Lightning in Our Solar System
Written by Colin Devroe · 13 May 2014
Recently, I was reading through the events of the 1700s on Wikipedia (as I’m sure you do nightly too) and came across a random bit about lightning causing some fires prior to buildings being equipped with lightning rods.
This, of course, led me to read everything I could find about lightning both on Wikipedia and the web at large. Then I got to thinking ‘I wonder if lightning happens on other planets or moons in our Solar System?’
On Earth lightning happens pretty frequently. Roughly 3,000 times a minute, actually. So, we humans are pretty used to it. Unfortunately, it is estimated that 73 people a year die due to lightning strike in the US alone.
So, does lightning happen on any other planets in the Solar System? On any moons? And, with any more or less frequency and severity than here on Earth?
Lightning has been confirmed through direct observation on Jupiter, Saturn, and Venus. Other planets are rumored to have lightning, such as Uranus and Neptune, however it hasn’t been confirmed by observation yet. Why the rumors? Well, a planet must have an atmosphere that can create an electrical charge, and the planets are emitting radio waves consistent with the signature of lightning. My guess is that we’ll end up observing lightning on more and more objects in our Solar System as we get better and better at observing them.
Images: Left, lightning on Jupiter. Right, lightning on Saturn. Both credit: NASA/JPL.
Lightning is caused by a positive charged bit of atmosphere traveling over or under a negative bit of atmosphere. An equalization of these charges must happen and when something “gets in the way” a strike occurs. Within this interaction there is a bit of magic that happens (scientists are still trying to figure it all out) and then POP!, lightning.
There is no need to guess whether or not there is lightning on Jupiter, though. Jupiter has some serious lightning. It has been closely observed since 1979’s Voyager missions. Since then, lightning on Jupiter has been observed several times. The lightning on Jupiter is, in a word, insane. Jupiter’s lightning can often be classified as superbolts. According to Wikipedia, superbolts “are bolts of lightning around a hundred times brighter than normal. On Earth, one in a million lightning strikes is a superbolt.”
Superbolts aren’t limited to Jupiter. In 2009 the Casini spacecraft managed to capture images of lightning on the night side of Saturn. Side note: The interesting thing about Saturn’s thunderstorm is that it happens in the exact same spot on Saturn every few months. Fascinating.
What else causes lightning? Volcanoes. IO, Jupiter’s moon and the second-largest moon in the Solar System, has 300 active volcanoes on it. So does this mean it has lightning? Sorry to spoil it, but, no. Lightning needs an atmosphere to occur naturally and IO doesn’t have one. It has been postulated, though, that IO’s volcanic activity can have some affect on Jupiter’ lightning.
Saturn’s moon Titan is the only moon in the Solar System with an atmosphere. So, does it have lightning? Shhhh! We’re listening for it. It turns out we’re trying pretty hard to listen for thunder on Titan to confirm that lightning is happening there. So far, we haven’t observed nor heard thunderstorms on Titan. But we’ll see, or hear.
I’m glad I went down this rabbit hole for a bit. It is fascinating stuff. The next time you see some lightning think about Jupiter and Saturn’s superbolts.