Isaac Newton

Isaac Newton was born in Woolsthorpe, England, in 1643. His father died before he was born, and his early life included family difficulty and periods of isolation and study.

Newton later studied at Cambridge, where mathematics, natural philosophy, and astronomy became central to his work.

Newton wanted to understand why objects fall, why planets move, and why the Moon stays in motion around Earth.

His laws of motion and theory of universal gravitation helped connect motion on Earth with motion in the heavens, showing that the same physical principles could help explain both.

Gravity pulls objects toward Earth, but the Moon does not simply fall straight down because it also has sideways motion.

The Moon continually falls toward Earth while moving forward, producing an orbital path. Artificial satellites follow the same broad principle.

The Earth and Moon pages in TransitSatellite provide a direct way to connect Newton's ideas with objects users can explore.

A satellite in orbit is not beyond gravity. Gravity is continually pulling the spacecraft toward Earth.

The satellite also has horizontal velocity. It falls toward Earth while moving forward quickly enough that Earth's curved surface continues falling away beneath it.

TransitSatellite's orbital paths are modern visualizations of this relationship between motion, gravity, speed, and position.