What would it take to cease the waiting of space rocks and be able to make the chemistry where we need it? Ph.D. student Linda Losurdo at a laboratory in Sydney has done something that is historically the prerogative of old stars and violent cosmic places: she has synthesized carbon-rich “cosmic dust.” A mixture of nitrogen, carbon dioxide and acetylene was pushed into a glow-discharge plasma inside evacuated glass tubes that simulated the conditions inside of space by driving it with approximately 10,000 volts over a period of roughly an hour. The debris and reassemblies that ensued deposited a thin dust film left on silicon chips, and chemical traces of which astronomers would otherwise call infrared “fingerprints” were used to identify genuine dust drifting through the interstellar.
It is not the glittering residue but its composition that is the major attraction. Losurdo analog dust has a complex composition of carbon, hydrogen, oxygen and nitrogen; sometimes referred to as the CHON elements- the chemical backbone of much of the biologically related organics. “We no longer have to wait for an asteroid or comet to come to Earth to understand their histories,” Losurdo said. “You can build analog environments in the laboratory and reverse engineer their structure using infrared fingerprints.”
The fact that the lab-to-sky connection is important, is due to the fact that dust is not merely rubbish; it is a molecular workshop, a transport system. Infrared astronomy uses dust as a barcode: molecules vibrate, absorb, and re-emit light in structured patterns that contain structure. The findings of Losurdo bring the gap between telescopic measurements and chemist interrogable conditions closer, and would allow the researcher to have controlled access to the inaccessible conditions. “By making cosmic dust in the lab, we can explore the intensity of ion impacts and temperatures involved when dust forms in space,” as Professor David McKenzie, the supervisor of Losurdo, stated.
Space observations are emphasizing the importance of having various paths taken into consideration. JWST data in the dwarf galaxy, Sextans A, which contains just 3 to 7 percent of the metal content of the Sun, exhibited production of dust which cannot be explained by the “standard ingredients,” such as grains containing largely of iron and the presence of polycyclic aromatic hydrocarbons (PAHs) in small sheltered pockets. The implication is practical: dust chemistry is adapted to the constraints, and infrared spectrum can conceal as much as it discloses unless there are laboratory analogs to make comparisons.
The extra type of grounding provided by returned samples is direct extraterrestrial organic inventories. Analysis of samples of asteroid Bennu by laboratories discovered the 5 canonical bases of RNA and DNA and 15 amino acids of proteinaceous building blocks, and a probable discovery of tryptophan in a PNAS experiment. Those discoveries indicate the existence of chemically diverse environments on small bodies, such as wet, alkaline ones, in which various reactions histories can be present in various rocks. Combined with man-made dust, the image changes to a network, dust develops in energetic stellar environments, evolves through irradiation and processing, and may subsequently be reworking by water-driven chemistry within asteroids prior to anything arriving on a planet.
Losurdo and others are also working on creating a reference library of infrared prints of fingerprints produced by laboratory dust. When such a database swells in size, the telescope spectra of stellar nurseries, or the remains of dead stars, can be more readily “read” as engineering-records, the history of matter in vibrations, than as a series of one-off mysteries until the next meteorite falls.
