Mild of Historical past | by Brian Koberlein



21 October 2019

Aurora as seen from Iceland.
Moyan Brenn, through Wikipedia, cc-by-2.0
Aurora as seen from Iceland.

People have all the time been astronomers. Now we have appeared to the night time sky in marvel, and have recorded what we noticed for hundreds of years. However usually these information are misplaced to time, and even once we do have information the descriptions recorded aren’t all the time clear.

Most of the early astronomical recordings now we have mark important occasions. Issues resembling eclipses or new stars (supernovae) showing within the sky. However a brand new paper in The Astrophysical Journal Letters exhibits the report of one thing far more refined: the rippled colours of the northern lights.

Y. Mitsuma’s tracing of the photographs of H. Hayakawa.
Y. Mitsuma and H. Hayakawa
Y. Mitsuma’s tracing of cuneiform tablets.

The authors describe three Assyrian and Babylonian cuneiform tablets. These tablets date from 680 to 655 BCE and describe purple clouds or a purple glow within the night time sky. It is a widespread look of aurora, and the outline is just like Babylonian recordings relationship from a century later. It appears to be the earliest recording of the northern lights.

Whereas the Assyrian Empire was a lot additional south than northern lights are usually seen right this moment, on the time Earth’s north magnetic pole was a lot nearer to the area. Sightings of aurora would have been extra widespread then. Nonetheless, the outline of a “purple glow” is relatively imprecise, so the authors additionally appeared to scientific information as properly.

The northern lights seem strongly when photo voltaic exercise is excessive. Because the Solar releases excessive vitality particles that create aurora, these particles may work together with nitrogen within the air to supply carbon-14. When the Solar is especially lively, information of that exercise could be present in elevated carbon-14 ranges in issues resembling tree rings. The authors famous that tree rings from about 660 BCE present elevated carbon-14, which agrees fairly properly the cuneiform tablets.

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