Concept of time travel is opposed by many paradox and prominently is Grandfather paradox.
Grandfather paradox first introduced by Rene Barjavel in the year 1943 in his book "The Imprudent Traveller"
The paradox says that if someone builds a time machine and goes in past and kills his own biological grandfather who is young and doesn't have children then in future, how are you born ???
This is a paradox and it explains two events connected with each other like killing grandfather and that person not taking birth
It is indeed complicated to solve this problem but the more appropriate solution seems to be different in my opinion
Since the first article I wrote on this blog on Nov 2008, I have been a firm believer that if a person happens to travel back in time and see his grandfather, he will not be able to kill him even if he fires the bullet.
Explanation,( in my views)
A person belonging to 21st century, travels back to 20th century i.e from 2010 to 1934 when his grandfather was very small and didn't have any children. He visits his grandpa's house and sees him of young age, perhaps younger than him. If the grandson decides to kill his grandfather and lifts up a pistol and fires then the bullet will not kill grandpa. Even the bullet will not come outside the pistol in that world. Reason is the bullet,grandson and all belong (born in late period i.e 21st century ). The grandson will just see his grandpa but he will not be able to talk with him,touch him and do any interaction with him. Its similar to a person peeping through a window of a house without the notice of the hose owner.
If time machine is created then people will be able to travel back in time and space but their time travel and presence will not affect daily life of people living in past.
So if a girl is working in kitchen and her grandsons make a time travel from future into the past, girl will not be able to see the grandsons and everything would be normal. Grandsons will see their grandma working in the kitchen but would not talk
In my opinion, another paradox arises
If the girl doesn't marry and doesn't have children then who will travel in time to see her claiming as grandson. So if I decide to travel in future and see my son's daughter then I might not do so since I don't have any child yet and if have don't know whether my son will have a daughter. HE MIGHT HAVE A SON
So is there any restriction in time travel?
Yes, if time travel becomes possible, then their will be restriction. You can't go anywhere in space and time as you wish. You can travel in past because you have some idea who your grandfather was but have no idea who your grandson will be
