Physics- orbital Mechanics

Key Figures

Ptolemy (100-169 AD)

published a detailed model of a geocentric universe that became the established authority not eh subject until Renaissance times.

Niccolas Copernicus (1473-1543)

published a heliocentric model that eventually replaced earlier geocentric models

Gallileo Galilei (1546-1642)

produced evidence supporting the Copernican model.

Tycho Brahae (1546-1601)

Gathered very accurate data on the motion of the planets which led to further discoveries

Johannes Kepler (1571-1630)

Used Brahe’s data to accurately describe the motion of satellites in an orbital system.

Isaac Newton (1643-1727)

explained gravity as a universal force acting between all objects, from apples on earth to the motion of the moon and planets.

Henry Cavendish (1731-1810)

Determined the value of the universal gravitational constant, G which opened the ability to quantify gravitational force determine masses of planets and stars.

perihelion

the closest point to the sun in a planets orbit

aphelion

the furthest point to the sun in a planets orbit

semi-major axis

half the distance across the longest axis of the ellipse