Precursor ingredients for life and water discovered in ancient alien salt crystals
A team of United Kingdom-based researchers discovered "life's precursor molecules" housed in extraterrestrial salt crystals collected from two ancient meteorites that date back to the formation of the solar system.
The millimeter-sized, sapphire- and purple-hued crystals of water-bearing halite came from the 4.5-billion-year-old Monahans and Zag meteorites, which plummeted to Earth in 1998.
The team of Open University researchers, led by postdoctoral research associate, Dr. Queenie Hoi Shan Chan, published their findings last month in Science Advances after a series of meticulous tests and extensive study.
"Organic matter has been studied for meteorites previously, but this is the very first analysis of organic compounds hosted within meteorites, and the tiny blue salt crystals that were also found to contain liquid water," lead author Dr. Chan said.
Blue halite crystal from Zag meteorite. (Photo/Dr. Queenie Hoi Shan Chan)
Due to a lack of technology in 1998 capable of achieving the level of comprehensive analysis the team undertook, the alien salt crystals had been awaiting future study in storage at NASA's Johnson Space Center.
"We carefully kept the meteorite samples at NASA JSC and only opened it up to subsample for the salt crystals when we determined that our technology was mature for studying the organic material inside of these crystals," Chan said.
The main challenges for the team were the tiny sample amount and keeping it free from terrestrial contamination, she added.
"We only had about 3 mg of halite crystals, as compared to the 100 mg typically used for amino acid analyses of meteorites."
According to the team's report, their findings included organic chemical compounds containing a mixture of carbon, oxygen and nitrogen bearing materials, which are precursors to amino acids.
"We have found a wide variety of organic compounds, but the molecules that are more correlated to life are amino acids, because amino acids are also the building blocks of proteins without which life would not be feasible," Chan said.
Finding amino acids, however, would still not indicate the existence of extraterrestrial life, because amino acids could also be produced by non-biological processes, she added.
Dr. Queenie Chan sits next to a spectrometer, one of the instruments used to study examine extraterrestrial salt crystals. (Photo/Dr. Queenie Hoi Shan Chan)
"Having said that, the extensive variety of organics hosted in the salt crystals suggests that the asteroid where the halite precipitated, contains a combination of precursor molecules for complex chemical reactions to occur," Chan said.
In addition to finding complex organic chemistry and liquid water in the crystals, the team also gained insight into the materials present in the earliest days of the solar system and the unique voyages of the two meteorites before they fell to Earth.
"The mineral compositions of the Monahans and Zag meteorites are very similar," Chan said.
Through the use of isotopic dating, the ages of the salt crystals were also determined to be consistent.
"The fact that they both contain blue crystals with water inclusion suggests that the meteorites come from the same asteroid parent body," she added.
Most of the rocky remnants from comets and asteroids entering Earth's atmosphere meet a fiery end and can be seen bursting into glowing streaks across the night sky.
Meteorites are the pieces of space debris that survive the harsh conditions of atmospheric entry and successfully make it to the surface, bringing with them celestial secrets from their long voyages across space and time.
By analyzing the mineral compositions of the Monahans and Zag meteorites, the research team was able to find differences in the origins of the salt crystals and the meteorites that carried them to Earth.
"We think that the water, the organic matter in the salt crystals and the salt crystals themselves came from a asteroid parent body, or a carbon rich asteroid, that is different from the asteroid which the Monahans and Zag meteorites are from," Chan said.
The finding would indicate an exchange of materials between two different asteroids, which collided long ago.
According to Chan, it is likely the water-bearing brine may have been synthesized during hydrovolcanic activity.
"The isotopic composition of the water also indicate a probable source of water from hydrovolcanism on the asteroid, potentially Ceres, the largest object in our asteroid belt," Chan said.
In their ongoing efforts, the team will attempt to locate more liquid water inclusions from the salt crystals, furthering their research with detailed chemical and isotopic analyses to identify its origins.
"We have saved several large blue salt crystals for future analyses," she said.
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