NavList:

George H wrote:

"As for other galaxies, to get to the Andromeda nebula M31, visible with the
naked-eye, travelling at the speed of light, would take over 2 million
years. So even if we could travel at the speed if light, it's not on."

 

Well, it stinks if you want to be famous back home for your amazing discoveries, but if you don't mind heading out with no connection to your past, time dilation cures all. At 99% of the speed of light, time aboard ship would slow by a factor of 7. So for shipboard passengers, the trip would only take 290 thousand years. Hmmm... Still stinks. Ok, let's crank it up to 99.99% of c. That raises the time dilation factor to 70.7 so the trip would take merely 29 thousand years. Every "pair of nines" in that fraction of c adds a factor of ten to the time dilation so to get the journey down to less than three years of shipboard time, we would need to travel at 99.99 99 99 99 99% of the speed of light. You age three years aboard ship, everything else ages two million years (time dilation factor is 1000000/sqrt(2)). Now all we need is the wealth of a thousand star systems to buy the fuel for the ship, and we're ready to go. I've got it... we'll save money by navigating using a sextant! No wait... aberration at that speed would squish all the stars and all the galaxies into a tiny dot directly ahead of us. No stars visible for celestial navigation at all...