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Noctilucent clouds and an aurora

Auroras stem from activity on the sun and so are seen when the sun has been active. Noctilucent clouds are seasonal, seen in late May through August each year.

View larger. | Noctilucent clouds - the electric-looking clouds near the horizon in this photo - and a greenish aurora, higher in the sky, seen by Harlan Thomas in Canada on June 8, 2015.

View larger. | Noctilucent clouds – the electric-looking clouds near the horizon in this photo – and a greenish aurora, higher in the sky. Photo taken by Harlan Thomas in Alberta, Canada last Sunday night.

Harlan Thomas was out all night on the night of June 7-8, 2015, capturing photos of a two-for-one sky event. There was an aurora, or northern lights, and also noctilucent clouds – glowing silver-blue clouds that sometimes light up the night sky visible from high latitudes.

Auroras form after large flares on the sun that may release coronal mass ejections, or CMEs, into space. The CMEs are gusts of charged solar particles moving outward from the sun, hurtling across space. If Earth is in the path of the particle stream, our planet’s magnetic field and atmosphere react to produce auroras. Read more: What causes the aurora borealis or northern lights?

Noctilucent clouds, on the other hand, are strictly an atmospheric phenomenon. They form in the highest reaches of Earth’s atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth’s surface. They’re are thought to be made of ice crystals that form on fine dust particles from meteors. They are a seasonal phenomenon, and NASA said this year the season for them began a bit earlier than usual, in about mid-May. Read more: The secrets of night-shining clouds

Thanks for submitting to EarthSky, Harlan! Beautiful shot.

Bottom line: Photo of noctilucent clouds and an aurora, seen simultaneously on the night of June 7-8, 2015 from Canada.

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Deborah Byrd

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