Astronomy Section

Nelson Science Society: Astronomy Section,
Thursday November 2nd, 7:30pm
Milton Room, Cawthron Institute. (The Milton Room is in
the building located at the SW corner of the junction of Milton Street
and Halifax Street.)

ECLIPSES IN HISTORY, a talk by Duncan Steel

Summary: Eclipses of the Sun and the Moon have proven to be pivotal events in history, sometimes through superstitious beliefs and at other times through the superior understanding of scientific cultures. Christopher Columbus used prior knowledge of a lunar eclipse to persuade the natives of Jamaica to feed him and his men in 1504. In contrast, the British military disasters in the battles of Isandlwana and Rorke’s Drift (as depicted in the movie ‘Zulu’) on 22nd January 1879 might have been avoided if they had known how the Zulus would react to the partial solar eclipse which occurred that day. The preceding year, Edison got
the idea for the electric light bulb during an expedition to observe a solar eclipse in Wyoming. Inspired by a lunar eclipse, Alexander the Great’s army defeated the Persians at the Battle of Gaugamela in 331 BC, altering the course of history. Many other battles have been affected in
a similar way.

Eclipses are also of huge scientific and chronological value. Historians have been able to fix the years when different events occurred through back-calculations of eclipses mentioned in ancient texts. Chinese records of eclipses have enabled scientists to determine how the spin
rate of the Earth (and therefore the length of the day) has changed over the past few thousand years. Einstein’s General Theory of Relativity was demonstrated to be correct through stellar observations made during an eclipse in 1919. The inert gas helium was first identified in 1868, in a spectrum of the solar atmosphere observed during an eclipse, hence the name of the element (from Helios, the Greek word for the Sun).

Dr Duncan Steel is the author of ECLIPSE: The Celestial Phenomenon Which Changed the Course of History (Headline, London, 1999 and 2000; National Academies Press, Washington DC, 2001).