Asteroid rocks are beginning to reveal the origins of our solar system

Curtin University researchers are among a global team of scientists unraveling how our solar system came to be by unlocking the secrets hidden in a 4.5 billion-year-old asteroid.

In September of last year, after a seven-year journey, NASA’s billion-dollar OSIRIS-REx mission successfully returned samples from asteroid Bennu, with the samples sent to research labs around the world, including Curtin.

A new study published in Meteoritics and Planetary Science reveals the first findings from the samples – and there were a few surprises for the team.

The samples consisted mostly of dark particles ranging from dust size to approximately 3.5 cm long, however, there are some lighter particles scattered here, some with stones that also have lighter material forming veins and crusts.

OSIRIS-REx sample analysis team member Associate Professor Nick Timms, from the Curtin School of Earth and Planetary Sciences, said that unlike meteorites that fell to Earth, the material collected from Bennu was preserved in its original state and was not contaminated by the Earth’s atmosphere or biosphere. .

“The analyzes show that Bennu is among the most chemically primitive materials known, with a similar composition to the visible surface of the Sun,” Associate Professor Timms said.

“This means that Bennu went through different processes than the planets, and these processes changed the abundance of certain elements relative to the Sun.”

Analysis of the samples confirmed the presence of various components previously thought to be present, such as hydrated phyllosilicates (a type of mineral that forms in the presence of water) and carbon-rich material.

“This means that asteroids like this could have played a key role in supplying water and the building blocks of life on Earth,” Associate Professor Timms said.

The samples also contained several unexpected components.

“We were surprised to find magnesium and sodium phosphates, further suggesting that Bennu experienced a chemical environment that probably included water,” Associate Professor Timms said.

“We also found other trace minerals that offer clues to the processes that took place 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 insight into the early solar system and how the various planetary bodies in the solar system were formed.”

Associate Professor Timms said many more discoveries would be made from the Bennu samples, which would have a wide range of implications for understanding the early solar system.

“The sample contains pre-solar grains formed 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 for understanding the composition of asteroids, from identifying potential mining opportunities to knowing how best to protect yourself should an asteroid be on a collision course with Earth.”