The small spark that transfers a charge from one carbon dust particle to another, generating phenomena like lightning and possibly catalyzing life itself, is finally revealing its secrets.
Physicists have long puzzled over what factor governs the direction of charge flow when two particles of the same composition collide. A new study by researchers at the Institute of Science and Technology Austria (ISTA), published in Nature, finally answers this long-held question, providing new context for how this exchange may have produced the volcanic lightning that ignited life on Earth.
The Spark of Lightning
A mere spark traded between particles stands at the center of some of the universe’s most interesting phenomena, ranging from massive planet-forming disks around young stars to dust storms and volcanic lightning found right here on Earth.
The origin of life on Earth as a primordial soup that interacted with volcanic lighting to create the first amino acids, and later proteins, is a concept first developed in the 1950s. Intriguingly, in recent years, NASA’s Perseverance rover has detected organic molecules possibly made by life, as well as lightning-like electrical discharges in dust storms on Mars.
It has become increasingly likely that the Red Planet, which may have hosted life at some point in the past, if not presently, held the same lightning and chemical preconditions we expect life on Earth to have arisen from.
“There is strong speculation that large complex organic molecules were first formed due to sparks in rather common gases,” lead author Scott Waitukaitis told the Debrief. “On the primordial earth, such sparks were either due to atmospheric or volcanic lightning.”
“In the case of the volcano, the particles colliding are all primarily made of oxides,” Waitukaitis continued. “Hence, the charge exchange between oxides directly contributes to the volcanic lightning that may have “sparked” prebiotic chemistry.”
Exploring Charge Transfers
While not all such events are as dramatic as the origin of life, charge exchanges between particles are common in nature. Despite decades of research, scientists have struggled to determine what dictates the direction of charge flow between two insulating solids.
The ISTA team focused on a previously overlooked factor: environmental carbon-based molecules present on material surfaces.
To investigate, the researchers used silica—one of the most common solid materials in the universe—as their test medium. Early measurements revealed unexpected complexity. Even brief contact with the tweezers used to handle the silica resulted in measurable charge transfer.
To eliminate this interference, the team developed an acoustic levitation system that allowed them to suspend silica grains without physical contact. They then bounced individual grains off a silica plate to measure charge transfer before and after collisions.
Analyzing Charge Exchanges
After repeated measurements, the team noticed certain samples routinely charged negatively, with others regularly charged positively. This led the team to ponder why the charge was flowing in a specified direction, which varies piece to piece, when they are all the same material. Additionally, the team was interested in investigating if this tendency could be reversed in a specific piece of silica.
Immediately, the team’s findings contradicted the prevailing models, which held that random surface variations drove the charge polarity.
“Essentially, scientists imagined a ‘dairy cow pattern’ model,” said co-author Galien Grosjean. “Initially, I thought that we would validate this model and move forward. We expected random fluctuations averaging out to zero as the grains rotated and made contacts on different tiny patches,” said Scott Waitukaitis.
The team struggled for some time to identify a common factor correlated to the charge polarity, continuing to chase dead ends, such as humidity and the role of water molecules, as possible explanations. After running through a wide range of factors, the team finally found a correlation with heat. When heated, the samples consistently began to negatively charge upon contact.
“Since quartz glass is highly resistant to thermal changes, heat does not affect the material itself,” Grosjean said. “As a result, we thought that any alteration must be due to molecules adsorbed to the material’s surface.”
Further experiments using plasma to strip surface layers produced the same effect.
Expanding Charge Research
“At this point, we started contacting other groups that study material surfaces and can precisely measure surface compositions to compare the samples before and after baking,” Grosjean said. “That’s when we found that subjecting the materials to such treatment stripped them of their natural coating of environmental carbon species.”
This use of plasma to move carbon is a standard procedure in surface science. The team suspected that carbon was the key factor, but still lacked the necessary proof. Over the course of lengthy observations, the team noted that the charge-setting effect of baking or plasma scoping wore off within a day.
“In parallel, our collaborators showed that the carbon species also returned to the materials’ surface over the same period, making the correlation much stronger,” Grosjean said.
The environmental carbon takes much longer to return to the silica’s surface than water, a factor they had previously ruled out, indicating it as the driver of charge direction.
The team then examined other insulating oxides to determine if they experienced the same effect from environmental carbon. Materials such as alumina, spinel, and zirconia were cleared of carbon species without stripping, then subjected to collisions. The team found that the samples formed a triboelectric series, ordered by the polarity of their charges.
The researchers suspect that this demonstrates that charge is determined by a combination of intrinsic qualities and the influence of surface carbon. They found that by stripping the surface of certain materials, they could reverse the triboelectric series, showing that carbon can be even more important than the materials’ inherent properties.
The Effects of Tiny Charges on a Large Universe
Waitukaitis says that research like this is far from simple, which is part of what made the underlying phenomenon so elusive.
“These experiments are really hard,” Waitukaitis said. “The carbon coating is never at equilibrium; a single monolayer of carbon already makes a difference, and the materials are sensitive to the slightest touch.”
“That’s why the phenomenon remained unexplained for so long,” he added.
The team also examined silicon-based polymers, which behaved differently—highlighting that the phenomenon is not universal across all materials.
“It is tempting to think that any finding must apply to all materials,” added Grosjean. “But we stopped making this mistake.”
The researchers suggest that static electricity between insulating oxides may play a fundamental role in processes ranging from planetary formation to prebiotic chemistry.
“In our lab, the focus is on why materials exchange charge. Now that we know what matters (the carbonaceous molecules on the surface), we want to understand why,” Waitukaitis concluded. “If we can accomplish this, it will help those that study planet formation make definitive statements about what is happening in protoplanetary disks and, therefore, to what extent static electricity plays a role.”
The paper, “Adventitious Carbon Breaks Symmetry in Oxide Contact Electrification,” appeared in The Astronomical Journal on March 18, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.