The speed of light is too slow for interstellar travel, and the amount of energy required is infinite.........
In 1968 Freeman Dyson calculated that there “Momentum Limited” spacecraft using atomic pulse propulsion could reach Alpha Centauri in 133 years.
“The biggest design above is the “super” Orion design; at 8 million tonnes, it could easily be a city.[12] In interviews, the designers contemplated the large ship as a possible interstellar ark. This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after.”
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)#Theoretical_applications