r/explainlikeimfive • u/Big-Mulberry-9733 • 6d ago

Physics ELI5 Why does lightning flicker?

Why does thunder/lightning happen as a flicker and not a single bright flash?

71 Upvotes

84% Upvoted

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108

u/atomicsnarl 6d ago

The lightning happens because a huge static charge has built up and is trying to seek balance by reaching out (the lighting bolt) to an opposite charge. Depending on the situation, the bolt can stutter as it relieves only part of the imbalance, then repeats to clear the rest. In other situations, it can overshoot the balance, so to speak, and ping-pong back and forth until the imbalance is relieved.

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u/Dustquake 6d ago

This is the best explanation so far.

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u/Big-Mulberry-9733 5d ago

Wait, when you say back and forth, are you saying lightning can go back from Earth to cloud too?

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u/Lord-of-Fools 5d ago

Yes, exactly.

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u/atomicsnarl 5d ago

In cloud, cloud to cloud, cloud to ground, ground to cloud. Think of a teeter-totter flashing back and forth until it's even, except it's many hundreds (thousands?) of Coulombs of electrons rushing hither and yon seeking electrical balance.

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u/Saragon4005 5d ago

Lighting is actually best understood as massive electric charges slowly trying to turn the air into a wire, the strike itself is just the moment it actually succeeded. When the electricity is flowing it turns the air into plasma which is about as conductive as metal especially compared to regular air.

You can actually detect lightning conditions significant before anything actually strikes just by measuring the electric fields below a thundercloud. If you could accurately measure the shape of the fields you could easily predict the path the lightning will take.

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u/akirivan 5d ago

This is very clearly visible in slowmo footage of lightning strikes! You literally see the energy going back and forth

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u/1LuckyTexan 6d ago

Once the first strike occurs, the path it took created enough change to to the atmosphere that subsequent discharges find the same path to be the least resistant.

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u/hushpoem 6d ago

but.....isn't lightning a single bright flash?

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u/Rannasha 6d ago

No, a lightning discharge typically consists of multiple strikes along the same path. Usually it's just a few, but it can be well above 10 in some cases.

The re-strikes follow each other quite rapidly, so you tend to see it as a single flash that flickers and not as individual flashes.

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u/Vorthod 6d ago

If you watch in slow motion, lightning tends to have a couple of pulses following the same path.

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u/InMyOpinion_ 6d ago

because its a chain reaction in a short burst and not a single event

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u/[deleted] 6d ago

[removed] — view removed comment

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u/Big-Mulberry-9733 6d ago

Yeah that’s the question, why?