Story Fuel: Biological Building Blocks Confirmed on Comet
Philae may have gone silent again, but the little lander lost managed to transmit some intriguing data in its most recent dispatch from Comet 67P: namely, the presence of chemical elements necessary for carbon-based life. Discovery of these molecules suggest a comet impact may have delivered for the ingredients of primordial Earth life eons ago.
“This is no cave!” And Philae’s discovery of biological chemicals on an asteroid is no giant predatory space worm, but exciting nonetheless.
In its latest issue, the journal Science reported analysis from two of Philae’s pre-programmed experiments, COSAC (Cometary Sampling and Composition) and Ptolemy, that carried out some research before the lander went offline. COSAC collected surface dust the lander stirred up during its first touchdown and identified 16 organic compounds, including several rich in nitrogen and carbon. Four of these—propionaldehyde, acetone, methyl isocyanate, and acetamide—have never been detected in comets before. Acetamide particularly excited scientists because it produces key molecules, such as like amino acids and DNA bases.
Meanwhile, Ptolemy’s sample of the comet’s coma (the haze of gases, ice, and dust surrounding its core) found mostly water vapor and carbon dioxide, but also precursors of formaldehyde. Most of us probably associate formaldehyde with specimens floating in jars, but it’s also important in biological chemistry, producing simple sugars like ribose. Now that Philae’s data has confirmed the existence of organic molecules in cometary ice, future experiments may simulate how they combine to form peptides and other chemical building blocks.
Mission personnel hope moving the Rosetta orbiter closer to Philae may allow them to re-establish communication with the lander, but right now 67P is approaching perihelion (the part of its orbit closest point to the sun) and flying too close might condemn Rosetta to the fate of Icarus. Later this year, when things cool off, the team may be able to link with Philae again and gather more data on the comet’s surprising composition.
Visit the Royal Chemistry Society for an more detailed chemical analysis of Philae’s new data, or read a comprehensive overview from Popular Mechanics.
