STEREO - Solar Terrestrial Relations Observatory
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Important notice about STEREO Behind

Coronal Hole with Nearby Activity

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STEREO (Behind) watched over a 48-hour period (April 23-25, 2010) as a substantial coronal hole (the much darker area) rotated towards solar center, while three small coronal mass ejections erupted from active regions near it (above and to the right). Coronal holes appear darker in extreme UV light because there is less material there that the spacecraft is imaging. They are a source of high-speed solar wind that streams particles out into space from there. When that coronal hole rotates around to where it faces Earth (in early May), gusts of solar wind will likely buffet Earth a few days later and generate some aurora at higher latitudes.


Last Revised: November 03, 2017 13:33:06 UTC
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