New tools unlock new discoveries in science. So when a new type of non-destructive technology becomes widely available, it's inevitable that planetary scientists will get their hands on it to test it on some meteorites. A new paper, available in pre-print on arXiv, by Estrid Naver of the Technical University of Denmark and her co-authors, describes the use of two of those (relatively) new tools to one of the most famous meteorites in the world - NWA 7034 - also known as Black Beauty.
Part of Black Beauty’s fame comes from its origin. It’s a piece of Mars that fell to Earth, most likely after a huge impact on the Red Planet. It's made up of material from around 4.48 billion years ago, making it some of the oldest known Martian material in the solar system. Not to mention it’s strikingly beautiful - hence its name.
Unfortunately, previous studies have required scientists to cut off parts of this masterpiece in order to study them. These parts are then either crushed or dissolved to unlock the materials the rock is made up of. But we can do better than that now - with the advent of computed tomography (CT) machines.
https://www.youtube.com/shorts/nPJdZvHFuow Video of the CT scan of the Black Beauty meteorite. Credit - rebekahhines4431 YouTube Channel
There are two types of CT scanners. One, which is commonly used in doctor’s offices throughout the world, is X-ray CTs. These are exceptionally good at finding heavy, dense materials like iron or titanium. Another, less commonly used method, is Neutron CT, which uses neutrons instead of X-rays to pass through its object of study. The results from this scan vary widely, but it generally is better at penetrating denser materials, and, importantly, finding hydrogen - one of the key components of water.
In the paper, the researchers use both these techniques to non-destructively test Black Beauty and see what it held. While non-destructive, they did, admittedly, use only a small sample of the meteorite, which had been previously polished. But when they looked at their small sample material, they found “clasts”.
In geology terms, a clast is just a word for a small rock fragment stuck inside a bigger rock. Finding clasts isn’t surprising - scientists have known that Black Beauty was composed of them for decades, which makes sense given that we knew the origin of the meteorite was a Martian impact that fused rocks together. But the particular kinds of clasts that the CTs found were new.
Fraser discusses where liquid water could be hiding on Mars.Known as “Hydrogen-rich Iron oxyhydroxide”, or H-Fe-ox, clasts, these hydrogen-rich clusters made up approximately 0.4% of the volume of the sample of Black Beauty they tested, which was about the size of a fingernail. While that might seem like a small amount, the chemical math of the internal of the meteorite means that those little bits of rock hold up to about 11% of the sample’s total water content.
Black Beauty itself has an estimated 6,000 parts-per-million (ppm) of water, which is extremely high coming from a planet with so little water on it currently. But, importantly, these findings complement the discovery of watery samples at Jezero crater by Perseverance. Despite Black Beauty coming from a completely different part of Mars than the rover samples, the link between the samples proves there was widespread, likely liquid water, on the surface of Mars billions of years ago.
This beautiful meteorite is in itself basically a sample return mission in a single rock. However, the scientists that analyzed it were hoping to use the same non-destructive CT techniques on future Mars Sample Return mission samples. CT scans can see right through the titanium housing the samples had been collected in. But, given the recent cancellation of that program, it might be a very long time before any such direct planetary samples are subjected to the powerful tools we have back here on Earth.
There is still a Chinese sample return mission planned, though, so perhaps it won’t be as long as expected. Until then, running the same sort of non-destructive test on other Martian meteorites seems a good use of the expertise and equipment. Hopefully we’ll see plenty more studies of other samples in the future.
