(CNN) A rarely-seen natural phenomenon has been captured on camera as it pulses through clouds over the ocean.
Atmospheric gravity waves can be seen in satellite images taken by Australian weather forecast service Weatherzone on Monday and Tuesday.
The images show the waves spreading out from the coast of Western Australia, sending ripples through clouds over the Indian Ocean.
The gravity waves were triggered by thunderstorms, with cold air flowing out from the squalls resulting in a disturbance in the atmosphere.
"The atmosphere is a big body of gas that acts like a fluid," said Ben Domensino, a meteorologist at Weatherzone. "It is exactly the mechanism as when a rock is thrown into the water, then the wave travels out from that source."
The invisible waves are quite common in the atmosphere, he added. They are typically invisible unless they cause motion in clouds that can be detected by satellites.
"Thunderstorms, air flowing over mountains and contrasting wind directions -- when you've got wind from two directions interacting with each other -- can also cause gravity waves," Domensino said.
The surges do not pose any danger, but pilots should be cautious about "rising and sinking air", he added.
The satellite also captured images of a sandstorm blowing over the dry Pilbara region in Western Australia.