Right now you are traveling at about 230 kilometers per second as the solar system orbits the center of the Milky Way, yet a single lap still takes roughly 225 million Earth years. This episode adopts that galactic year as a new yardstick for deep time, explaining why billion-year scales squish major events together while million-year scales produce numbers too large to feel.

Using this clock, the hosts place the Big Bang at 61 galactic years ago, the birth of the Milky Way at 60, a hypothesized merger with the Kraken galaxy at 39, and the formation of the Sun and Earth at 20. They trace the long slog from prokaryotes at 16 galactic years ago through the Great Oxidation Event, eukaryotes, multicellular life, and the first land plants, then the sprint through the Cambrian explosion, the Permian-Triassic extinction exactly one galactic year ago, the dinosaurs’ demise at 0.3, and modern humans at just 0.001. The timeline then runs forward through a new supercontinent, the end of total solar eclipses, the collapse of photosynthesis, the Andromeda collision, and a lonely mega galaxy 2,000 galactic years from now.

• Why the Milky Way spun for over 40 galactic years before our solar system existed
• Why oxygen had to rust the oceans before it could build up in the atmosphere
• How the Sun’s bobbing path through the galactic plane may be linked to mass extinctions
• Why tidal acceleration will eventually push the Moon too far away to fully cover the Sun
• How dark energy will carry every galaxy outside the local group beyond the cosmic event horizon