Reply to post: Re: Faster than light not needed?

Re: Faster than light not needed?

"470 light years might be achievable in a human lifetime when we have a method of propulsion which uses very little fuel."

Yes, this is entirely possible, once you have the necessary propulsion technology.

Time dilation at relativistic velocities (slowing of time relative to a static observer) is exponential at constant acceleration, so once you have a ship that is capable of constant 1G acceleration*, you can reach the nearest star in less than a decade, cross the Milky Way in around a decade, reach the nearest major galaxy (Andromeda, ~2.5 million light years away) in a few decades, and reach the edge of the observable universe within a human lifetime.

These are local ship times, obviously. To anyone not on the ship it would take tens / thousands / millions / billions of years for it to complete those journeys.

*_{Constant acceleration as experienced by the ship's crew. A static observer would see the ship's acceleration tending towards zero as it approached c (light speed.)}