Ok, if time travel were possible, now or in the future, wouldn’t we know it? Wouldn’t we have known it since the beginning of humans?
Why I say that is, if it is ever going to be possible, wouldn’t someone from the future have contacted us by now? Even if it take a million years before it’s physically possible and figured out, couldn’t they just come to our timeline and let us know how to do it?
Isn’t the fact that we have never had a traveler contact us from the future proof that it’s never going to be possible?
Now don’t get all worked up, I know how all you time travel people are, I’m just thinking about this.
I feel sure I’ve posted this before, but there is a way around Fermi’s paradox. Imagine a kind of time travel that makes it necessary to create a gateway - for example, I could create a gateway right now, for March 4th 2001 6:57pm. Any time in the future, I can create another gateway (portal, wormhole, whatever) and travel to other gateways that I’ve created in the past. Obviously this means you can’t travel to a point in time that has no gateway. If this kind of time travel is possible, that means you’d never be able to travel back into the past prior to when this technology was created. The first gateway would be the farthest back you’d ever be able to go.
Time travel is rare for much the same reason space travel is rare: because it’s a royal pain in the ass. Most methods of time travel require exotic matter and/or intense gravitational fields, and tend to be both hellaciously dangerous and prohibitively expensive. Sure, you might think it’d be keen to have a firsthand view of Bronze Age China or the battle of Gettysburg or whatever, but after you calculate how many of Jupiter’s moons would have to be compacted into liquid neutronium to fuel your trip, the whole thing starts to seem more trouble than it’s worth.
Plus, even with the more moderately priced forms of time travel, there’s the not-inconsequential drawback that you can’t ever return to your own time. Travel into the past necessarily alters the timeline, so that the original course of events that led to your departure in the first place will never occur in the new timeline. Your arrival point in the past becomes the branch point of a parallel universe.
Even if you only travel back in time five minutes, you appear to vanish permanently from your original timeline, while from your perspective you arrive in a past that already has another you in it. So you’ll both probably have to fight to the death. That’s usually how these things work.
Maybe we don’t have the technology and haven’t been able to “tune in” to the “broadcast channel”. Perhaps, time travel is possible, but not in a conventional or classical literary sense and is entirely impractical or impossible for physical beings-- maybe the only thing that is possible in the realm of time travel is a transmission to the future and/or past of information at a quantum level. Would we have the ability at this point in mankind’s technological development to receive that transmission?
What we need is the SETI equivalent for quantum transmissions. We need to listen for the future in quantum structure. There might be a ticker tape of our future just waiting to be received and decoded. The interesting thing is that as soon as a quantum channel and standard is decided for interzeit transmission then we might immediately find information from the future on our timecaster.
And let’s not forget Heinlein’s wonderful All You Zombies …. I’m pretty sure that’s the title. It’s in the collection The Unpleasant Profession of Jonathan Hoag.
Time travel wouldn’t necessarly be desovered, just because it’s possible. The time travel mechanism could always be fatal or mostly fatal for matter, so it just doesn’t get used. Everything is in motion, so the unless they can cause spacial movement at the same time, they will be in a void or less friendly spot. To calculate where the relevant portions of the universe are at, might never be in our abitity to computate.
Suicide by paradox. If they told us how, our descendants wouldn’t go on to invent time travel in the future, and then they’d never go back in time to tell us what to do, & etc. With that said, our present day will probably be pretty interesting from an academic standpoint of the future. If time travel will/can be invented, I’m guessing they’re already here.
Time travel is not only possible, it’s quite easy, the problems arise when the time traveller realizes that travel backwards or forwards in time means that the earth is not in the same space as it once was. he realizes this, unfortunately, as his lungs explode in outer space.
