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Astro-Dictionary: Light Bridge |
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When you observe a large sunspot system, you may notice light streaks that appear to cross the umbra, which is the darkest part of the sunspot. This is a light bridge. It might look like a solar flare, but flares are short lived and appear more as long-lasting "flashes".
Light bridges the length of a planet can form on the Sun in a matter of hours as large sunspot groups decay. The above photo of the sun shows two such light bridges that appeared in May 2000. The 5000-kilometer long bridges connect moderately dark penumbral regions across the cooler sunspot umbra. Material tends to rise from below and fall rather than to cross the light bridges. As days progressed, the bridge region expanded to fill the void as the sunspots moved apart and decayed.
This image from the Swedish Solar Vacuum Telescope was made possible by adaptive optics that correct for the blurring of the Earth’s atmosphere.
