Lab-made cosmic dust points to chemistry that may have preceded Earth

University of Sydney researchers have produced cosmic dust analogues in glass tubes, creating carbon-rich material under conditions meant to resemble parts of space. The study matters because the dust carries chemical elements associated with organic molecules, offering a way to test how some ingredients linked to life may have formed before Earth existed.

The work was led by Linda Losurdo, a PhD candidate in materials and plasma physics in the university’s School of Physics, with Professor David McKenzie. Their findings were published in The Astrophysical Journal, according to the University of Sydney.

Dust made under space-like conditions

According to the university, Losurdo filled evacuated glass tubes with nitrogen, carbon dioxide and acetylene. The team then applied an electrical potential of about 10,000 volts for roughly an hour, producing a glow discharge plasma.

The high-energy process broke apart the gas molecules, allowing their components to recombine into more elaborate structures. The resulting material settled onto silicon chips inside the tubes as a fine coating of dust, the university said.

The laboratory dust contained combinations of carbon, hydrogen, oxygen and nitrogen. Researchers often refer to these elements together as CHON, and the university said they appear in many organic substances considered relevant to life.

Infrared signals match space material

Astronomers study cosmic dust by measuring the infrared light it emits, because those signals can reveal chemical structure. The University of Sydney said Losurdo’s samples produced infrared signatures like those seen from real cosmic material.

That match suggests the laboratory setup can reproduce parts of the chemistry thought to occur around stars, in interstellar regions and in material later preserved in comets, asteroids and meteorites. Losurdo said the approach could let scientists study the histories of such objects in the lab rather than waiting for samples to arrive on Earth.

The study examined carbonaceous cosmic dust analogues and how their signatures vary with ion impacts and temperature. McKenzie said making the material in the laboratory helps researchers test conditions that are difficult to measure directly in space, including the effects of energetic particles on forming dust.

What it may say about early chemistry

The University of Sydney said scientists are still investigating whether the first organic molecules tied to life formed on early Earth, arrived through impacts, were present as the solar system formed or came from several routes. From about 4.56 billion to 3.5 billion years ago, the planet was struck repeatedly by meteorites, micrometeorites and interplanetary dust particles from asteroids and comets, according to the university.

Researchers believe those objects delivered large amounts of organic material to Earth, but the origin of that material remains uncertain. Losurdo said carbon-hydrogen bonds found in comet and asteroid material are thought to have formed in stellar outer envelopes, supernova-related events and interstellar environments.

The team’s next goal includes building a database of infrared fingerprints from different lab-made cosmic dust samples. According to the university, astronomers could compare that reference set with observations of star-forming areas and the remnants of dead stars to identify where specific forms of dust are being made.

The same database could help scientists interpret meteorite and asteroid fragments, whose chemistry can preserve signs of temperature, radiation and particle impacts over time. The authors reported no competing interests, and the University of Sydney said the work was supported by its Microscopy Australia node and funded by the Australian Research Council.

This story draws on original reporting from ScienceDaily.