The Cosmic Engine. Mercury. Planets. Venus. Earth. Gravity. Mars. Powered by nuclear reactions. Sun is a star. Jupiter. Solar System. Saturn. Uranus. Neptune. Millions of stars (suns). Milky Way. Stars orbit galactic centre. Galaxy. Gravity. Billions of galaxies. Universe.
Powered by nuclear reactions
Sun is a star
Millions of stars (suns)
Stars orbit galactic centre
Billions of galaxies
Universe is expanding
Up until 200 years ago, it was all about the solar system.
1500 year battle over geo-centric vshelio-centric
Geo-centric: Geo = earth Centric = centred around
Everything revolved around the Earth
Helio-centric: Helio = sun Centric = centred around
Everything revolves around the sun
Aristotle: Philosopher – Sun, moon, planets & stars orbit Earth on crystal spheres
Geo – centric
Aristarchus: Philosopher – Earth & planets orbit the sun on crystal spheres, stars are on a fixed sphere very far away.
It explained retrograde motion of planets
Based on evidence, not philosophy
It became part of religious doctrine
Helio-centric model – Earth & planets orbit the sun on crystal spheres
It was simpler, and possibly more “correct”, but it didn’t work any better, therefore it was largely rejected.
Also rejected for religious reasons