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From its new home on the Red Planet, NASA Perseverance rover could soon have a front row view of an otherworldly light show.
When the next seasonal dust storm passes through Jezero Crater (where the rover landed on February 18), the air around the rover could crackle and glow with a purple light from the collision of statically charged dust particles, suggests a new study. .
These colorful sparks would almost certainly be too small and faint to pose a threat to Perseverance, or to any hypothetical human who landed on March in the future, said lead study author Joshua Méndez Harper, a geologist at the University of Oregon. However, the presence of electrostatic forces on Mars could have broad implications for how scientists understand the Red Planet’s atmosphere and its potential to promote life, Méndez Harper said.
Related: Here’s the last thing NASA’s Opportunity rover saw before the lights went out
“Small sparks can catalyze the production of chemicals [impact] the presence of organic material, “Méndez Harper told Live Science in an email.” A recent article suggested that perchlorates – compounds toxic to many life forms – could be generated by small-scale releases. “
The buzz on Mars
The new study, which is expected to be published in the March issue of the journal Icarus, aims to provide a decisive answer to a question that has been buzzing in the scientific community for half a century: Can the collision of particles caused by high-speed winds in the atmosphere of Mars generate electricity?
This process is known as triboelectric charging, which is electricity produced by the friction of colliding particles or surfaces. Sure Earth, you can generate a small triboelectric spark, or static electricity, in your bedroom by rubbing your socks on the carpet and then touching a metal doorknob (youch!). Or, for a larger demonstration, you can marvel at a apocalyptic storm bolting through the ash column of an erupting volcano – the triboelectric result of the collision of ash particles in the air.
On Mars, however, it is not known whether triboelectric charging occurs. Because Mars has a much lower atmospheric pressure than Earth, powerful charges are unlikely to be able to accumulate there, Méndez Harper said. Studies dating back to the 1970s tried to simulate Martian dust storms on Earth by shaking volcanic ash in small containers at low pressure. Sometimes these particles (which have compositions similar to Martian dust) do spark – but according to Icarus’ new article, these studies may be fundamentally flawed.
“This work did not take into account the possibility of loading resulting from the interaction between simulated Martian dust and the experimental containers that contain it,” Méndez Harper said. “The containers often had very different chemistries – plastic, metal or glass – that could have produced the electrical effects observed.”
In other words, in previous studies, the sparks observed may have actually been between a dust particle and the side of the container that holds it, rather than between two simulated Martian dust particles. These containers are made of things that don’t exist on Mars, which means that the experiences really don’t tell us anything about what happens in the dust storms of the Red Planet.
Méndez Harper and his colleagues tried to correct this experimental design flaw in their new study.
Similar to previous experiments, the team used grains of volcanic ash (from the Xitle volcano in Mexico, which erupted around 1,700 years ago) to simulate Martian dust particles and locked them in a glass tube in conditions simulating the Martian atmosphere. Unlike previous experiments, however, the team used jets of carbon dioxide to mix the grains into a “fountain” of colliding particles that never touched the wall of the container.
The team found that the colliding particles resulted in small triboelectric sparks, even when those dust grains did not come into contact with the container. For the researchers, this study therefore provides the first reliable experimental proof of the triboelectric charge on Mars.
Red planet, purple glow
What would these charges look like? It’s hard to say. Although the researchers electronically detected shocks in their Martian dust fountain, they observed no visual effects resulting from the collisions. Given the low atmospheric pressure on Mars, even the fiercest dust storms are unlikely to reverberate with lightning like terrestrial volcanoes or storm clouds do.
“A more likely possibility is that Martian dust storms present countless small sparks – called streamer discharges and glow discharges,” Méndez Harper said. These small-scale electrical effects could cause Martian dust clouds to glow purple; On Earth, sailors sometimes see a similar glow – known as St. Elmo’s fire – when the masts of ships scratch through a strong electric field.
The Perseverance rover may be able to get the first visual evidence of the phenomenon on Mars the next time a dust storm sweeps through Jezero Crater – or maybe even sooner, Méndez Harper said.
“Percy” is equipped with a small helicopter named Ingenuity; when the helicopter takes off or lands, its whirring blades can stir enough dust to “produce visible shocks” near the rover, Méndez Harper said.
Don’t be shocked if you see it.
Originally posted on Live Science.
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