A was idly wondering if it was possible to make a camera that showed live pictures of the past (as they happened not recorded) by sending a live feed very far away into space then beaming it back to Earth*. Ahh the joys of not sleeping ! Anyhow in my quest for the inevitable answer I came across this rather nice website.
Which is worth a look if you are interested in such stuff.
* Using the twin paradox for digital info rather than twins.**
** This Question is more than likely only possible due my complete and utter non understanding of Relativity.