Despite his many achievements, it is arguable that the most important factor influencing the legacy of Edmund Halley is his friendship with Newton.
He encouraged Newton to undertake the ‘Principia’ in the first place; he went on to edit and proof read the text, write the preface and to finance its publication in 1687.
Had Edmund Halley not been born, his comet would still exist, albeit under a different name. Newton’s Principia, at least in the form the world knows it today, almost certainly would not.
Halley was a prolific mapmaker, showing prevailing winds, tides and magnetic variations in his cartography.
‘A typical comet has three parts: a frozen central part called the nucleus, a fuzzy cloud surrounding the nucleus called the coma (or head) and a tail consisting of gas and dust. The nucleus, usually only a few kilometres across is made of grains of frozen water, methane, ethane, carbon dioxide, ammonia and other gases’
Whipple coined the phrase ‘dirty snowball’. In 1986 the European Space Agency‘s craft Giotto proved that Whipple’s theory is fairly accurate when it took close-up photographs (from a distance of 480 kilometres) of the nucleus of HALLEY‘s comet.