World Wars and the AtomScience & Math The expanding universe 1929Turning point Edwin Hubble finds galaxies moving away from us: the universe is expanding. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → Habitual fire and cooking → Homo sapiens appears → Complex language → Natufian villages → Oldest known bread → Agriculture begins → Irrigation → Uruk and the first cities → Cylinder seals → Writing (cuneiform) → Babylonian mathematics → Babylonian astronomical diaries → Thales and natural philosophy → Trial and death of Socrates → Plato's Academy → Aristotle's Lyceum → Alexander's conquests → Alexandria founded → Library of Alexandria → House of Wisdom → Ibn al-Haytham's Book of Optics → Bacon's Novum Organum → Royal Society → Papin's steam digester → Newcomen steam engine → Watt's steam engine → Thermodynamics → Entropy → Quantum hypothesis → Special relativity and E=mc² → General relativity → The expanding universe Community notesLoading notes… Learn more ranked by votesDocumentdoi.orgHubble (1929), A relation between distance and radial velocity (PNAS) ↗Editor's pickDocumentbritannica.comHubble's law (Britannica) ↗Editor's pickBookMarcia BartusiakThe Day We Found the Universe ↗Editor's pickVideoSearch on YouTubeHubble expanding universe discovery ↗Editor's pick