Is it possible for a human being who has a life expectancy of 70 years to make a round-trip journey to a part of the universe thousands of light-years distant?
Yes, in principal, by traveling close to the speed of light (c). Time, including biological processes, can be slowed by a factor of 1/sqrt(1 - (v/c)^2), according to the theory of relativity, which deserves to be called a law by now. The problem will be a high probability of a catastrophic collision with a small object along the way.
