Debate Is time travel possible?

[Nottus]

Here's an example. Say you start on world line Beta where the world is like what it is now. Then you go back and kill your grandfather***, then after you kill your grandfather, the world lines will diverge, and you will be on world line Alpha. It will be a wholly different world line where your grandfather got mysteriously killed by someone, and a world where 'you' don't exist, but you can still be on the world line because you are from world line Beta, and therefore, is a different person because your grandfather still exists on world line Beta. No paradoxes necessary.

*** Connor Stein also stated that you can only send information back in time, so you can only send a memory (send information back in time) of trying to kill your grandfather back in time in order to create a virtual body, which uses that memory to execute the task.

 

[Nottus]

I would like to think that time travel will become possible, but we then have Fermi's Paradox (yes I know I use that one a lot....) If it is possible, why have we not seen a royal visit, or presidential visit from the future?

Firstly, the reason why we don't receive a 'royal visit' is because the moment they visit us, they will be 'visiting' us on another world line, therefore we do not have a visit unless it is predestined on our world line that there will be one. Secondly, time travel isn't as simple as putting someone's ass on a vehicle and pressing the button. It involves taking a portion of a person's memory and sending it back by laser. A person would never fit in a mini-singularity.

 

[Phil Wainwright]

I think I understand the theory (or theories) of time travel. I do struggle with some of the advanced maths, and in some cases I have to let others show the way there. I used to struggle with complex maths, and never really fully understood the calculations behind J (mathematicians refer to the number I, but as this is current in electronics, we tend to refer to it as J. It is in effect the square root of -1)

I am looking forward to the completion of the test rig I am developing, but at the same time I do enjoy 'Thought Experiments' as the Great Man referred to them. This also includes Fermi's paradox. Yes you are correct that he was a mathematician, but his paradox was used to argue against the Drake equation..... essentially "if there are so many alien civilisations, why have we not seen any of them?"

Therefore logically the paradox must also apply to time travel. Just as a thought experiment. But yes, you are right, it is all based on numbers.......

As far as whether it is possible or not to achieve time travel, I do not want to open discussions on rotating scintillating spangled vortices or whatever the mathematicians amongst you call the fields. I want to begin a series of experiments that will hope to physically achieve the theory. I want glowing green fogs on my workbench, I want my scale model to vanish whilst floating on an aquarium leaving nothing but the indentation of the hull in the water..... I want to compare times from inside and outside the fields. Basically, I want absolute incontrovertible proof that it is possible. I know I will need the help of others to achieve this, but to begin with, I need a little more money (got to keep working at the minute) but hopefully, my latest invention goes commercial on 17th January next year. I hope then I can 'Semi-Retire' and work almost full time on this project, with the added advantage I will not be on such a tight budget......

But back to your point Nottus, It is one thing to read a post and agree that in principle it is possible, but completely different to sending a scale ship, followed by a mouse, followed by a recording medium and finally, hopefully, Myself.....

 

[Nottus]

However, one thing that I believe makes "Back to the Future" style time travel highly unlikely is conservation of matter and energy. For example, even though you were only born perhaps 20 or 30 years ago all of the atoms that make up you were here (basically) forever. Matter and energy are always conserved, so if the time traveler goes back in time even before his birth then we have to explain how the extra matter shows up in the universe at that time.

Science usually makes even the best sci-fi look sad by comparison. So, while we may not be able to realize physical time travel we may be able to achieve a certain influence over the past or at least over random variables in the past.

Agreed, science fiction cannot be used as a valid source for time travel because it is simplified in order for it to be understood by a general audience. Furthermore, the extra matter existing in the 'previous universe in time' can be solved due to the fact that only memory can be sent back, therefore the virtual body used to house the memory is created by nature (memory has to be contained by something, therefore nature will by default create a virtual memory given the specifications in the memory)

 

[Phil Wainwright]

I would like to think that time travel will become possible, but we then have Fermi's Paradox (yes I know I use that one a lot....) If it is possible, why have we not seen a royal visit, or presidential visit from the future?

