Catching up.

The bad news is: "time flies". The good news is: "you're the pilot".

--Michael Althsuler

If there is a direct relationship between the past of the sender and the future of the receiver, then a change caused by a message received might ripple 'back' to the time of the senders. This might be hard to believe. It would mean that after receiving the message in the past, the world of the future scientists would be corrected immediately. Buildings, cities, works of art etc will cease to exist because the people who ones built them might never have been born. Other works might suddenly be standing there instead.

A change in history might cause a correction that immediately '- zips -' through time as a wave and corrects the present time of the scientists.

The consequence of a critical change might wipe out the civilization of the scientists and might result in a paradox. This type of paradox is referred to as the "Grandfather Paradox". Namely, you go back in time and kill your grandfather before your parents are born. Thus, if your parents are never born, you could never be born. But if you were never born, you couldn't have killed your grandfather. But if you hadn't killed your grandfather, you would've been born. And so on.

The grandfather paradox is often referred to when talking about time travel but it applies equally to sending messages to the past that causes the existence of prophecies that potencially change the course of history.

This type of relationship between future and past is difficult to understand.