The Tyranny of Distance
Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. To get to our nearest neighbor, Proxima Centauri (4.2 light years), takes wildly different times based on your tech.
The Vehicle Tiers
- Chemical Rocket (Apollo): Max speed ~25,000 mph. Time to Alpha Centauri: 70,000 Years.
- Nuclear Pulse (Orion): Detonating nukes behind the ship. Max speed ~5% light speed. Time: 85 Years.
- Fusion Ramjet: Scooping hydrogen from space. Max speed ~50% light speed. Time: 9 Years.
- Warp Drive: Breaking physics. Time: Minutes.
Time Dilation
As you approach the speed of light (c), time slows down for you relative to Earth. At 99.9% of c the Lorentz factor is about 22, so a 4 year trip for you is about 89 years for the friends you left behind. This tool calculates both the "Ship Time" and "Earth Time."