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Asteroid Bennu holds secrets of the solar system's past

Have you ever wondered about the origins of our solar system? How did this cosmic structure that we call home come to be? The answers, it seems, may lie in an object that’s been soaring through space for over 4.5 billion years – the asteroid Bennu.

Scientists from Curtin University, among a global team, have been laboring to uncover these cosmic secrets. Their investigation has led them on a celestial detective journey, looking at the ancient bits of cosmic rocks like breadcrumbs leading to the very beginnings of our existence.

Clues from Bennu

Professor Nick Timms, from Curtin’s School of Earth and Planetary Sciences and a member of OSIRIS-REx Sample Analysis Team, shared some of the preliminary findings from this asteroid investigation.

The samples were brought back to Earth last September by NASA’s billion-dollar OSIRIS-REx mission. The expedition, seven years in the making, successfully collected asteroid samples that were then dispatched to research laboratories worldwide, including Curtin University.

What secrets does Bennu hold?

The samples from Bennu consisted mostly of dark particles, some lighter ones scattered among them.

These multi-faceted particles, ranging from dust-sized to approximately 3.5 cm long, held a wealth of surprises. Unlike meteorites that have fallen to Earth, these samples have been preserved in their pristine condition, untouched by Earth’s atmosphere or biosphere.

“Bennu is among the most chemically primitive materials known, similar in composition to the visible surface of the sun,” noted Professor Timms. The asteroid had undergone separate processes to the planets, altering the abundance of specific elements relative to the sun.

A cosmic delivery service

Analyses confirmed the presence of various components previously suspected to exist, such as hydrated phyllosilicates (a type of mineral that forms in the presence of water) and carbon-rich material.

“This suggests asteroids like Bennu might have been key players in delivering water and life’s building blocks to Earth,” explained Professor Timms.

These findings provide valuable insights into the processes that may have contributed to the emergence of life on our planet and underscore the importance of continued space exploration and research.

Unexpected findings

The cosmic breadcrumbs also contained several unforeseen components. “We were surprised to find magnesium-sodium phosphates, which further suggests Bennu experienced chemical environments which possibly involved water,” said Professor Timms.

“We also found other trace minerals, which offer clues as to the processes which have happened on Bennu over billions of years, such as temperature and pressure conditions.”

“These trace minerals help paint a picture of Bennu’s evolution and also offer insights into the early solar system and how the different planetary bodies in the solar system were created.”

Practical implications of the discovery

These tiny samples don’t just reveal secrets about our cosmic beginnings but also pose practical implications.

“The sample has presolar grains created before our solar system existed, which can provide a detailed biography of the lives of ancient stars,” said Professor Timms.

“There are also very practical implications to understanding the composition of asteroids, from identifying potential mining opportunities to knowing how to best protect ourselves should an asteroid be on a collision course with Earth.”

The ongoing analysis of Bennu will continue to uncover even more secrets, shedding light on the lives of ancient stars and offering fresh perspectives on our early solar system. Only time will tell where this cosmic detective story will lead us.

Future missions and expectations

The OSIRIS-REx mission has set a high benchmark for upcoming space ventures.

Future missions will likely build upon its success, including NASA’s mission to the asteroid Psyche, expected to launch in 2023, and Japan’s Hayabusa2 mission that has already returned samples from asteroid Ryugu.

These efforts aim to construct a comprehensive map of our solar system’s building blocks, piecing together the intricate mosaic of cosmic evolution.

As technology advances, the ability to capture and analyze extraterrestrial materials will continue to improve, revealing more about the age-old mysteries of the universe.

The study is published in arXiv.


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