Shadow bands

History

• In 1820, Hermann Goldschmidt of Germany noted shadow bands visible just before and after totality at some eclipses.

• In 1842, George B. Airy, the English astronomer royal, saw his first total eclipse of the Sun. He recalled shadow bands as one of the highlights: "As the totality approached, a strange fluctuation of light was seen upon the walls and the ground, so striking that in some places children ran after it and tried to catch it with their hands."

• In 1905, Catherine Octavia Stevens observed shadow bands at the start of the total eclipse of August 30 at Cas Català, Majorca. "As to the character of their appearance and mode of progression, it was observed that they swept along with a flight that was at once rapid and orderly, there was no confusion of the wavy lines with one another, but all bore along in one and the same direction in parallel formation, traversing the ground as water-wave reflections may be seen to do on the under surface of a boat, only that there seemed in the case of the shadow-bands to be a more distinct expression of a forward movement." Clouds prevented observations after totality.

• 22 years after observing the same eclipse from Zaragoza, the British amateur astronomer Percy Mayow Ryves wrote in the Monthly Notices of the Royal Astronomical Society that the experience had convinced him 'that the shadow bands were the result of light from a very small source, a small segment of the Sun’s disc, revealing the irregularities of density in the atmosphere, in a manner similar to that in which the irregularities in the glass of a window pane are revealed by the light of the planet Venus.'

• In 2008, British astrophysicist Stuart Eves speculated that shadow bands might be an effect of infrasound, which involves the shadow of the Moon travelling at supersonic speed and inducing an atmospheric shock wave. However, astronomy professor Barrie Jones, an expert on shadow bands, stated, "The [accepted] theory works; there's no need to seek an alternative."

• In 2024, students at the University of Pittsburgh devised an empirical test to collect evidence for both the atmospheric turbulence theory and Eves's moon slit theory. The test of atmospheric turbulence involved using a high-altitude balloon with weather instruments to measure relationships between humidity, temperature, and barometric pressure in the atmosphere and the shadow bands on the ground. The test of the alternative theory involved sending another high-altitude balloon 90,000 feet above Concan, Texas to detect light patterns indicating shadow bands outside of the atmosphere.

References

References

1. [http://www.earthview.com/tutorial/effects.htm Effects During a Total Solar Eclipse] {{webarchive. link. (2012-07-30)
2. J. L. Codona. (1986). "The Scintillation Theory of Eclipse Shadow Bands". Astronomy and Astrophysics.
3. Jones, Barrie. "Explanation from Barrie Jones, Open University".
4. Strickling, Wolfgang. (2007-01-26). "Wolfgang Strickling's eclipse observations 2001 page".
5. (1999). "Total Eclipses: Science, Observations, Myths and Legends". [[Springer Publishing]].
6. (1998). "The Sun in Eclipse". [[Springer Publishing]].
7. (1857). "Memoirs". [[Royal Astronomical Society]].
8. M. Littmann, K. Willcox, F. Espenak: Totality: eclipses of the sun 2nd edition. Oxford University Press. p. 119
9. Stevens, Catherine O., The Problem of "Shadow Bands", ''Journal of the British Astronomical Association'', Volume 16, No 2, 1906, pp60-62
10. Mobberley, Martin. (2017). "Percy Mayow Ryves (1881-1956): Observer, discoverer & BAA Section Director". Journal of the British Astronomical Association.
11. Ryves, Percy. (1927). "Note on the Shadow-Bands". Monthly Notices of the Royal Astronomical Society.
12. Jones, Barrie W.. (1999). "Shadow bands during the total solar eclipse of 26 February 1998". Journal of Atmospheric and Solar-Terrestrial Physics.
13. (May 21, 2008). "Sound 'cause of shadow spectacle'". [[BBC News]].
14. (2024-04-06). "Scientists get another chance to study a solar eclipse mystery".