h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Parrallel universes etc.
If using the time travel=parrallel universes theroy, take a couple of things in mind, if person A were to go from 2002 to 1967 (new universe created by the possibility of you doing it) any action you take in this new universe(universe X 1967) would not effect universe Y(2002)but, the possibility of getting back correctly to the right universe(i.e here) without a stable "wormhole" is quite frankly, impossible(or infinitely hard, depending on your view)
Any action taken in universe Y wouldnt effect the outcome of X, simply because it has no corrosponence to each other.
The universes would evolve on roughly the same way, depending on your actions in Y (say, killing bill gates) things would the same.
As for wormholes and 4th + dimesional space, ever considered the possibility that there is no time, or space, but this is simply the way humans comprehend the "universe", and that physics as we know it, is just an amusing joke to people more highly evolved than us?

About parallel universes: I agree that, in a quantum multiverse, time travel is possible. When you go back it time, you would in fact be creating a new universe. Whatever you did in this new universe would not matter to your old universe, because there would be no direct connection. Of course, it would likely be impossible to return to the present of your original universe, but such is the punishment for attempting to disturb history.

As for your second comment...No, I've never envisioned the universe that way. I guess that's because I'm not on drugs . Serously, though, that's a possibility, but I'm going to use Occum's Razor and say that the simplest conclusion (that the reality we see is the real reality) must be true.

PhysicsMan

:P well someone actually understood what i wrote... sometimes i have a little trouble transfering ideas from thought to paper...
Interesting thought about the "punishment" but unless you are stating the universe is self-aware, or has a set of rules to make such a punishment work, i don't think it would happen quite that way.
What i think may happen instead of the whole "punishment* is unless you have a stable , lets say "wormhole" from your destination to your arrival point, you would be hard pressed to find your way back to your original universe. Especially considering with the "parrallel universe theroy" that universe would continually split again and again, going by the choices people make even forces of nature, and animals would have an effect on the universe, even the smallest of actions would create a pair (or more) of new universes, making travel back to the original universe, impossible.
Within 5 minutes of leaving your universe, billions upon billions of new universes would be created. Making a return, well pretty damn hard.
As for the last comment, you gave, in an infinate universe, all possibilities are true. Hell in place there may not even be physics as we know it. All "laws" may very well be mutable, and our "adavanced science" may still very well be a galactic joke...

Chucky

There are several books that relate to these subjects that you may wish to read. Regarding time travel and alternate universes, one called "The Green Futures of Tycho" may be of interest, although I cannot recall who it was written by.
As for the possibility that our science is simply a joke to those more advanced than us, you may wish to read the Uplift Saga by David Brin.

I don't really agree with your remarks about the "punishment." I feel that, assuming we're in a quantum multiverse, then when you go back in time using your wormhole or whatever, you get sent to some random universe. Then, when you go back to the present, you are again sent to a random universe. I don't think you could possibly return to your own. As far as your suggestion, even if "your" universe had split into millions, you wouldn't really care; all you would want would be to return to one of those millions. However, I feel that this would not be possible.

PhysicsMan

Ok, so time travel in the Schroedinger infinite alternate universes model can be summed up (albeit roughly and rather simplified) as such:

You are in your time machine at your lab in Universe A. You travel backwards in time to what you assume is the past. The past you travel to will be the past of Universe A, however, the second you begin the travelling sequence, a Universe is created where you DIDN'T travel back in time, but instead decided to get a ham and cheese sandwich and forego this time travel business. We will call that Universe A2 for the sake of argument. Follow me so far?

This is of course much simplified, as in theoretical reality an infinite number of universes would be created the second you travel back in time, their point of divergence all occurring at the moment you travelled backwards.

Anyway ...

Let's say, once you're there, you somehow change history. Nothing too sweeping, like reversing the outcome of Waterloo or murdering Adolf Hitler in 1921, but something local, like stopping an old lady from being hit by a car. The second this happens, Universe A (where you have gone back in time to) sprouts a tangent. This tangent is now the timeline you are following. We will call this TanUniverse A. What happened to Universe A? It doesn't exist anymore. At least it doesn't for you. For everyone still in Universe A it does exist, but since you are now on a Tangent Universal Timeline, you no longer impact events in Universe A, therefore it no longer exists relative to you. There is more to this but we'll get into it at the end.

Now here's where things get messy. TanUniverse A (assuming this is an Infinite Parallel Universe model) is not simply one single timeline. You now exist in an infinite number of NEW timelines that are part of this TanUniverse. There is the TanUniverse where the old lady is a wealthy heiress and she gives you buckets of cash for saving her. There is the TanUniverse where the driver of the car is a wealthy mansion owner and he gives you buckets of money. There is also a possible TanUniverse where the old lady is a hideous brain-eating space slug masquerading as an old lady. That's the problem with Infinite Probablity. What will really mess with your head is the thought that even if she IS a killer alien from the planet Fromundula, you will only be eaten by her in some of the universes where this is true.

