Amazingly thought provoking

I am just watching this for the first time on Quest. I have to say I find this sort of thing my bag baby. It is way over my head but I like how it makes me think and question life as we know it. Stephen Hawking is one of my heroes, along with Winston Churchill and David Attenborough.

There are so many questions but what I would like to ask is what if there were civilizations millions or even billions of years older than ours, many light years away in space. What I want to know is, why is such a situation so hard for many people to believe possible? We have discovered planets that could support life even if they are too far away for US to ever reach.

Also, about worm holes and time travel - if the person who invented "time travel" was to use 2 worm holes to travel back in time and killed his/her old self before he invented time travel - that would not change the fact that he had already invented time travel - in order to go back in time to kill himself he had to have invented time travel! All that person would have done is kill his old self, the time traveling future self would still exist, the work he accomplished would still have occurred... the point in time when he invented time travel has already happened, killing himself would not change history but simply alter the future, surely? Even if he traveled back in time and killed his own mother before he was born - everything needed for him to be able to travel backwards in time has already happened...Surely it would only be impossible to travel into a future that hasn't happened yet?

It does my little brain in trying to think about this sort of stuff but I really like it.