Did you know that Doctor Who was broadcast in space from the very first episode, in November 1963? That signal is now 51 light years and some months away because the radio waves are traveling with the speed of light. Is heat the key to finding extra-terrestrial life? And more importantly are their aliens out there somewhere watching An Unearthly Child? Brian Cox investigates in the video below.
The first part is here:
https://www.youtube.com/watch?v=e-gOvMJOTHs
