This stripy band of clouds off the southern coast of Australia is an example of a phenomenon in the atmosphere called “gravity waves”.
Not to be confused with gravitational waves, gravity waves are ripples that occur between layers of fluids with different densities.
Much as the wake of a boat is formed when water is pushed upward by the boat and pulled down again by gravity, these clouds are formed by the rise and fall of air columns.
As the wave moves through the cloud band, the wave peaks appear clouds and the troughs appear cloud-free.
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