4.6 billion-year-old Winchcombe meteorite contains the building blocks of life

The Winchcombe meteorite is a rare carbon-rich chondritic meteorite, meaning it is made up of up to 3.5 weight percent of carbon — only 4 percent of all recovered meteorites are this type.

There are reportedly more than 1,000 eyewitness accounts of it falling to Earth, and footage of the fireball is widely circulated online. Thankfully for the scientists who were tasked with analyzing the roughly 1lb (0.5kg) space rock, it was retrieved within 12 hours, meaning it was largely untainted by Earthly minerals and waters.

An initial analysis of the meteorite fragment last September revealed that it contained the first-ever extra-terrestrial water detected in a meteorite that had fallen to Earth.

Now, the new analysis suggests the Winchcombe meteorite may be a new class of weak meteorite that has never been studied before. According to Dr. Chan, "meteorite fall happens all year round, however, what makes this meteorite fall so unique is that this is the first meteorite to have been observed by numerous eyewitnesses, recorded, and recovered in the U.K. in the last 30 years."

"Winchcombe belongs to a rare type of carbonaceous meteorite which typically contains a rich inventory of organic compounds and water," Chan continued. "The first Winchcombe meteorite stone was recovered within 12 hours of the fireball observation event and properly curated to restrict any terrestrial contamination. This allowed us to study the organic signature truly essential to the meteorite itself."

The first meteorite of its kind recovered in the UK

The recovery of the Winchcombe meteorite was the first time a carbon-rich chondritic meteorite was ever recovered in the United Kingdom. Chan said it was "an honor to be leading the team on the organic analysis of the first-ever successful carbonaceous meteorite recovery in the United Kingdom."

"Studying the organic inventory of the Winchcombe meteorite provided us with a window into the past, how simple chemistry kick started the origin of life at the birth of our solar system," she continued. "Discovering these life's precursor organic molecules allowed us to comprehend the fall of similar material to the surface of the Earth, prior to the emergence of life on our own planet.

Scientists will continue to analyze the Winchcombe meteorite, as it could reveal a great deal about how life eventually flourished on Earth. A recent study, for example, of Japan's Hayabusa-2 mission asteroid sample, suggested that Earth's water may have come from asteroids.

Dr. Chan and colleagues' paper was published in the journal Meteoritics & Planetary Science.

Abstract:

The rapid recovery of the Winchcombe meteorite offers a valuable opportunity to study the soluble organic matter (SOM) profile in pristine carbonaceous astromaterials. Our interests in the biologically relevant molecules, amino acids—monomers of protein, and the most prevalent meteoritic organics—polycyclic aromatic hydrocarbons (PAHs) are addressed by analyzing the solvent extracts of a Winchcombe meteorite stone using gas chromatography mass spectrometry. The Winchcombe sample contains an amino acid abundance of ~1132 parts-per-billion that is about 10 times lower than other CM2 meteorites. The detection of terrestrially rare amino acids, including α-aminoisobutyric acid (AIB); isovaline; β-alanine; α-, β-, and γ-amino-n-butyric acids; and 5-aminopentanoic acid, and the racemic enantiomeric ratios (D/L = 1) observed for alanine and isovaline indicate that these amino acids are indigenous to the meteorite and not terrestrial contaminants. The presence of predominantly α-AIB and isovaline is consistent with their formation via the Strecker-cyanohydrin synthetic pathway. The L-enantiomeric excesses in isovaline previously observed for aqueously altered meteorites were viewed as an indicator of parent body aqueous processing; thus, the racemic ratio of isovaline observed for Winchcombe, alongside the overall high free:total amino acid ratio, and the low amino acid concentration suggest that the analyzed stone is derived from a lithology that has experienced brief episode(s) of aqueous alteration. Winchcombe also contains 2- to 6-ring alkylated and nonalkylated PAHs. The low total PAHs abundance (6177 ppb) and high nonalkylated:alkylated ratio are distinct from that observed for heavily aqueously altered CMs. The weak petrographic properties of Winchcombe, as well as the discrepancies observed for the Winchcombe SOM content—a low total amino acid abundance comparable to heavily altered CMs, and yet the high free:total amino acid and nonalkylated:alkylated PAH ratios are on par with the less altered CMs—suggest that Winchcombe could represent a class of weak, poorly lithified meteorite not been previously studied.