit-sized fireball from the mysterious Oort Cloud could rewrite the history of the solar system
A dazzling fireball that has finished its cosmic journey over central Alberta, Canada could change astronomers’ understanding of how the solar system formed 4.5 billion years ago.
Captured on camera on February 22, 2021, the stony, grapefruit-sized meteorite is believed to have come from the Oort Cloud, a reservoir of celestial bodies that surrounds and separates the entire solar system from interstellar space. Scientists have never directly observed the rocky bodies in the Oort Cloud and have long believed that they contain only icy bodies. But the rocky body that burned up over Canada challenges popular theories about the formation of the Oort Cloud, and the formation of the early solar system in general, according to a study published Dec. 12 in the journal Solar System. natural astronomy (Opens in a new tab).
“This discovery supports a completely different model for the formation of the solar system, one that supports the idea that large amounts of rocky material coexist with icy bodies within the Oort Cloud,” says the study’s lead author. Denise Livesaid a postdoctoral researcher in meteorite physics at Western University in London, Ontario, Canada, in a statement. “This result is not explained by currently favored solar system formation models. It’s a complete game changer.”
According to NASAThe Oort Cloud is thought to have formed when gravity from newly formed planets pushed icy bodies away from the sun. gravity from Milky Way The galaxy has caused objects to settle at the edge of the solar system instead.
The current popular theory of how the solar system formed is Gallstone accumulation The model, which describes millimeter-sized pebbles that are sucked together over time to form celestial bodies.
“These findings challenge models of solar system formation that rely on accretion of gravel alone, which currently cannot be explained by the observed high abundance of rocky material in the Oort Cloud as derived from fireball measurements and telescopic data,” the authors write in the new study.
Instead, these findings support what is known as the “Grand Tack” theory of solar system formation. This model suggests that Jupiter formed near the Sun and migrated toward it before the gravitational effects of Jupiter and Saturn pushed both planets apart. Only this model can explain enough rocky material from the inner solar system that is ejected into the Oort cloud to explain the fireball, according to the researchers.
Fireball has been caught before Global Fireball Observatory (GFO) operated by the University of Alberta. The regional office is a global collaboration between organizations including the Lunar and Planetary Institute, NASA’s Goddard Space Flight Center, and several universities. His goal is to shoot fireballs so that the meteorites can be recovered.
Calculations of the fireball’s trajectory show that it traveled from the outer reaches of the solar system, similar to the trajectories of icy comets – the objects thought to inhabit the Oort Cloud. The rocky nature of the fireball is confirmed by its descent deeper into Earth’s atmosphere than icy bodies traveling in a similar orbit can survive. Then it also shattered, just as a normal rock fireball would.
However, the Alberta fireball is not a one-off. Researchers found a similar fireball in a historical database that had never been observed at the time. These multiple rocky bodies, the authors said, indicate that between 1% and 20% of the meteorites coming from the Oort Cloud are rocky.
“The better we understand the conditions in which the solar system was formed, the better we will understand what is necessary to ignite life,” said Veda. “We want to paint a picture, as accurately as possible, of these early moments in the solar system that were so crucial to everything that happened after that.”
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