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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.
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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 Universe is expanding
Scale of the Universe http://primaxstudio.com/stuff/scale_of_universe/
A Little History 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
It all started with Aristotle & Aristarchus ~330BC Aristotle: Philosopher – Sun, moon, planets & stars orbit Earth on crystal spheres Geo – centric ~240BC Aristarchus: Philosopher – Earth & planets orbit the sun on crystal spheres, stars are on a fixed sphere very far away. Helio– centric
Claudius Ptolemy - ~120AD Geo-centric It explained retrograde motion of planets Based on evidence, not philosophy It worked! It became part of religious doctrine
Nicholas Copernicus 1473 - 1543 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