Comet 67P Reveals Building Blocks of Life in Stinky Space Cloud
Finn's Take· TL;DR- Rosetta spacecraft detected glycine and phosphorus at Comet 67P, marking first definitive proof comets carry life's chemical building blocks.
- Discovery supports theory that asteroids and comets delivered organic molecules to early Earth, potentially seeding conditions for life's emergence.
- Comet's 140+ detected molecules reveal these cosmic bodies as sophisticated chemical labs preserving prebiotic chemistry ingredients for billions of years.
A Cosmic Chemistry Lab with a Foul Smell
Between 2014 and 2016, the European Space Agency's Rosetta spacecraft flew alongside Comet 67P/Churyumov-Gerasimenko and analyzed the gas streaming off it. The list of compounds it found reads like a catalogue of unpleasant smells: hydrogen sulfide (rotten eggs), ammonia (a horse stable), formaldehyde, hydrogen cyanide (bitter almonds), and several others. Yet hidden within this cosmic stench were discoveries that could reshape our understanding of how life began on Earth.
Ingredients regarded as crucial for the origin of life on Earth have been discovered at the comet that ESA's Rosetta spacecraft has been probing for almost two years. They include the amino acid glycine, which is commonly found in proteins, and phosphorus, a key component of DNA and cell membranes. This marks the first time scientists have made unambiguous detections of these life-building molecules directly at a comet.
Breaking New Ground in Space Biology
This is the first unambiguous detection of glycine at a comet , according to Kathrin Altwegg, principal investigator of the ROSINA instrument that made the measurements. Previous hints of glycine were found in samples from Comet Wild-2 by NASA's Stardust mission in 2006, but possible terrestrial contamination of the samples made the analysis extremely difficult.
Rosetta measured 67P directly, in space, while flying through the comet's coma. The detections were repeated, strongest near the comet's closest approach to the Sun in August 2015, and correlated with dust, which suggests the glycine was released from icy grains as they warmed. This provided the definitive proof scientists needed to confirm comets as carriers of life's chemical ingredients.
Ancient Delivery System for Life's Building Blocks
Scientists have long debated the important possibility that water and organic molecules were brought by asteroids and comets to the young Earth after it cooled following its formation, providing some of the key building blocks for the emergence of life. The Rosetta discoveries add compelling evidence to this theory, though they don't prove comets actually created life on Earth.
It means a comet preserved and released some of the simple chemical pieces that life uses: an amino acid, a biologically important element, and precursor molecules that point to possible routes for making them. The finding supports a hypothesis, advocated for decades, that comet and asteroid impacts could have delivered such molecules to the early Earth.
Implications for Understanding Life's Origins
The multitude of organic molecules already identified by ROSINA, now joined by the exciting confirmation of fundamental ingredients like glycine and phosphorous, confirms our idea that comets have the potential to deliver key molecules for prebiotic chemistry , says Matt Taylor, Rosetta project scientist. The spacecraft detected more than 140 different molecules in the comet's atmosphere during its mission.
These findings transform our view of comets from simple "dirty snowballs" into sophisticated chemical laboratories that preserved the building blocks of life for billions of years. While the cosmic stink of Comet 67P might offend our noses, its chemical treasure trove could hold keys to understanding how life emerged not just on Earth, but potentially throughout the universe.