Relativity’s Time Warp to Andromeda

The craziest thing I learned in astronomy is this: Distances shrink when you travel

close to the speed of light. Let’s say you fly to the Andromeda Galaxy,

just 2 million light-years away. We build you a spaceship that goes almost at light speed.

From your perspective, that massive distance shrinks to just 3 light-years. So for you,

the trip takes 3 years. You visit aliens. You fly back. Total travel time?

Under 7 years. But when you return to Earth… you’re horrified. 4 million years

have passed. Earth watched you fly away for 2 million years… then waited another

2 million years for you to come back. This isn’t science fiction.