Asteroid rocks begin to reveal the origins of our solar system

Curtin University researchers are among a global team of scientists unraveling how our solar system was born, uncovering secrets hidden inside 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 the asteroid Bennu, with specimens sent to research laboratories around the world, including Curtin.

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

The samples consisted of mostly dark particles ranging from dust size to approximately 3.5 cm long, however there are some lighter particles scattered throughout, some with stones also having brighter material forming veins and crust.

OSIRIS-REx sample analysis team member Associate Professor Nick Timms from the Curtin School of Earth and Planetary Sciences said that unlike meteorites that have fallen to Earth, the material collected from Bennu has been kept in a pristine state and is not contaminated by the Earth’s atmosphere or biosphere. .

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

“This shows that Bennu underwent different processes on the planet, and these processes changed the abundance of particular 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 materials.

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

The samples also contained some unexpected components.

“We were surprised to find magnesium-sodium phosphates, which further suggests that Bennu had experienced chemical environments, which probably included water,” Associate Professor Timms said.

“We also found other trace minerals, which provide 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 provide insights into the early solar system and how the various planetary bodies in the solar system formed.”

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

“The sample has presolar 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 defend ourselves if an asteroid is on a collision course with Earth.”