My query is this. In the twin paradox lets assume that one twin Barbara keeps on moving at a relative speed of "c" away from the stationary earth twin Alex. If I were to be able to be at both Barbara's rocket and the earth at the same instant ( meaning I could travel through space instantaneously ) would I actually see any difference in the ages of the two twins. Which then gives rise to the question Lets say we on earth know this planet XEON to be 20light years away from us. Lets say we have a twin on earth Alex and another twin Barbara moving at speed of light "c" towards the planet and away from earth. Lets assume the twins meet at an event "p" on the surface of earth. At that event both twins are of the same age and exactly same physical condition. From this event "p" onwards Barbara is moving towards the XEON, while Alex stays behind on earth. A doctor has give both Alex and Barbara 10 years to live from event "p" Now Alex knows that he will die in 10years and so will Barbara . I assume he can claim that there is no way Barbara can reach the planet XEON alive since she will take 20 years but she will be dead in 10years. Is it possible for Barbara to reach planet XEON alive or will she die before she reaches it ?