What is the version of the following sentence with correct punctuation?

One consolation however may be the socalled twin paradox which means that if you travel at the speed of light time stands still Relativity theory suggests however that if you travel faster than light then travels back in time
One consolation however, may be the so-called twin paradox, which means that if you travel at the speed of light, time stands still. Relativity theory suggests, however, that if you travel faster than light then travels back in time.