Solar spectrum shifted from absorption to emission during eclipse
[CLICK ON IMAGE FOR HIGH RESOLUTION / Constantine Emmanouilidi]
In a flash, the visible spectrum of the Sun changed from absorption to emission on November 3rd, during the brief total phase of a solar eclipse.
[Normally a spectrum of the sun will show dark lines where where wavelengths of energy for elements have been absorbed by the gas cloud atoms and re-emitted in another direction. A spectrum of that redirected energy would appear as bright lines in an emission spectrum.]
[The above] fleeting moment is captured by telephoto lens and diffraction grating in this well-timed image from clearing skies over Gabon in equatorial Africa. With overwhelming light from the Sun’s disk blocked by the Moon, the normally dominant absorption spectrum of the solar photosphere is hidden.
What remains, spread by the diffraction grating into the spectrum of colors to the right of the eclipsed Sun, are individual eclipse images at each wavelength of light emitted by atoms along the thin arc of the solar chromosphere.
The brightest images, or strongest chromospheric emission lines, are due to Hydrogen atoms that produce the red hydrogen alpha emission at the far right and blue hydrogen beta emission to the left. In between, the bright yellow emission image is caused by atoms of Helium, an element only first discovered in the flash spectrum of the Sun.
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