Here we go, the discussion you've all been waiting for (or would be waiting for in the future

Time travel.

If time were linear then time travel would be as simple as getting ona bus and traveling to your destination with a return ticket securely in your back pocket.

If time weren't linear then the first step on your journey would be the point of no return as you going back to a time (say a year before you were born) would change the past (as you were now where you weren't before) and therefore the future would have changed from this point on.


...or would it?

OK Class, you seem to be ignoring this assignment so try this instead

Time travel is impossible...Discuss

I've written about time travel dynamics before.. a few of the stories I've written deal with time travel.. predominantly I've viewed it as non-linear.. though not a point of no return. Unless you changed things on a massive scale and I do mean massive, the world you return to would be relatively unchanged.. except for some details of your life and those lives that you directly have impacted, in both the past that you traveled too.. and over the lengths of time and occasions that you had known or otherwise effected them... etc etc. blah blah blah. *rambles on some more and shuts up*

But do you not think that a time traveller arriving from the future would change things on a massive scale?

Or do you think the traveller will still be part of his own continium and be just an observer in the one he is visiting?

Time travel alters reality. It's not time you step back in in your example. In your example, all memory of your previous time, all cellular decay and events that happened in the time you are travelling back, would need to be nullified. In your example, you step back in time, and into another reality.

..so it's not time travel.

The only way time travel would be possible would be to go back to a time when the history books said you did.

If time travel will ever be possible shouldn't history tell us about a time when someone appeared from the future?

maybe... it could be that history does...Imagine a man with holographic technology... anti-gravity equipment... called Merlin?

Perhaps it would, perhaps it wouldn't.. but if he did nothing to alter the course of history.. how would it change things on a massive scale?.. woo.. theoretics are funnnnnnn

Another possibility, when you travel back in time you do change the future of the universe. Not the future you came from but a new alternate path in the multiverse. just a thought

one does not know what may or may not alter history on a grand scale it only takes a second to set things into motion

who is to say time travel hasn't happened before, or that the history we know it isn't altered in some way already

why would the traveler's memories not be altered if his travel alters reality

what if to travel back you become yourself at the time you travel back to (deja vu) so that only the subconscious knows it's purpose.... now why did I do that? ... I have an overwhelming urge to...

hmmmm ~wanders off to reign in all the thoughts swirling round~

nice topic!

I would think it is impossible. It may be theoretically possible to send a signal back in time, but in order to fold time and space back upon itself, to bring two events together, you would have to focus enough energy into a point in spacetime to vapourise anything in the immediate vicinity. In order to create a spacetime portal of this type large enough for a man to pass through, you are talking about quantities of energy which would tear planets apart...

Even in the highly improbable event that one could master the technical hurdles, using a bridge like this to cross space and time would be impossible, because it would be unsurvivable...

Mmh, scientists believed nuclear fission could not be controlled. Now they're experimenting with nuclear fusion... It'd not surprise me if they will construct an (offplanet) M/AM reactor within this century. That one would be capable of the energy demands you set... Apart from that, natural wormholes do the same already: Folding space, time and reality. Problem is, the effect in those is rather random...

It's worth noting that no natural wormhole has ever been proven to exist on the macroscopic level...

Black holes can certainly fold spacetime over on itself but nothing material can enter a maelstrom like that and maintain any kind of physical integrity.

In order to fold space and time you would need to be able to transmute mass and energy on Black Hole scales, which would mean that the area of space and time you are working on would implode, taking anything in the vicinity along with it...

Actually it wouldn't. It would be lacking by a factor of about 10 to the 12th...

The barriers against fission were technical, as are the barriers against fusion now, but I believe that the barriers against traversing an artifical bridge between two events separated by spacetime metric are theoretical...

I would urge you to get a copy of "Hyperspace" by Michio Kaku. It's an absolutely fantastic book, and explains hyperspace right from the invention of the metric tensor and the charlatans who exploited it in the 19th century through to superstrings and M-Theory.

It's all done in a way that someone like me who is not a mathematician can still understand...

Not quite. M/AM (matter/anti-matter) reactors deliver pure energy. And their size... well, is scalable.
Those barriers you speak of can be broken. If raw matter can get trough, so can energy. If energy can go trough, so can data streams (information). And matter can be converted to energy and information... Theoretically. Sorta like the star trek transporter

Perhaps I will. I have a hunch however, it won't change my mind...
Here you fail. Gravity creates a maelstrom perhaps... But will suck anything with it's flow. Therefor, material integrity is NOT compromised. Matter may be compressed a bit more under intense gravity, but will stay itself. If you throw a log into a wild current, it doesn't splinter in the water either... (unless it hits a big rock or such).

