Electrical discharges occur in the atmosphere of Mars, although they are very different from lightning on Earth. An electrical activity that could hinder the search for past life on the planet and influence exploration missions.
A team of researchers with Spanish participation publishes in Nature a study based on atmospheric sounds collected by NASA’s Perseverance rover over two Martian years.
Electrical activity occurs not only on Earth, but also on planets such as Saturn and Jupiter, but until now it had not been directly demonstrated on Mars, although it had been theorized about.
This electrical activity has been detected in the form of triboelectric discharges, a kind of “microscopic sparks”, similar to the small discharges we feel when we touch our hair and a metal door, explains researcher Germán Martínez, from the Center for Astrobiology (CAB).
Martínez, one of the signatories of the research, tells EFE that they cannot be compared with the rays that occur on Earth, which are “about 200 million times more energetic than the sparks that we have detected on Mars,” and says that the largest would be like the one used to start a car.
Mars is a very dusty planet and is characterized by its wind storms and dust devils, which are the basis of these electrical discharges.
When the wind lifts the dust particles, they rub against each other, which creates an electric field powerful enough to reach the so-called breakdown threshold, which is what creates the triboelectric effect, indicates Martínez.
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Mars, with its tenuous atmosphere of carbon dioxide, is a cold, dry and dusty world, where the wind is sometimes very intense, blows in gusts, and organizes whirlwinds and ascending bubbles of dust, and can form fronts of hundreds of kilometers of gigantic storms, recalls the researcher at the University of the Basque Country (UPV/EHU) Agustín Sánchez Lavega.
“So we expect that the hitherto elusive electrical discharges will be very abundant when these environmental conditions occur,” adds Sánchez, also a signatory of the research, in a statement from his university.
The team identified 55 sparks of this type, almost all associated with wind eddies or atmospheric conditions where there were moving dust fronts.
The discovery of this phenomenon has various implications, among which Martínez highlights that electric fields create perchlorates, which degrade organic molecules, making the current search for evidence of past life on the planet difficult.
“If we are looking for biosignatures, we have to keep in mind that they may have disappeared or degraded. This phenomenon is important to understand the lack, perhaps, of those signs of life” on Mars.
Furthermore, the existence of these electrical discharges must be taken into account when carrying equipment or in future human missions, “because we do not want a sensor to stop working due to an electrical spark,” he says, although they are eventualities that are already taken into account and so far no mishap of this type has occurred.
Another aspect that may be affected is the weather prediction models on the planet, especially when there are human missions, since the presence of electric fields may mean that less wind than previously thought is necessary for dust to be injected into the atmosphere.
The team, led by the University of Toulouse (France), used recordings of sounds from the planet’s atmosphere made by a microphone on the Supercam instrument, one of those carried by Perserverance.
When triboeloelectric discharges occur – describes Martínez – an associated magnetic field is created, which produces an interference, a signal, which has a very defined pattern and which is collected in the acoustic signal recorded by the microphone.
With information from EFE
