Japanese tsunami caused "ripples" in the atmosphere


This photo is the first picture taken of "airglow ripples," the impacts of an ocean tsunami reflected in the sky.

No, really. Scientists have long known that powerful tsunamis can affect atmospheric particles. This is just the first time the phenomenon has been photographically documented. In this image, you can see the ripples in the sky over Hawaii. The red line marks the tsunami wave moving across the ocean surface. What's going on here? Alexandra Witze of Science News explains:

When the magnitude-9.0 quake ruptured the seafloor off eastern Japan on March 11, it displaced water that started rushing outward as a tsunami. Over the open ocean those waves were just centimeters high, but that small shift was enough to displace the air above the water's surface. The result: dense waves of atmospheric particles propagating upward.

Roughly 250 kilometers up in the layer known as the ionosphere, those waves encountered charged and neutral particles, slamming them together to combine and release a bit of energy.

On an ordinary night, skywatchers can see airglow from the odd particle collision in the ionosphere. But the passing tsunami caused more particle collisions than usual, which appeared as undulating waves moving in lockstep with the oceanic tsunami below.

Makela and his colleagues caught the event because their wide-angle camera, which sits atop the Haleakala volcano in Maui, photographs the sky every night looking for ionospheric disturbances.

Via Frank Swain