Ok thats it.

You cannot travel back in time. Period. Going forward is highly questionable too, but time travelling ahead is the only way forward.

Think about it, with such super advanced type I civilizations in the universe and the possibility of intergalactic war with other races and from would be rime travelling their enemy time lines and destroying their foes, whilst they enemy does the same too, which would essentially cancel out all future existence of races.

You see how silly that sounds? Going back in time to eliminate the enemy race - it just doesn't and wouldn't happen otherwise some mad scientist would rule the world by now using a manipulated timeline.

More inconceivable that time travellers especially with cell phones, would return to a previous world line or timeline, and make wild predictions - some of which may or may not be true or was taken from part of an agenda known only to the priviliged few of that time, of future world events ( think Vonn Braun)

I suppose if we look at the georgia guidstones, once might surmise that that is a fuire worldline and that perhaps titor or some other starman from the future commissioned whilst being sqpped back to the eighties.