Lightning on exoplanets: Benefits to learning physics outside the solar system

Whether lightning strikes a Danish treetop or a volcano on Venus, it is the same physical phenomenon created by a voltage difference in the atmosphere.  

When students need to learn about lightning, there is no reason to stay at terra firma. In fact, it is advantageous to look far beyond our solar system, according to Oriel Marshall, PhD student at the Department of Science Education and the University of Antwerp. 

"Exoplanets are wierd and we don't know much about them," said Oriel Marschall.  

"They give us a free pass to imagine. You can make up any planet and reasonably say it exists out there somewhere. In a way, exoplanets give access to a huge pile of mini-experiments." 

The forefront of astrophysics research

As part of the CHAMELEON research team looking at the chemical composition of exoplanet atmospheres, Oriel Marshall is working to bring this part of astrophysics' cutting-edge research into the classroom. And lightning is a good link to the secondary school curricula.  

"We see lightning in several places in our solar system. We know it happens on Saturn, Venus, Jupiter and Uranus. We think it also happens on planets outside the solar system - because why shouldn't it? We can't see it, but we can model it," said Oriel Marshall. 

Compared to the piles of data we have on our closest planetary neighbors; our models of exoplanets are very simple. 

"In this way, students can work with the exoplanet in a simpler way, but still relate to the fact that it is a physical place that exists. It's as close to a real place as our knowledge can bring us. When students take their physical understanding back to earth, they can better understand that the same physical laws apply." 

Lightning inquiry

To teach students about lightning on exoplanets, they must first learn how lightning works. To this end, Oriel Marshall has developed a lesson in which students work inquiringly with phenomena such as static electricity.

In this lesson, students are busy understanding lightning and the new physics concepts that come with it. To tie that knowledge to exoplanets, Oriel Marshall follows up with another lesson.

"From the first lesson, students should learn that special conditions are needed for lightning to strike - you need you need a semi-conductive atmosphere, charged particles, and so on. And in the second lesson, students can use the knowledge they have and see if there would be lightning strikes on planets we don't know," said Oriel Marshall.

The model of a real exoplanet 

For the second leasson Oriel Marshall has developed an interactive online dashboard based on data from exoplanet research together with PhD student Pieter Steyaert. 

"The digital platform allows students to explore an exoplanet through real astrophysics data. The idea is that the student can look at a climate model of the planet with wind speed, temperature. Here they can study the electric fields in different places on the planet and assess where lightning would most likely strike." 

Initially, students can examine two planets – a fictional Earth-like planet completely covered in water and a model of a real exoplanet locked to its star and therefore with a permanent night side and a permanent day side.  

"That also presents some interesting implications for the occurrence of lightning," said Oriel Marshall.  

"As opposed to just looking at lightning on Earth, this gives students the opportunity to use their knowledge of lightning in a new and different context, but one that is still real. And in this way, they learn to use their new knowledge in several different situations."