Time Travel is the dream of the ability to travel to a different point in time than our own and to investigate (e.g. Find out who exactly Jack the Ripper was) or change the an event (e.g. Prevent World War I by preventing the assassination of Archduke Franz Ferdinand). Whilst we are all time travellers, always moving forward in time, we long to be able to jump back and forth in time.
Time Travel is possible but its only an one way mission according to Prof. Brian Cox, a British Academic and Television Presenter 1. Time Travel is possible based on Albert Einstein's theory of Special Relativity. Time travels slower when you travel faster, so if you were to travel near to the speed of light, visit a far off star and come back, your time might seem to be five years but on Earth, your friends may have aged more than fifty years. This theory is the basis behind the 2014's smash film Interstellar. According to Einstein only light photons can travel at the speed of light because they don't have mass.
It could be argued that as light travels at the speed of light, light could in fact be Time Travellers. Although it takes about 8 minutes to get to the Earth, the light could have set off more recent than the calculated time.
Scientists at Queensland University have proven that its possible for two particles to travel into time using a wormhole, the below video should help you out.
If what Dr. Luke Butcher is correct, next weeks Lottery numbers are coming down the wormhole. Wormholes as well as being portals to other parts of the milky way or the universe could be portals to different times.
What is to stop you from travelling back in time and assassinating your Grandfather for instance. If your Grandfather died before your parent was conceived then you can't be born and if you can't be born, you can't travel back to kill him. Prof. Stephen Hawking argued in one of his programme was that if Time Travel from the future to the past was possible then why had we not been visited by Time Travellers.
Suppose you managed to travel back in time and change some ever so slight but in reality, the change could have enormous consequences. In Blackadder Back and Forth, a comical approach to Time Travel, Blackadder meets with William Shakespeare and punches him on behalf of everyone forced to study his plays, when back in the present, he discovers the presence has changed considerably. A small change in the past can have a ripple affect and not the desire effect that you had hoped for. The Butterfly Effect comes from the most minor event that could ripple and eventually cause something bigger. The Back to the Future films lightly touch on the Butterfly Effect when changes that McFly have caused result in his siblings disappearing from a family photo until his father changes his mind and comes to his girlfriends assistance. Even travelling back and changing an event during the dinosaurs and Prehistoric Animals time period could affect the time now. You wouldn't be able to prevent the dinosaurs being wiped out but you could affect an event later down the line.
According to some calculations, Russian Cosmonaut Sergei Krikalev has actually travelled into The Future more than anyone else. Before jumping with glee than you can jump into the future, discover next weeks lottery numbers and come back, it should be noted that he has only travelled 0.02 second into the future. The reason for the time travel is based on the amount of time he has spent in space, 803 days 9 hours and 39 minutes. He has spent more time in space than anyone else from Earth. 2
One of the most famous time machines is the space ship that belongs to The Doctor of Doctor Who fame and this is the TARDIS, a space ship that is disguised as a Police Box. The Tardis only looks like a Police Box because it was damaged whilst disguised as a Police Box and the Doctor has not yet repaired it. At the heart of the TARDIS is a star that it about to go supernova which produces such a massive amount of energy that enables the Tardis to fly. A space ship that has a massive star at its core and appears like a normal police box, you need to suspend your believability and just enjoy.