With known physics we could do interstellar travel: http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)#Interstellar_missions http://en.wikipedia.o

With known physics we could do interstellar travel: http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)#Interstellar_missions http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsi... It would be unbelievably expensive right now however. But give it a century or two and things could well change. If a space elevator was built it would slash the cost.