| The chronological differences between past and present in time travel are marked. |
| Then, as an old man, he decides to make his final trip back to the past and give the secret of time travel to his youthful self. |
| Since we have never seen a tourist from the future, time travel must be impossible. |
| You both are goddesses and enchantresses, and the three powers you share are thought speak, telekenisis and time travel. |
| And it is science fiction about time travel, so you need to keep your wits about you. |
| In fact, considerable evidence posits that time travel is impossible, he said. |
