From its new home on the Red Planet, NASA’s Perseverance robber possibly soon in the front row of an alien light show.
When the next seasonal dust storm passes through Jezero Crater (where the rover landed on Feb. 18), the air around the rover could crackle and glow with purple light from the collision of statically charged dust particles, a new study suggests.
These colorful sparks would almost certainly be too small and faint to threaten Perseverance, or any hypothetical people getting off Mars in the future, said lead study author Joshua Méndez Harper, a geologist from the University of Oregon. However, the presence of electrostatic forces on Mars could have far-reaching implications for how scientists understand the Red Planet’s atmosphere and its potential to promote life, Méndez Harper said.
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“Small sparks can catalyze the production of chemicals [impact] the presence of organic materials, “Méndez Harper told Live Science in an email.” A recent paper suggested that perchlorates – compounds that are toxic to many forms of life – can be generated from small-scale spills. “
The buzz about Mars
The new study will be published in the March issue of the journal Icarus, aims to provide a decisive answer to a question that has been buzzing with the scientific community for half a century: Can colliding particles generated by fast winds in the atmosphere of Mars generate electricity?
This process is known as triboelectric charging, that is, electricity produced by the friction of colliding particles or surfaces. On Soil, 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 one apocalyptic thunderstorm blasting through the ash column of an erupting volcano – the triboelectric result of ash particles colliding in mid-air.
However, on Mars it is unclear whether triboelectric charging is taking place at all. Since Mars has a much lower atmospheric pressure than Earth, powerful charges are unlikely to accumulate there, Méndez Harper said. Studies dating back to the 1970s have attempted to simulate Earth’s Mars dust storms by shaking up volcanic ash in small, low-pressure containers. Sometimes those particles (which have a similar composition to Mars dust) spark – but according to the new Icarus paper, these studies could be fundamentally flawed.
“These works did not take into account the possibility of recharging due to the interaction between simulated Mars dust and experimental containers enveloping it,” said Méndez Harper. “The containers often had completely different chemistries – plastic, metal or glass – that could have caused the observed electrical effects.”
In other words, in previous studies, any sparks observed could actually be between a dust particle and the side of the container that encloses it, rather than between two simulated Mars dust particles. These containers are made of things that don’t exist on Mars, which means the experiments don’t really teach us anything about what’s happening in the Red Planet’s dust storms.
Méndez Harper and his colleagues tried to correct this experimental design flaw in their new study.
As in previous experiments, the team used volcanic ash grains (from Mexico’s Xitle volcano, which erupted about 1,700 years ago) to simulate Mars dust particles and enclosed them in a glass tube under conditions simulating Mars’ atmosphere. However, unlike previous experiments, the team used jets from carbon dioxide to stir the granules in a “fountain” of colliding particles that never hit the container wall.
The team found that the colliding particles resulted in tiny triboelectric sparks, even when those dust particles didn’t come into contact with the container. For the researchers, this study thus provides the first reliable experimental evidence of triboelectric charging on Mars.
Red planet, purple glow
What would those accusations look like? It’s hard to tell. Although the researchers detected electronic shocks in their Mars dust fountain, they saw no visual effects from the collisions. Given the low atmospheric pressure on Mars, it is unlikely that even the most violent dust storms would ripple with lightning like Earth volcanoes or thunderclouds.
“A more likely possibility is that dust storms on Mars are showing countless tiny sparks – so-called streamer discharges and glow discharges,” said Méndez Harper. These small-scale electrical effects can cause dust clouds from Mars to glow purple; on Earth, sailors sometimes see a similar glow – known as St. Elmo’s fire – when the masts of ships scrape through a strong electric field.
The Perseverance rover could potentially get the first visual evidence of the phenomenon on Mars the next time a dust storm sweeps through the Jezero crater – or possibly even sooner, Méndez Harper said.
“Percy” is equipped with a small helicopter called Ingenuity; When the helicopter takes off or lands, the buzzing blades can generate enough dust to produce “visible discharges” near the rover, Méndez Harper said.
Don’t be shocked if you see it.
Originally published on Live Science.