The Halley Comet

c.350 BCE

According to Aristotle, comets are a type of weather phenomenon that occur in the upper atmosphere of the planet.

1577

Tycho Brahe determines that a comet he has seen must be located far from the atmosphere of Earth.

Tycho Brahe

In 1577, he determines that a comet he has seen must be located far from the atmosphere of Earth.

1758

Comet Halley makes a comeback after 76 years.

Comet Halley

In 1758, this makes a comeback after 76 years.

1819

Johann Encke, a German astronomer, finds a second periodic comet that returns once every 3.3 years.

1950

Jan Oort, a Dutch Astronomer, he suggests that there is a vast cloud of comets surrounding the solar system and that stars could cause these comets' orbits to be disturbed.

Jan Oort

A Dutch Astronomer, he suggests that there is a vast cloud of comets surrounding the solar system and that stars could cause these comets' orbits to be disturbed.

Johannes Kepler

a former pupil of Brahe, thought that objects moved in straight lines.

Johannes Hevelius

a Polish astronomer, hypothesized that a comet from 1664 had followed a curved orbit around the sun.

parabola

However, these ellipses were so stretched out that they could be approximated to an open-ended curve known as a _____.

1684

In ______, Edmond Halley visited Newton. He was eager to talk about the potential causes of the motions of comets and other heavenly bodies, including planets.

Philosophiae Naturalis Principia Mathematica

Their encounter ultimately resulted in Halley editing and funding the 1687 publication of ________, Newton's significant work on gravity and the laws of motion.

Astronomiae cometicae synopsis

Halley published ____________ in 1705, which contained an outline of his theories.

gravitational pull

Halley believed that the _____ from Jupiter and Saturn could slightly alter the comet's trajectory and cause a delay in its timing.

Alexis Clairaut, Joseph Lalande, and Nicole-Reine Lepaute

They spent several grueling months recalculating when the comet might reappear and where it might first be seen in the night sky as the year of the comet's predicted return drew near.

Johann Palitzsch

A German farmer and amateur astronomer, made the discovery of the Halley’s comment return on December 25, 1758.

Nicolas-Louis de Lacaille

a French astronomer, gave the comet the honorary name Halley's comet in his memory.

1986

In ______, a spacecraft made a close approach to the comet, collecting information on the composition of its nucleus and tail.

1680

Newton examined and anticipated the future course of the _____ comet using his new theory.