SciFi and Fantasy Book Club discussion

We were discussing time travel and why, if it's possible, we haven't run into anyone from the future yet.

*I* said likely there was some sort of international treaty that forbade time travel post-camera but pre-"discovery" so as not to run afoul of paradox and such.

What do you think? Have we seen our own future? Will we? What would you do to regulate it, and do you think your rules would work? Bring in any* book references you have!

*Still in Member's Chat though, so rules regarding discussion of writing still intact :)

I believe that the reason we haven't run into anyone from the future yet is most probably because some laws of physics makes time travel to the past impossible. As for time travelling to the future, I believe that is possible...one way only and slowly, by hybernating. Don't take me wrong: I love the fictional concept of time travel and time travel stories, but I think that the laws of physics are against us on this.

The physicists' consensus is that time travel into the past is impossible. Everything is moving forward.

It is possible for different objects (including people) to move forward through time at different rates - i.e., time dilation. So if some caveman had been picked up by an alien vehicle, whisked at high speed somewhere else, and then made the return trip back to arrive at Earth today, he might be still alive and only a few years older than when he left.

Many sf stories feature time dilation. Pushing Ice has its main character interacting with an object made by a later civilization. In The Left Hand of Darkness, diplomacy with Winter is so difficult that the diplomatic ship periodically leaves and then turns around to get a fresh chance with a new generation.

So many opportunities to talk about all my paranoid, delusional, conspiracy theory dreams come to life.

What about timeline *hopping* not exactly time travel- but jumping from one timeline to the next. Every moment that ever was and ever will be is always happening now (like in Arcadia). Yesterday is now. Tomorrow is now. 500 years from now, is all now. Somewhere in the next dimension/timeline- a caveman is inventing the wheel, right now.

This is also touched upon in Dark Matter. Basically every choice you make makes a new timeline (and a new you!)

In All Our Wrong Todays cosmonauts were cloaked in invisibility and somehow made immaterial so they could not interact with the past they were observing.

So if All Our Wrong Todays is correct- then how would we even know if time travel will come to be invented? Maybe in the future they are watching us and obsessing over the drama of our lives in the bestest reality TV show ever made or you know- screwing with our lives and seeing how we react like in The Sims. Maybe- people of the future are god.

I think that movie Interstellar sort of portrayed time travel this way as well, admittedly through black hole inter-dimensional travel.

So timeline hopping is the way that makes most sense to me- if time travel could ever conceivably be a thing. Thinking about the forward backward linear time traveling just makes my brain blow a gasket.

I once saw a line, something like "If time travel will ever be possible, it's already possible" because if someone traveled to the past, it would mean bringing the tech with him.

Anyway, it also reminded me of the scene in The Big Bang Theory where Sheldon and Leonard are writing the Roommate agreement. There's something like "If anyone of us invents time travel, we agree that the first travel will be to the moment 5 seconds from now." (5 seconds of silence) "Well, that's disappointing."

Back on topic, I am not sure if it would be possible and how it would behave, but the fact that someone could, even indirectly, erase his or her own existence, would probably deter most.

As for future, be it travel or just sight, I'll again voice my thoughts using a movie line. "If you show someone his future, then he has none." Knowing my own future would make my life boring beyond limits, just waiting for things to happen...

Chris wrote: "The physicists' consensus is that time travel into the past is impossible. Everything is moving forward.“

Actually, the consensus, if such exists, is that time travel is allowed by physics but is probably forever beyond our capability. The energy requirements as they stand now are beyond colossal. I don’t recall the exact number but it was something like the entire output of our sun over its 10 billion year lifespan. There was some talk a few years ago that the energy requirements were reduced by a significant amount (90% maybe) but that still leaves it in the Oh Dear That’s Quite Preposterous range.

But new breakthroughs are happening all the time and we just started really thinking about this as a species. We’ve already achieved teleportation (of photons, but still) so who knows what might happen in years to come.

Tomas wrote: "Back on topic, I am not sure if it would be possible and how it would behave, but the fact that someone could, even indirectly, erase his or her own existence, would probably deter most."

I’ve done a lot of reading about FTL and time travel — and they seem inextricably bound together, in that you get both as a package deal or not at all — and the most fascinating thing about the most likely method, which is travel via wormhole, is that causality is not a factor.

Meaning that “cause and effect” are decoupled. So the famous Grandfather Paradox, where you prevent your grandparents from meeting thus erasing you from existence thus preventing you from preventing their meeting, that whole conundrum goes away.

If you prevent your grandparents from meeting, then your parent no longer exists but you still do. THAT is as twisty a ball of knots as the Grandfather Paradox, and they’re not sure if it invokes branching timelines or alternate universes, but the math seems to bear it out.

Freaky deaky,

It's possible to hypothesize a kind of time travel that only goes forward, or has a lot more on going back. Poul Anderson's Flight to Forever -- great story -- has just such limits.

What about the scenario envisaged in the book Dark Matter, where each decision a person makes creates a new universe (according to the multiverse theory of quantum physics). Then if you tried to go back in time, which universe would you go back to? There would be a google of universes to choose from.

Forward, yes, but backward would rejoining, not severing universes.

Mary wrote: "Forward, yes, but backward would rejoining, not severing universes."

Wouldn't coming back also be a decision and a split in the universe?

If not, you would have many people from many different universes coming back to the same universe?

Scads of them! But that's not a problem with choosing.