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A balloon mission from NASA observed rare electric blue clouds.

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These are polar mesospheric clouds, or PMCs.

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They are only visible during twilight

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and form above Earth’s polar regions at the upper reaches of the atmosphere.

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As Earth’s uppermost clouds at around 50 miles high,

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PMCs are composed of ice crystals that glow a bright blue or white when reflecting sunlight.

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They are extremely sensitive to environmental factors like water vapor and temperature.

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Atmospheric motions like airflow over mountains or thunderstorms

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can disturb the atmosphere and cause waves that can propagate to very high altitudes.

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These waves are known as gravity waves

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and although they are invisible, they can be seen as they move through PMCs.

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Gravity waves lead to turbulence

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- chaotic movement in the atmosphere

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that can influence weather and climate, and their predictions.

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But the exact causes and effects of turbulence are not well understood.

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To better understand this complex process,

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scientists sent a giant balloon to observe gravity waves in PMCs.

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See you in Canada.

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The crewless balloon traveled to 50 miles high

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and floated from Sweden to Canada over 5 days, in July 2018.

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A laser radar on the balloon measured the PMC altitudes

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and the atmospheric temperature that affects their formation and brightness.

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And from six million camera images captured from the balloon,

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scientists could see both large and small ripples caused by gravity waves.

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A better understanding of turbulence can help improve weather forecast models

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and our understanding of processes around Earth,

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which affect our satellites and assets in space.

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