History of Gravitation

What was Aristotle's view of the universe?

Aristotle believed in a geocentric model where the Earth was stationary at the center of the universe, with planets and stars orbiting it in perfect crystalline spheres.

What was Ptolemy's view of the universe?

Ptolemy developed a geocentric model that placed Earth at the center, explaining planetary motion through complex systems of epicycles and deferents to account for observed retrograde motion.

What was Copernicus's view of the universe?

Copernicus proposed a heliocentric model where the Sun, not the Earth, was at the center of the universe, and planets including Earth orbited the Sun in perfect circles.

What was Tycho Brahe's view of the universe?

Tycho Brahe supported a geo-heliocentric model where the planets orbited the Sun, but the Sun and Moon still orbited a stationary Earth.

What was Kepler's view of the universe?

Kepler refined the heliocentric model by proposing that planets orbit the Sun in elliptical paths, described by his three laws of planetary motion.

What was Galileo's view of the universe?

Galileo was a strong proponent of the Copernican heliocentric model, providing observational evidence through his telescope, such as the phases of Venus and Jupiter's moons, that challenged the geocentric view.

What was Newton's view of the universe?

Newton unified celestial and terrestrial mechanics with his Law of Universal Gravitation, explaining that the same force causing objects to fall on Earth also governs the orbits of planets around the Sun.

What is the Law of Universal Gravitation?

The Law of Universal Gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Its mathematical expression is F = G \frac{m1 m2}{r^2}.

What is the mathematical "inverse-square law"?

The inverse-square law describes any physical law where a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity. For example, in gravity, light, and sound, intensity often decreases with the square of the distance.

What does heliocentric mean?

Heliocentric means 'Sun-centered,' referring to a model of the solar system or universe where the Sun is at the center and planets, including Earth, orbit around it.

What shape are planetary orbits really?

Planetary orbits are really elliptical, not perfect circles.

Why did Copernicus wait until his deathbed to publish his book "On the Revolution of Heavenly Orbs"?

Copernicus waited until his deathbed to publish "On the Revolution of Heavenly Orbs" likely due to fear of controversy, ridicule from the scientific community, and potential persecution from the Church for challenging the long-established geocentric view.