Firstly, the reason why we don't receive a 'royal visit' is because the moment they visit us, they will be 'visiting' us on another world line, therefore we do not have a visit unless it is predestined on our world line that there will be one. Secondly, time travel isn't as simple as putting someone's ass on a vehicle and pressing the button. It involves taking a portion of a person's memory and sending it back by laser. A person would never fit in a mini-singularity.

My thoughts are along the lines of why would a person need to fit into a singularity of any size? would it not be that the singularity is used to 'steer' the future light cone to take you back? or to distort gravity to the point that spura light speed travel is possible, allowing us to escape our own future light cone?

 

[Phil Wainwright]

^^ supra light speed....

sorry, edit function not working here

 

[Nottus]

My thoughts are along the lines of why would a person need to fit into a singularity of any size? would it not be that the singularity is used to 'steer' the future light cone to take you back? or to distort gravity to the point that spura light speed travel is possible, allowing us to escape our own future light cone?

What you are talking about is time travel in science fiction. My perspective is from three years of theoretical physics. A person needs to fit into the singularity not because of how tall or how obese the person is, but because the person takes up memory, as in 5 gigabytes, 2 terabytes, 8 bits, ect. A typical singularity only fits 8 megabytes of information, which is not a lot. Therefore up to this point, we are only receiving blueprints on an infinitesimal scale.

p.s. please don't say distort gravity. Gravity can't be distorted, it is a constant force; the only thing that's distortted, if anything, is space.

 

[Ayasano]

PS, in respect to the above comment, it does suddenly fill me with hope, as the big problem (Fermi's Paradox) is suddenly resolved...... It could be discovered / invented tomorrow, and we still would not be able to come back to today.

Also, (and I have not thought about this book for years) in the book it uses a system of 'Kettles' that are almost like lift (elevator) cars that move only in time, but are physically restricted to the same place..... hmmmm, could it be that is the answer? hmmmm

Before I launch into this, I want to point out that as per Occam's Razor, your theory is simpler and probably the correct one. It does have the assumption of not being able to go back before the invention of the time machine though, so with that in mind, here's an alternate theory:

There's another way to explain Fermi's Paradox with respect to time travellers, involving the Time Traveller's Dilemma. (1) The gist of it is that the further Down you change something, the bigger the effect it has further Up, the classic Butterfly Effect. Those changes can be anything from slightly different weather to entire planets full of people never being born. If you assume that as more and more people invent time travel it eventually becomes common knowledge, you suddenly have several trillion people a few hundred thousand years Up capable of time travel who would very much like history to stay the way it was.

Note that this idea doesn't preclude things like using time travel to win the lottery. As long as you don't knowingly change an event, you can do pretty much anything you want. One person summed it up nicely in the time travel chat last night, you can go Up a week and make a note of the winning lottery numbers, but take care to gain no knowledge of who actually won. Then you go back Down and win the lottery. The actual winner when you went Up was already you, you just kept yourself in the dark. If, instead, you saw that someone else had won and decided to try and change that fact, that's when everyone from further Up comes and shuts you down.

So now you have an issue. Imagine you're the first person to invent a time machine. If time travel wasn't revealed in your subjective past, before you invented the time machine, you can't jump in your new time machine, go Down a week, or a year, or a century, and reveal it to the world. That would change history, and that's a big no no. There's nothing stopping you going Up a week and revealing it, however, but you'd be the first person to reveal time travel, so like you say, it could be invented tomorrow and then we'd all know about it.


TL;DR: There aren't a bunch of time travellers running around because history says there weren't and the first person to go back and try and change that fact will swiftly have their attempts derailed by people from further Up. Stable time loops FTW.


(1) This assumes that only a single time line exists, which is my personal belief, vs. the Many Worlds theory. That's a whole other kettle of fish.

 

[Night Templar]

Simply putt, aside from all the "print" above, it cannot be done. My opinion, right or wrong but then I still believe in the "paranormal" and the existence of "virgins".

 

[Tron1]

time travel is real and people do fake and bs a lot but it's real I have had experiences. but I haven't actually time travelled wish I could though I have to stay here I'm just a messenger. don't mind me