speed of light travel times. We definitely need to fold space/time to create wormholes to get to where we want to go.
How Radiation in Space Poses a Threat to Human Exploration.
Andromeda Galaxy ~ a massive spiral, 2.5 million light-years away, over twice the diameter of our own Milky Way, it's the largest nearby galaxy. Its population of bright young blue stars lies along its sweeping spiral arms. (Spitzer Space Telescope)