A Billion Light-Years Away: The Technologies That Could Take Us There A Billion Light-Years Away: The Technologies That Could Take Us There The Andromeda Galaxy — 2.5 million light-years away, and still less than 0.3% of the way to one billion. Credit: Adam Evans / Wikimedia Commons (CC BY 2.0) 📱 Space Technology Encyclopedia — Explore warp drives, light sails, and the physics of interstellar travel in our free app. Download Free One billion light-years. Not a billion miles, not a billion kilometers — but a billion years of travel at the fastest speed the universe permits. To frame that scale: our entire Milky Way galaxy spans just 100,000 light-years. Our nearest large galactic neighbor, Andromeda, sits roughly 2.5 million light-years away. One billion light-years launches us deep into a universe of superclusters, cosmic voids, and structures so enormous they barely have names in ev...
