In October 2020, a van-sized robotic spacecraft briefly touched down on the floor of Bennu, a 525-metre-wide asteroid 320 million kilometres from Earth.
As a part of NASA’s OSIRIS-REx mission, the spacecraft not solely spent two years orbiting and imaging the asteroid, it additionally collected a valuable pattern of mud and small rocks from Bennu’s rubbly floor.
In September 2023, a capsule containing the pristine asteroid pattern returned to Earth, touchdown within the Utah desert in the USA.
Since then, a world staff of scientists – of which we’re members – have been busy learning the roughly 120 grams of fabric collected from Bennu.
Our findings are revealed in two new papers revealed in Nature and Nature Astronomy in the present day. They point out that water might have as soon as been current on Bennu’s guardian physique, and supply new insights into the chemistry of the early Photo voltaic System.
allowfullscreen=”allowfullscreen” frameborder=”0″>
Pristine remnants of rocks from deep time
Asteroids are fragmentary remnants of pre-existing guardian our bodies from early in our Photo voltaic System’s historical past which have since been destroyed by collisions with different objects. They orbit the Solar and are available many various shapes, sizes and chemical compositions.
Asteroid Bennu was focused for the OSIRIS-REx mission as a result of distant sensing observations from Earth indicated it as a B-type asteroid.
These asteroids are wealthy in carbon and hydrated clay minerals, presumably sharing similarities to probably the most primitive group of meteorites on Earth, referred to as carbonaceous chondrites.
Not like meteorite samples, samples collected from asteroids haven’t been bodily or chemically modified by Earth’s ambiance and biosphere. This permits us to deal with key questions in regards to the evolution of the early Photo voltaic System, planet formation, and the elements for all times.
One other purpose of the OSIRIS-REx mission is to hyperlink findings from samples within the laboratory to these from distant sensing methods. This helps us corroborate astronomical observations of asteroids to enhance our surveys of the Photo voltaic System.
Tiny crystals of salt minerals
To stop contamination, the sealed capsule containing the pattern was saved and dealt with in an enormous glass field when it was returned to Earth.
This tank had rubber gloves feeding into it from the aspect so scientists may deal with the samples with out instantly touching them. It had additionally been purged with nitrogen to maintain out moisture and oxygen from Earth’s ambiance.
After we analysed the inside of Bennu’s mud particles, we have been stunned to search out tiny crystals of the salt minerals referred to as halite and sylvite.
This was a breakthrough discovery.
frameborder=”0″ allow=”accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen>
Halite is extraordinarily uncommon in meteorites. It has solely been present in three out of lots of of hundreds of identified meteorites on Earth. We additionally know that halite is very soluble. It might probably degrade shortly when uncovered to air or water on Earth.
Different members of the OSIRIS-REx pattern evaluation staff recognized a wide range of different salt minerals within the Bennu pattern. These included sodium carbonates, phosphates, sulphates and fluorides.
These minerals can kind by the evaporation of brines – much like deposits that kind in Earth’s salt lakes.
By evaluating these outcomes with the chemical make-up of salt lakes on Earth, an image started to emerge of brines evaporating on the guardian physique of asteroid Bennu, forsaking salts as proof.
A wide range of natural compounds
This discovery supplies a brand new perception into water exercise throughout the earliest occasions in our Photo voltaic System. However the presence of salt minerals is important for an additional motive.
On Earth, these minerals are a catalyst for the formation of natural compounds reminiscent of nucleobases and nucleosides – the prebiotic constructing blocks of terrestrial biology.
And certainly, in a separate evaluation of the Bennu pattern, different colleagues on the OSIRIS-REx mission recognized all kinds of natural compounds current on the carbon- and nitrogen-rich asteroid.
These compounds embody 14 of the 20 amino acids we additionally discover in Earth’s organic processes. Additionally they embody a number of amino acids which can be absent in identified biology, ammonia, and all 5 nucleobases present in RNA and DNA.
Regardless that no life was detected on Bennu, the 2 new research present {that a} briny, carbon-rich atmosphere on Bennu’s guardian physique was appropriate for assembling the constructing blocks of life.
Ongoing investigations
The findings from returned samples of asteroid Bennu might present researchers perception into what occurs on distant icy our bodies in our Photo voltaic System.
A few of these our bodies embody Saturn‘s moon Enceladus and the dwarf planet Ceres within the asteroid belt between Mars and Jupiter.
Each Enceladus and Ceres have subsurface brine oceans. Might they presumably harbour life?
We’re persevering with to analyze Bennu utilizing the pristine samples collected again in 2020. We’re presently researching the timing of the Bennu guardian physique breakup occasion and searching for proof of impacts recorded by numerous minerals within the samples.
The authors of this text acknowledge the contribution of the next individuals to the analysis at Curtin College: Fred Jourdan, Steven Reddy, David Saxey, Celia Mayers, and Xiao Solar, in addition to your complete OSIRIS-REx staff.
Nick Timms, Affiliate Professor, College of Earth and Planetary Sciences, Curtin College; Phil Bland, Director, Binar Area Program, Curtin College, and William Rickard, Affiliate Professor, School of Science and Engineering, Curtin College
This text is republished from The Dialog below a Artistic Commons license. Learn the authentic article.
