Researchers at Curtin University, along with a global team of scientists, are delving into the origins of our solar system by uncovering the secrets held within a 4.5-billion-year-old asteroid.
In September of last year, samples from the asteroid Bennu were successfully brought back by NASA’s billion-dollar OSIRIS-REx mission after a seven-year journey. These samples have been distributed to research laboratories worldwide, including Curtin.
The initial findings from the samples have been unveiled in a new study published in Meteoritics and Planetary Science, and they have brought some unexpected discoveries for the team.
The collected samples mainly consisted of dark particles in sizes ranging from dust-sized to about 3.5 cm long. However, there are also some lighter particles mixed in, and some stones contain brighter material, forming veins and crusts.
According to Associate Professor Nick Timms from Curtin’s School of Earth and Planetary Sciences, the material gathered from Bennu remains in pristine condition as it has not been contaminated by Earth’s atmosphere or biosphere, unlike meteorites that have fallen to Earth.
“Analyses show Bennu is among the most chemically primitive materials known, similar in composition to the visible surface of the sun,” Associate Professor Timms said. “This indicates Bennu has undergone different processes to the planets, and these processes changed the abundance of particular elements relative to the sun.”
The presence of different components, including hydrated phyllosilicates (a type of mineral which forms in the presence of water) and carbon-rich material, was confirmed in the analysis of the samples.
“This means asteroids such as this may have played a key role in delivering water and the building blocks of life to Earth,” Associate Professor Timms said.
Additionally, the samples revealed the existence of several unexpected components.
“We were surprised to find magnesium-sodium phosphates, which further suggests Bennu experienced chemical environments that possibly involved water,” Associate Professor Timms said. “We also found other trace minerals, which offer clues as to the processes that 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.”
Associate Professor Timms stated that the Bennu samples will lead to numerous new discoveries and have far-reaching implications for our understanding of the early solar system.
“The sample has presolar grains created before our solar system existed, which can provide a detailed biography of the lives of ancient stars,” Associate Professor Timms said. “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.”
Journal reference:
- Dante S. Lauretta et al. Asteroid (101955) Bennu in the laboratory: Properties of the sample collected by OSIRIS-REx. Meteoritics and Planetary Science, 2024; DOI: 10.1111/maps.14227