# Are there lightning bolts on Mars?

Although the Martian atmosphere is thin, there are many atmospheric phenomena that occur on Mars: storms, dust devils, (carbon dioxide) snow,... Some storms even stir up the atmosphere of the entire planet!

During Martian storms, is there any lightning and thunder, like what we see during Earth storms? What about in the past, when atmospheric conditions were different, has there ever been any lightning on Mars?

While not seen yet, dustdevils on mars could also contain lightning as they generate electric fields close to the breakdown of air on mars.

"On Earth, with instruments we've measured electric fields on the order of 20 thousand volts per meter (20 kV/m)," Farrell says. That's peanuts compared to the electric fields in terrestrial thunderstorms, where lightning doesn't flash until electric fields get 100 times greater--enough to ionize (break apart) air molecules.

But a mere 20 kV/m "is very close to the breakdown of the thin Martian atmosphere," Farrell points out.

Paschen's law reflects the fact that as pressure decreases the mean free path increases, which allows an electron to gain more energy between one collision and the next, making it easier to produce an ionization cascade.

• +1 This is a good point! I'd never though of it before, but yes these low pressure atmospheres can have much lower breakdown voltages than either vacuum or what we have on Earth! I've added a bit of background, please feel free to roll back or edit further. – uhoh Oct 2 '20 at 0:21
• I saw FPGA and "My designs are flying a few hundred km above the earth" in your user profile; there may be some unanswered or insufficiently answered FPGAs in space! questions here. – uhoh Oct 2 '20 at 0:28
• +1! This is a much better explanation of what I was trying to say with my troublesome "last sentence". – IronEagle Oct 2 '20 at 19:31

Lightning may have been detected on Mars, although it currently appears to be rare, and attempts to replicate the 2006 results have failed so far.

New research found that the low pressure on Mars might be the reason why lightning is uncommon. The atmospheric pressure on Mars appears to be at a minimum for making lightning, as opposed to just coronal discharge. With less atmospheric pressure than it has now, more static charge would build up on each grain, making a sudden lightning bolt more likely. More pressure, and there would be more grains flying around, building up charge more quickly and increasing the chance of lightning. Thus the chance for a lightning bolt to happen, rather than just coronal discharge, is much lower than it is on Earth, and is in fact at a minimum. This could explain why there has been only one detection so far. Source

• Same link even! – Wayfaring Stranger Sep 30 '20 at 16:26
• Could you clarify your last non-link sentence? In its current form, I can paraphrase it to "less pressure would result in more, more and more pressure", which doesn't make sense. – Ruslan Sep 30 '20 at 22:01
• @Ruslan - fair point. I hope this helps a bit. The basis is that at the current pressure, the atmosphere would rather dissipate any energy that builds up, rather than letting it accumulate to lightning strikes. – IronEagle Sep 30 '20 at 22:09
• So back when the atmosphere was thicker, there might have been more lightning? – usernumber Oct 1 '20 at 7:38
• @usernumber - yes! – IronEagle Oct 1 '20 at 14:30

Lightning Detected on Mars, 2006 With those dust storms, it's difficult to believe that you would not get sufficient charge separation. At only a few hectopascal pressure, thunder might be hard to hear.

• I wondered if there would be another answer to this post by the time I finished... – IronEagle Sep 30 '20 at 15:29
• @IronEagle the following is as yet unanswered in Space SE: [Are there methods of lightning detection on Mars? – uhoh Sep 30 '20 at 16:15
• @uhoh - thanks for pointing me in that direction! Turns out this 2006 result is basically the only time anyone has detected lightning on Mars, even though there have been several different attempts, some spanning years in orbit. – IronEagle Sep 30 '20 at 18:48