Ask a random assortment of people if they would like to time travel,and if thet would prefer to go back or ahead in time,and you will probably get a pretty even split
Unfortonately there is bad news for those who would time travel.
Assuming that I should build a time machine in my basement,and offer free trips to anyone who fancies a jaunt.
Those who want to visit Queen Elizabeth1 to see if she really had wooden teeth(she didn't;they were just rotten and black)and the lead in her makeup was slowly poisoning her,so she was probably in a very bad humor most of the time) or to find out if King Ethereled the Unready really was unready(he wasn't his nickname is a mistranslation of an old English word meaning"bad advice" are going to be sorely disappointed
And why is that?Because you can't go back in time to where the time machine had not been invented.You just can't!
Your'e linking two different points in time,and the earliest of these points has to be the moment .at which the time machine came into existence.
Sorry,those are the rules.I don't make them.
So the reason why there are no visitors from the future is that nobody has yet managed to build a time machine in our own time.Either that or someone has built one and is keeping very quiet about it so that people don't keep knocking on his door
asking him if they can have a go on his time machine.(which would undoubtedly be annoying)
There is also the small matter of what is known as the "Grand Father Paradox"
What would happen if you went back in time and killed your grand father before your mom and dad were born?
Would you then cease to exist?
But the argument is that you are already in existence,as you were around to travel back in time,so if yo try to kill your grand father,you will obviously fail.
Hang on though!! Is it possible that you might just "pop"out of existence if you did manage to kill your grand father??
No,because that would imply two different realities,one in which you exist and the other in which you don't exist,which won't work at all.
This has led the eminent Professor Steven Hawkins to come up with the Chronology Protection Conjecture,a kind of virtual ban on time travel.Professor Hawkins that there must be a rule of physics to prevent time travel,because otherwise we would have tourists from the future visiting us,and people popping up willy nilly trying to kill their grand parents in order to prove a point
In the end though,if you are the kind of person who,at the first mention of time travel,brings up the possibility of killing your grand parents,then you are somebody who should not be allowed around time machines.
Or for that matter grand parents
In the end though,if you are the kind of person who ,at first mention of time travel
(from the book by John Connolly-"The Infernals"