Edmund Halley : 1656-1742
One of the household names of astronomy because of the
great comet whose 76-year periodicity he was the first
to discover. His contributions to meteor science were
also of great significance - positively and negatively.
In March of 1719, a huge meteor fireball, or bolide, was seen over much of England. Halley gathered reports from observers at widely separated locations from which he deduced by triangulation that "they abundantly evince the height thereof to have exceeded sixty English miles." This enabled him to estimate the velocity of the fireball which he found "incredible", since it was "above 300 such miles in a minute ." This made Halley one of the first (he was preceded by Montinari, in Italy) to discover how high and how fast meteors travel when entering the atmosphere. This led to a great surge of interest in meteoric studies.
However Halley's discovery immediately posed a problem for him. Many witnesses had reported "hearing it hiss as it went along, as if it had been very near at hand." He knew that sound takes five seconds to travel an English mile, so he could imagine no way that the witnesses could instantly hear any sound directly from the fireball. He therefore dismissed the reports as "the effect of pure fantasy", a judgement which bedevilled the subject for a further two and a half centuries.
One may to some degree excuse Halley because the existence of radio waves able to transfer the necessary energy was not demonstrated until 1888, by Heinrich Hertz. A more prudent judgement was delivered in 1784 by Dr Thomas Blagdon, secretary of the Royal Society, who collated reports of another large meteor fireball which crossed England from Scotland to the Continent. As in 1719 there were many reports of simultaneous sounds, which perplexed Blagdon. He was so convinced of the veracity of the witnesses that he did not reject the anomaly and wisely decided that he "would leave it as a point to be cleared up by future observers ." However he followed Halley to the extent of suggesting that the sound perception was psychological through "an affrighted imagination".
These conclusions, by two eminent men, created a "Psychological Red-herring" which led meteor scientists on a rewardless chase until the electrophonic explanation was eventually developed by me in 1979.
