Personaly I don’t think that parallel universes explain squat. If this is true than said person isn’t really traveling through time. He is just traveling to a parallel universe.
Of course, this would only be a paradox if the time traveller’s grandfather fathered the time traveller’s father…maybe grandma was a slut.
Travelling back in time seems relatively possible, but getting back to the future seems like it would be a PINA.
Granted Im only a casual stationary observer of these forums, but it seems like the only interpretation of the implications of quantum physics anyone ever brings up here is the many-universe theory. There are like nine different relatively main stream theories and the many universe isnt even as well received by physicists as the observer-created universe/participant hoolie-gag thingy.
I’ve been curious for a while about going back in time
and doing something that has no effect until you return to
the future.
EG I travel back in time to the 60’s. While there (or is that then?) I buy some collectibles that have great value in 2001. I buy a safe deposit box in a bank that I know survives today. I take measures to protect the items (proper packaging to protect from moisture, temperature, acid etc.). I give the bank instructions to deliver a duplicate key to my house the day after I return to 2001. I get back to the present and go to bed. The next day, the key arrives and I have access to very valuable items.
Since this doesn’t change my past, would it be paradoxical? While it has some effect on the past, the fate of a few comic books, or toys and one safe deposit box and telegram would seem to be neglible. Though “The Sound Of Thunder” and Homer Simpson’s use of a time-toaster both hold that even seemingly insignificant changes alter history to a great degree.
What about the 'A Tim Traveler Did it" question? I go back in time and see someone put out the Great Chicago Fire before it consumes even a single house. In order to make history happen as it did, I must start the fire. An episode of Quantum Leap has Sam leaping into Oswald. (SPOILER)He doesn't save JFK. But Al tells him that originally, Jackie was killed as well. History as we know it, happened because of a time traveler.Assuming time travel is possible it may be worth pointing out that everyone in the present would have absolutely no clue history had been changed if someone did go back in time and alter our history. For all you and I know Hitler and Germany won WWII up till about 2 minutes ago when some time travelers went back in time from our present to change something that allowed the allies to win (this assumes there is only one universe and not the many universes concept). Your best friend in the whole world might have disappeared 10 seconds ago due to someone meddling with the past and you’d never even know it much less actually miss him or her.
One of my favorite ST:TNG episodes of all time was called Yesterday’s Enterprise where an earlier version of the Enterprise gets sucked into the future via a rift in space. In the episode the bridge of the ‘current’ Enterprise shimmers a bit and everything subtly changes. In the new future the Federation is at war with the Klingons and losing because the ‘old’ Enterprise was never allowed to finish its life in the past and do some things that would have ultimately averted the war. Of course, everyone on the current Enterprise have no clue anything has changed except for Guinan (Whoopi Goldberg) who somehow senses something is amiss. This episode is notable for bringing Tasha Yar back since she was never put in a position to die in the new timeline the time travelling Enterprise created. In a further twist Captain Picard allows Tasha Yar to go back in time with the old Enterprise to restore the timeline to its previous state which allows Tasha Yar’s daughter (a Romulan) to give headaches to the crew of the Enterprise in a future episode. At the end of that episode the bridge shimmers again and everything returns to ‘normal’…the crew of the Enterprise have no idea what just happened and proceed merrily on their way. The kicker is when they run into Tasha Yar’s Romulan daughter in a later episode since they know that Tasha never had children much less with a Romulan.
That’s all a bit OT but it was fun remembering that episode and it illustrates some of the weirdness you might expect when messing around in time.
Just read some good SF. Hundreds of great books exploring all kinds of different ramifications of different takes on time travel.
Just read some good SF. Hundreds of great books exploring all kinds of different ramifications of different takes on time travel.
BTW, I like Larry Niven’s explanation for why there isn’t time travellers. OK, imagine at some arbitrary point time travel is invented. So one or more time travelers start going back into the past. This continues until sooner or later they do something to mess up the past enough so that time travel doesn’t get invented. A non time-travel universe is in an infinitely more stable/robust state than a time-travel universe, so we inhabit the former.
Quoth Jdeforrest:
Quite the opposite, actually. Suppose that tomorrow, I go back in time to 1951. If I want to get back “home”, all I have to do is wait 50 years. Well, then I’ll be in my seventies. So, I could develop some sort of hibernation-sleep or something. The date on my watch would still be off, but there’s ways I could take care of even that: If I just go for a 50-year space flight at high speeds, then all of my biological and psychological processes and all clocks I carry wih me will agree that it was only a short while.
It’s easy to get information from the present to the future, or from the past to the present, but there’s currently no known way to get information to go in the other direction, and therein lies the problem. A person’s got a lot of information, and if you want to be in any state remotely resembling alive at your destination, you need to keep that information with you.