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Night-Shining Clouds May Have Metal Lining

Irene Klotz, Discovery News

"It's possible that there could be a mono-coating," Rusch told Discovery News. "I think we're a little bit skeptical at this point, but we're certainly going to look at it. There's good thinking in that research."

Past studies of sodium and iron in the atmosphere show the metal vapors are more than 80 percent depleted when noctilucent clouds are present.

"The ice is like flypaper for the sodium," Bellan said, citing other experiments showing that when sodium sticks to ice it forms a metallic film.

"That's neat. You don't usually think of metal appearing in clouds," Bellan added.

The idea that noctilucent clouds are eating out atmospheric sodium is, admittedly, a long-shot, Bellan says, but the physics adds up.

"Ripples in the cloud of metal-coated ice grains reflect in unison and reinforce each other ... like an army marching in step across a bridge causes the bridge to vibrate," he said.

"The metal is responsible for the reflectivity," Bellan said. "I did the math."

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