You're forgetting one salient point. You need the energy to create the antimatter in the first place, then you need to use massive amounts of energy to isolate the antimatter (space is by no means a vacuum)




Totally different premise. And besides if I was broken down into a datastream, and an identical copy made of me at the other end, it does not alter tha fact that I will be dead and a copy will have taken my place.




If you understand it, don't doubt it for a second. It will revolutionise the way you think about space and time. Some of it will be highly disturbing and difficult to accept, but it is without doubt, the closest thing to visualising spacetime that beings compelled to sensory input from 3 space can really have.

Quote:

Here you fail. Gravity creates a maelstrom perhaps... But will suck anything with it's flow. Therefor, material integrity is NOT compromised. Matter may be compressed a bit more under intense gravity, but will stay itself. If you throw a log into a wild current, it doesn't splinter in the water either... (unless it hits a big rock or such).

Not so. As one passes the event horizon of a black hole, one's mass effectively becomes infinite. No impact zone is necessary. Tidal forces alone will rip any material object to pure energy. The stretching of time and space around the so called "ergo sphere" where an object, or even a light beam's future becomes assured has been well documented.

http://casa.colorado.edu/~ajsh/schw.shtml

Check this link out...

Actually, the near vacuum would be cleansed by the antimatter under the release of some energy. Dissipate or use that energy and the vacuum suffices.
Besides, if a wormhole can be created naturally then the energy is there in abundance. Just need to find a way to harness it...
Mmh, really? Even when every memory and your emotional state are transferred with you?
Ah, words like this make it seem like a bible. And I mean that in a bad sense: A book to follow blindly without further analysis, or thought. "Revolutionise"... *chuckles* Ye're sounding like one of them tell-sell commercials
Really now? Has one ever seen that happen? Then the fields of influence of black holes are infinite... Gravity is something that stretches out into infinity. Basically, every black hole pulls at the entire universe. Just like every star, and every atom. The effect would increase gradually as you approach the core of the black hole (which is an immensely dense star) and as you pass the core (hopefully missing it) you would be slingshotted out of the black hole, provided you kept accellerating. Note that this would only apply to a frontal approach. A strafe would pull you into orbit... and prolly never release you, since light speed would not be sufficient to escape.Checked it out. Looks good. Lacks the info to adress the topic here: Free fall orbits are not what is needed to gain a timetravel effect. Slingshotting around a black hole can do that as well. And from your own perspective you would face the normal accelleration G's your craft provides...

I have never understood why people have this romantic notion of anitmatter as an energy source. Vis a vis the laws of thermodynamics, it is impossible to get more energy out than the energy you have used to create the antimater. In fact, with your machinery being less than 100% efficient it will be rather less. Or going to harvest it are we? Incase you hadn't noticed, anti matter does not exist in this region of space and time, and to create even a single particle of it requires massive amounts of energy and millions of dollars. To then contain it for more than a fraction of a second is impossible...

Quote:

Mmh, really? Even when every memory and your emotional state are transferred with you?

If I had a clone made of myself with my memories and emotions then I blow my head off with a revolver, do I still exist? Hardly. The same applies if my molecules were broken down to energy and a copy made at the other end of a databus. Outside observers may not notice any difference, but I would still be dead. That's what happens when you disintegrate someone. They die.

Actually, I thought my assertion was that space and time are beyond our ability to understand. We can simply make rules of thumb like quantum theory to help us build tools and answer questions. It's worth noting that no human who has ever lived has managed to visualise the spacetime metric of 4 dimensions, let alone eleven. We can try to imagine how a tesseract would fold into a hypercube, but all we can see are shadows of fourspace...

Quote:

Really now? Has one ever seen that happen? Then the fields of influence of black holes are infinite... Gravity is something that stretches out into infinity. Basically, every black hole pulls at the entire universe. Just like every star, and every atom. The effect would increase gradually as you approach the core of the black hole (which is an immensely dense star) and as you pass the core (hopefully missing it) you would be slingshotted out of the black hole, provided you kept accellerating. Note that this would only apply to a frontal approach. A strafe would pull you into orbit... and prolly never release you, since light speed would not be sufficient to escape. Checked it out. Looks good. Lacks the info to adress the topic here: Free fall orbits are not what is needed to gain a timetravel effect. Slingshotting around a black hole can do that as well. And from your own perspective you would face the normal accelleration G's your craft provides...

Sling shotting around a black hole is not going to achieve time travel. It might stretch you into a strand of spaggetti, and it might add a few birthdays onto your colleagues on Earth because of the dilation of time, but that's about the best you can hope for.