The question has been protected on stackoverflow, so answering here. Yes a mirror 13.5 light years away can do the trick. But there is some fundamental lack of

The question has been protected on stackoverflow, so answering here. Yes a mirror 13.5 light years away can do the trick. But there is some fundamental lack of understanding regarding relativity that has lead to such a question. In fact, the top answer is incorrect on several levels. 1. Technically the only way a person can travel 27 light years in 27 years is by travelling through out at the speed of light. Ignoring the infinite amount of energy required for such travel, there is another aspect of such travel that is not being considered. Time Dilation. So assuming you were born and take off at the speed of light. Yes you will be able to observe your birth on earth 27 years later, but you would still be a baby and not 27 years old. Time would have been effectively frozen for you as you traveled. 2. The top answer says that you are always viewing and hearing the past. You are hearing the past, but you are actually viewing the present. The light radiating out of an event you are observing are also causality horizons. In your reference frame you are observing past events depending on the distance. However thanks to relativity and Lorentz contraction, there are reference frames where the distance between you and the event can be arbitrarily close to zero, effectively making the events simultaneous i.e. when you see an event you are effectively watching it as it happens simultaneously, you are not watching the past. This is also an alternative explanation for 1. i.e. the baby cannot grow older if you put it 27 light years away in 27 years time. It will be able to watch its birth, because its only just been born. http://en.wikipedia.org/wiki/Minkowski_diagram http://en.wikipedia.org/wiki/Minkowski_diagram