Well, regardless of what the old lady is, and which reality in TanUniverseA you have slipped into, if you try to travel into the future from here, you will end up in the future of the TanUniverse reality from which you left. So, if you saved the Fromundulan space beastie from the wealthy driver, and then jumped into your time machine, the future you emerge into would be one in which a Fromundulan space beastie was saved from being hit by a wealthy driver. If you saved the rich old lady, the future you emerge into will NOT be one where she is a Fromundulan space beastie. Get me so far? Oh yeah, check this out...all those "if"'s are actually happening. Regardless of whether you know it or not.

Now, as if your brain ain't cooked enough yet, trying to get home to the moment you left Universe A (you remember Universe A don't you?) is highly improbable. It is NOT, however, imPOSSIBLE. You can do it by getting back into your time machine once you are in TanUniverse A and going back to a point BEFORE TanUniverse A was created. You then sit in your Time Machine and touch NOTHING until the you arrive to create TanUniverse A. At this moment, you somehow stop yourself from saving the old lady and changing history. Now I know some of you are going to say "But Squange, if you stop yourself from doing that, TanUniverse A won't be created and then you cant go back to stop yourself, and then you get a grandfather paradox..." This is not the case, simply because, the moment you stop yourself, guess what was created...that's right, a whole bunch of new TanUniverse Realities, INCLUDING one where you actually DO save the old lady and now you're back to TanUniverse A.

So, now you're standing there holding onto yourself, and you tell yourself to get back in the machine and stop trying to change history. Let's say, once again for the sake of argument, that you listen (of course there are new Universes created in which you don't listen, but I'm sure you've already figured that by now) and you DO get back in your Time Machine and set the WayBack dial to the moment all of this silliness started. Assuming that no one saw your time machine, and you've left no evidence of your ever having been there, when the machine stops, you will be right back where you started, in good old Universe A. This trip will theoretically be instantaneous unless you decide to come back in the future, in which case you are not only going to be missing from Universe A from the time you departed to the time you arrive, but you are also potentially opening up a whole new ball of Universes.

Now, remember how I said Universe A doesn't exist to you if you leave it and go to a tangent? well, now that problem has been solved. You see, even if you DON'T decide to go back to the start of TanUniverse A and stop yourself from saving the old lady, one of the TanUniverse A yous will. So you WILL appear instantaneously back where you started from, and any outside observers will probably make fun of you since all they will see is your machine lighting up and shaking a bit, and then powering down.

Needless to say, time travel in a Schroedinger model Infinite Possibility Multiverse would be dangerous on one hand, but at the same time it would be completely safe.

time travel may be dangerous, but it's no more dangerous than anything you're doing now, since we're constantly moving forward through time and creating more bundles of infinite universes.

This si damn good! I actually get it!

Another couple of Books that will blow your mind about time are the books Manifold Time and Manifold Space by Stephen Baxter. These are really mind boggling explantions of how time and space can work. I hope that you enjoy them.

ok i dont know if this has already been posted or not, but the definition of a parallel universe is a another universe where something is difernt, theres nothing parallel about it if its the same, so in one universe i shouted f*** in the middle of a busy street but this one i didnt, think of everything you could do, in all these other parallel universes, they have happened or r going to happen, go into my space, i wrote a thing about parallel universes in my journal

Extrapolating on on squange's theory, every action and decision you make will create a new tan universe, on for if you did this, and on for if you did that. A version of yourself would exist in each one, but you would only be able to experience one of them, depending on what you did. If you were to create a time machine you could go back to when you made a certain decision to find out what would happen if you did the opposite. However, if you did this you could, in all probability, lose knowledge of the other decision, so you would go back to see what that would be like. This would therefore create a paradox.

Parellel Universes? Tan Multiverses? Where the heck is all this matter coming from? Ever hear of Occam's Razor?

Speaking of which, science has offered us an amazing opportunity with the determination that we live in a constantly expanding, never to be contracted universe (if you are to believe physics at all).

I love science and physics, and was never too sure about the god concept, but I'm now convinced that either science is bent way out of shape, or they have proven the existence of a creative force. My thoughts go like this:

Assuming the "Big Bang" started it all, we now have two choices. Either:
a) the universe was stable for all of pre-expansion eternity and something caused it suddenly to lose that stability (impossible as anything that happend in that moment should have as easily happened or been happening at any or ever moment before or after; that's what stable means),
or,
b) the pre-universe universe didn't exist for eternity and someone put it there to "Bang".
Amazingly, Science has proven the existence of God through nothing more than the combination of a given starting point, no endpoint, and logic.

To marginally expand a): Nothing that has been stable forever can become suddenly unstable, as it is always and has always been the same; the word stable means that it does not change. There is nothing that can be introduced to cause the instability, because if it were there and capable, it would have been doing it constantly.

To an eternal pre-universe universe time is irrelevant, as each kabillion years would look like every other kabillion years.
The one exception is an external force (ie: not of the pre-universe universe; ie: something capable of affecting it drastically, and arbitrarily time-wise; ie: God)

To marginally expand b): If the pre-universe universe was not eternal, than there was a pre-"bang" beginning. As there is no mechanism that we can fathom that could call a previously non-existing universe into existence out of nothing, and arbitrarily time-wise, except the act of Creation. If one defines God as a creator being, than that is what has happened.

