Question

How long would it take to travel to another galaxy?

Answer 1

It depends...

Explanation:

There are some small satellite galaxies of the Milky Way galaxy, but let's consider our largest neighbour in the Local Group, namely the Andromeda Galaxy.

This is situated approximately `2.5` million light years away.

That means that from the perspective of the people who stay at home, a round trip would take at least `5` million years.

Note however, that the traveller(s) could experience significantly less time, if they travel with sufficient speed.

For example, if they used a spacecraft that accelerated constantly with an acceleration of `1`g (i.e. `9.8 ms^(-2)`) for about `14` years (ship time), then decelerated at `1`g for about `14` years, that would be sufficient to travel from our galaxy to the Andromeda Galaxy.

Returning home the same way, the traveller(s) would experience another `28` years of time, but arrive home to find that `5` million years had passed.