Astronomer — Edmond Halley (1656–1742) was an English astronomer, mathematician and geophysicist, the second Astronomer Royal of England. As a young man he compiled at Saint Helena the first catalogue of the stars of the southern sky. Applying the newly-formed theory of universal gravitation, he studied the orbits of comets and predicted that the comet observed in 1682 would return roughly every 76 years: the comet now bears his name, Halley’s Comet. He was decisive in the birth of modern science because he encouraged, and personally financed, the publication of Isaac Newton’s Philosophiae Naturalis Principia Mathematica (1687). He also worked on terrestrial magnetism, tides and demographic statistics, and proposed using transits of Venus to measure the Earth–Sun distance.

Theories and contributions

  • Halley’s Comet — First prediction of the periodic return of a comet (period of roughly 76 years) based on Newtonian gravitation.
  • Transits of Venus — Proposed exploiting transits of Venus across the solar disc to measure the solar parallax and hence the Earth–Sun distance.
  • Patronage of the Principia — Financed and oversaw the publication of Newton’s foundational work, making the spread of classical mechanics possible.

Linked atoms

2 linked atoms.

02 Forze e leggi di Newton

08 Gravitazione universale