I realize that DNA had man logicking God out of existence, but I'm afraid that Science has logicked him in. FWIW (For What It's Worth)

"Assuming the "Big Bang" started it all, we now have two choices. Either:
a) the universe was stable for all of pre-expansion eternity and something caused it suddenly to lose that stability (impossible as anything that happend in that moment should have as easily happened or been happening at any or ever moment before or after; that's what stable means),
or,
b) the pre-universe universe didn't exist for eternity and someone put it there to "Bang".
Amazingly, Science has proven the existence of God through nothing more than the combination of a given starting point, no endpoint, and logic."

What about
C) There was no time before the big bang--time started with it. The universe exists in a multiverse or a nothingness without a time dimention. All universes and all points in time within them exists simulatniously within this. Every point in time in our universe corosponds to a point in space in the outer nothingness or multiverse. This makes choosing (A) or (B) unecesary.

"To marginally expand a): Nothing that has been stable forever can become suddenly unstable, as it is always and has always been the same; the word stable means that it does not change. There is nothing that can be introduced to cause the instability, because if it were there and capable, it would have been doing it constantly."

Well, that flies in the face of your God hypothesis. If there was an eternity before the big bang, and the big bang was caused by a God, then, by your logic, God must have been creating universes constantly for eternity. If so, then a God is not needed to explain the expantion, instabilities happen ocasionally and locally. We are neither the first nor last universe to "bang".

If I may respond to the second observation first, my point was that a God/Creator Being cannot be a "part of" the universe, if He/She/It/They created it, although the universe may be part of He/She/It/Them. They would be an outside force, not a naturally occuring, un-god force within the universe.

The line 'nothing that can be introduced to cause the instability' should probably have read 'nothing naturally occuring within it can cause the instability' to make its meaning clearer.

I'm afraid, though, that the supposition that 'God must have been creating universes constantly for eternity' is a false assumption, and does not logically derive from my statement. A 'god' would create as it wants to create. There would be no reason to suppose that it has to be just once, or has to be continuously creative.

Firstly; there may be no time outside our universe. It may simply been a linearity supplied to give order and direction to the creation.

Secondly; if we are to assume that we have free will, as this conversation will attest, then we cannot deny a creator god that same freedom. All aspects of a god would not necessarilly be applied to his universe, but all aspects within it must be in its frame of reference. A God cannot create that which it does not know, even if that means it is omniscient.

As regards:
'C) There was no time before the big bang--time started with it. The universe exists in a multiverse or a nothingness without a time dimention. All universes and all points in time within them exists simulatniously within this. Every point in time in our universe corosponds to a point in space in the outer nothingness or multiverse. This makes choosing (A) or (B) unecesary.'

I believe that time starts with the beginning of the universe; that was B). But, the 'all points within them exists simultaneously would mean that it is a stable, static universe, which would be A); same thing; same two choices.

If C) is an alternative (and, mind you, one that flies in the face of the physics of the universe as we understand them [I'm talking about measurable, not theoretical physics, here]), it is one in which decisions cannot be made, as all exist simultaneously 'without a time dimension(?)'. We would be mere consciousnesses (or, maybe there is just me?) traveling through the myriad of instances, perceiving my random passage from one to the next as a function of time rather than direction.

Food for thought is all. Thanks for keeping it interesting. And, keep up the free will thing.

have a look at http://www.thekeyboard.org.uk/index.htm read through the ones you want, espially about the big bang, where did the universe come from and what evidence is there for god

After a mere brief look, it appears to be a promising thought-starter of a site. Everything we choose to believe comes to us through our senses, and amount to nothing more than our brain's interpretation of those sensory impulses. It has been accurately said that we live 100% of our lives above the shoulders and between the ears (that is still assuming that we actually have shoulders and ears, of course).

With this in mind, there can be no 'real' proof of anything outside our own consciousness. But, for reasons of survival, we are forced to reckon with the 'real' world. This means regularly trusting that doors will open, food will sustain us, we have someplace to go on a Friday night, etc.

Theories are great. I understand their limitations. But evidence takes a theoretical thought to a higher level. As a 'for instance' the expanding universe, run backwards, would seem to come from a common beginning. And, so, the Big Bang was postulated. The scientists gave some thought as to what evidence that this happened might still exist and hit upon a specific background radiation. Before they could even figure out how to look for it, scientists down the road, working on an entirely different problem (eliminating a disturbing hum coming from their new-fangled telescope, no matter which way they pointed it), had found the very vestigal evidence proposed.

This is how science sometimes works. The evidence, though not absoulutely conclusive, showed that their theory was at least not discredited.

We work from these kinds of proofs in putting to together the models that work, and separating them from those that do not. Belief is a personal thing which is why I often begin my propositions with 'assuming that ...' Without some basic, generally agreed upon assumptions, we just don't get very far.

Based on my 'assumptions', I feel that my 'conclusion' is incontrovertible. Change the assumptions, and you change it all. With 'best available evidence', I don't see any option but A) or B); but, that's just my opinion.

Thanks for the site link. I will be visiting.