Cosmic dust swirling around the Helix
nebula, ejected from an ageing star similar to the sun. Credit: NASA
A
Sydney Ph.D. student has recreated a tiny piece of the universe inside a bottle
in her laboratory, producing cosmic dust from scratch. The results shed new
light on how the chemical building blocks of life may have formed long before
Earth existed. Linda Losurdo, a Ph.D. candidate in materials and plasma physics
in the School of Physics, used a simple mix of gases—nitrogen, carbon dioxide
and acetylene—to mimic the harsh and dynamic environments around stars and
supernova remnants.
By subjecting these gases to intense
electrical energy, she generated carbon-rich "cosmic dust" similar to the material
found drifting between stars and embedded in comets, asteroids and meteorites.
Her results are published in The Astrophysical Journal.
The dust she created contains a complex
cocktail of carbon, hydrogen, oxygen and nitrogen—known collectively as CHON
molecules—which are central to
many organic substances essential for life.
"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.
"This can give us huge insight into
how 'carbonaceous cosmic dust' can form in the plasma puffed out by giant, old
stars or in cosmic nurseries where stars are being born and distribute these
fascinating molecules that could be vital for life. It's like we have recreated
a little bit of the universe in a bottle in our lab."
Cosmic dust is known to form in extreme
astrophysical environments, where molecules are constantly bombarded by ions
and electrons. Scientists can identify this dust in space because it emits a
distinctive infrared
signal—a molecular
fingerprint that reveals its chemical structure.
The dust produced in Losurdo's experiments showed the same tell-tale infrared signatures, confirming the laboratory process closely mirrors what happens in space.
Schematic diagrams contrasting the
structural changes induced in amorphous CHON networks arising from the
nonequilibrium, transient thermal spike effect of ion bombardment and the
equilibrium thermal effect of postsynthesis annealing. Credit: The Astrophysical Journal (2026). DOI: 10.3847/1538-4357/ae2bfe
Building blocks of life
One of the enduring questions in
science is how life began on Earth. Researchers are still debating whether the
earliest organic molecules formed locally on our young planet, arrived later
aboard comets and meteorites, or were delivered during the earliest stages of
solar system formation—or some combination of all three.
Between about 3.5 and 4.56 billion
years ago, Earth was bombarded by meteorites, micrometeorites and
interplanetary dust particles originating from asteroids and comets. These
objects are thought to have delivered vast amounts of organic material to the planet's
surface. Yet the origins of that material remain mysterious.
"Covalently bonded carbon and
hydrogen in comet and asteroid material are believed to have formed in the
outer envelopes of stars, in high-energy events like supernovae, and in
interstellar environments," Losurdo said.
"What we're trying to understand are the specific chemical pathways and conditions that incorporate all of the CHON elements into the complex organic structures we see in cosmic dust and meteorites."
Scanning electron microscope images of
laboratory synthesized dust show evidence for aggregation, surface smoothing by
ion bombardment, and compaction caused by annealing. Credit: The Astrophysical Journal (2026). DOI: 10.3847/1538-4357/ae2bfe
How they did it
In the experiment, the team,
consisting of Losurdo and her supervisor, Professor David McKenzie, used a
vacuum pump to evacuate air from glass tubes, recreating the near-empty
conditions of space. Nitrogen, carbon dioxide and acetylene were then introduced.
The gas mixture was exposed to about 10,000 volts of electrical potential for
about an hour, creating a type of plasma known as a glow discharge.
Under
this intense energy, molecules broke apart and recombined into new, more
complex structures. These compounds eventually settled as a thin layer of dust
on silicon chips placed inside the tubes. The collected dust at times looks
like glittering collections of cosmic material.
Professor McKenzie, co-author on the
paper, said the work will allow scientists to probe conditions that are
otherwise impossible to study directly.
"By making cosmic dust in the lab,
we can explore the intensity of ion impacts and temperatures involved when dust
forms in space," Professor McKenzie said. "That's important if you
want to understand the environments inside cosmic dust clouds, where
life-relevant chemistry is thought to be happening.
"This also helps us interpret what
a meteorite or asteroid fragment has been through over its lifetime. Its
chemical signature holds a record of its journey, and experiments like this
help us learn how to read that record."
Beyond insights into the origins of
life, the researchers aim to build a comprehensive database of infrared
fingerprints from lab-made cosmic dust. Astronomers could then use this library
to identify promising regions of space—in stellar nurseries or the remnants of
dead stars—and work backwards to understand the processes shaping them.
By recreating cosmic chemistry on Earth, the research opens a new window onto deep stellar processes—and the ancient steps that may have helped make life on Earth possible.
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