Billions of years ago, Mars was hypothesized to have been a habitable world with flowing liquid water and the potential for life.
But directly studying its ancient past is currently limited to orbiters and rovers, as scientists have yet to obtain direct samples from Mars.
However, meteorites have been found on Earth to have potentially originated from Mars during large impacts that flung chunks of the Red Planet into space, eventually being grabbed by Earth’s gravity and crashing into the Earth’s surface.
Now, an international team of scientists might be one step closer to piecing together Mars’ watery ancient past, and specifically how much water could have flowed across the Red Planet’s surface long ago.
In findings recently published in the Geophysical Research Letters, a collaborative team of researchers led by the Technical University of Denmark investigated an intriguing meteorite with an even more intriguing name, “Black Beauty”, with the scientific designation of Northwest Africa 7034 (NWA 7034).
What makes Black Beauty so intriguing is its designation as the only known meteorite that originated from the crust of Mars, having been blasted away during an impact billions of years ago, as Black Beauty is estimated to be about 4.4 to 4.5 billion years old.
Using a combination of X-ray and neutron tomography, the researchers analyzed Black Beauty with the goal of ascertaining if the ancient meteorite contained traces of water, also called hydrous materials in the scientific community.
While X-ray tomography is used to identify the densest parts of Black Beauty while focusing on iron and silicon, neutron tomography was used to identify that previous “holes” found by normal X-rays were actually hydrous materials.
“Neutrons are particularly sensitive to hydrogen,” said Dr. David Mannes, who is a scientist at the Paul Scherrer Institute (PSI), a co-author on the study. Dr. Mannes collaborated with fellow study co-author, Dr. Anders Kaestner, on the neutron tomography at PSI. “In combination with X-ray tomography, we were not only able to detect tiny hydrated minerals, but also, for the first time, visualize larger, macroscopic hydrogen deposits.”
Essentially, the researchers identified that early Mars contained a water reservoir large enough to engage with the Martian surface and crust, resulting in water deposits into crustal rocks that eventually became Black Beauty. The researchers also note these materials are similar to materials found in Jezero Crater by NASA’s Perseverance rover. Therefore, Black Beauty continues to add a growing pile of evidence that Mars was a much warmer and wetter planet billions of years ago.
While Black Beauty has revealed intricate details regarding ancient Mars and its watery past, arguably the most famous meteorite from Mars is the Allan Hills 84001 (ALH84001) meteorite, which was recovered in Antarctica on December 27, 1984. However, it wasn’t until 1996 before scientists discovered it was potentially from Mars, as ALH84001 had initially been designated as an asteroid chunk, which are frequently discovered on Earth. Once scientists studied ALH84001, they discovered it contained unique structures they hypothesized could indicate signs of ancient Martian life.
While their 1996 study published in Science gained worldwide attention, including an official address from President Bill Clinton, the scientific community was quick to claim these features could have formed from non-biological processes. Regardless of its specific origin, both Black Beauty and ALH84001 demonstrate the importance of bringing back samples from Mars to reduce relying on ancient meteorites.
Unfortunately, the long-anticipated NASA-ESA Mars Sample Return mission was canceled by Congress due to ballooning costs, meaning all the sample tubes that NASA’s Perseverance rover has been depositing on the Martian surface is potentially for nought. For now, scientists have to rely on meteorites to unlock the secrets of ancient Mars, but China’s planned Tianwen-3 might be the first to return Mars samples to Earth sometime next decade.
What new insights into the “Black Beauty” meteorite and ancient Mars will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Written by Laurence Tognetti, MSc/Universe Today.
