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        Eclipse Over America | The Coronal Heating Problem

        Learn about the discovery of the high temperature of the Sun’s corona and how nanoflares may be the explanation, in this video from NOVA: Eclipse Over America. During a total solar eclipse in 1869, spectroscopic observations of the corona revealed a mysterious spectral line that did not match the spectra of any known element. Decades later, it was discovered that the spectral line was produced by iron at a very high temperature. Scientists do not fully understand how the corona can reach such high temperatures, but frequent explosive events—called nanoflares—could be the cause. Animations show how nanoflares may be produced by the twisting, breaking, and reconnection of magnetic field lines.

        To view the Teaching Tips for this video, go to Support Materials below. This resource was developed through WGBH’s Bringing the Universe to America’s Classrooms project, in collaboration with NASA.

        Visit the program page.


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