NASA’s helicopters flying over the Martian surface in the future might create a blue-purple glow around the wings, creating a beautiful light show on a planet that looks more or less like an arid post-apocalyptic wasteland. That glow is not something exclusive to Mars. In fact, it can be seen on the Earth in various forms already, and the process that leads to it all is called triboelectric charging.
In simple , when two objects are rubbed together, the friction between them leads to the transfer of electrons and creates an electric field as a result. Rubbing a balloon against your hair, only to see it stick to the wall is an example of triboelectric charging. When volcanoes erupt, the ash particles rubbing against each other lead to a charge buildup that generates lightning. The aurora seen on Mars is also a result of charged particles from the Sun bombarding the gas and making the surroundings glow as a result.
Something similar, but on a much smaller scale, is predicted to happen when future Mars helicopters fly above the Red Planet’s surface. In a study published in seen with helicopters flying on Earth. Well, it has to do with the unique atmospheric conditions on Mars.
Mars' Atmosphere Is Tailored For A Light Show
When a Martian vehicle’s rotor blades spin, the blades blow up dust particles from the surface that collide with the blades. In doing so, a charge builds up on the blades that create an electric field around it and the atmosphere starts to conduct electricity. The process is called an electron avalanche. The free electrons then crash against the gas molecules in the air to release more electrons and intensify the electric field. On Mars, that is more likely to happen compared to Earth. And that’s because the thickness of Mars’ atmosphere is just about one percent compared to that of Earth. Lesser atmospheric density means there are lesser gas particles to crash against.
With a lower number of particles to collide with, the electrons accelerate and easily knock out more electrons from surrounding gas particles. To do so, the electric field strength must be around 3 million volts per meter on Earth, but on Mars, only 30,000 Volts per meter is sufficient for the electrons to do their job. This electron avalanche will charge the space around a Martian helicopter’s rotors, causing it to glow. But it is worth noting here a glowing aura around the wings of a Martian helicopter is not a certainty. The prediction has been made based on laboratory measurements and computer modeling to see how an electron charge might build up around the rotating wings of a drone.
Sources: NASA, The Planetary Science Journal