Philosophize with me a minute.

I'm thinking right now. Your thoughts?

Ah, a time travel post. This brings me back to the massassi of old, where giant discussions on time travel, the universe, religion, and abortion where everywhere, and the discussion was generally civil. I had this brilliant bubble-within-a-bubble theory of the universe, which in retrospect was complete bunk.

As for time travel... I don't really think it's possible. I think time is a construct of the mind.

I completely agree. But then that raises even more questions...

No, no it's not.

Great arguement, Cyggy.

I like Einstein really don't believe the universe to be random but to be mechanical. With that said using the current characteristics and positions of every atom in the universe we can guess what happened in the past. Then using a gigantic machine reverse all the matter and energy in the universe to our guess. I really don't see any other way :/. As for going forward in time, just go really really fast or something.

If time is part of the physical world, then I suppose time travel isn't necessarily illogical.

In theory that is probably true, in practice, how do you propose you build a machine large enough to alter the universe? And how can this machine alter the universe that it is in itself a part of?

@ Tinny: Tell me, what would you build this machine out of?

If an event is just a 4-dimensional coordinate in space-time then it's just a matter of changing the 4th (time) coordinate of an event. I suspect it's not quite that easy though :p

It's impossible to predict the future with 100% accuracy, because even if you know the state of everything in the universe, the only thing that can determine the future states is the universe itself. It's impossible to run a simulation that takes into account everything at a faster speed that what it's simulating. With this in mind, imagine how difficult it would be to extrapolate backwards in time.

Too bad time isn't the fourth demension.

And also, how do you plan on changing the coordinates of an event? An elaborate COG? :p

Dunno, we could probably put it in a pocket universe and have it send rays for instructions on how to reconstruct our universe.

yes actually, I coded it just now.

I'm taking high school Vector Geometry and Discrete Mathematics and basically what I have learned so far is that you can't have unrelated vectors interact...that is to say, you can't add a speed vector to a position vector, etc....i.e. you can't have a vector component of say, time, when the other three components are positions. Etc.....:confused:

Time is just a theoretical construct that doesn't really exist. Of course, we use it all the time, for a ton of different things, but how is that different than a point, line, and plane? We use those all the time too, but they don't exist in the physical world, because they have no volume.

Sure you can. Assuming time is a dimension (the fourth even), it is a position. Human (and most, if not all, earth life) can experience the 4th dimension, but they can't move through it.

I love you.

Yeah, but, while the other three components in 3-space can be measured as distances (metres, etc.), for time to be a component it must also be measurable in, say, metres, etc.

This thread is funny.

Isn't it?

Maybe the trick is just figuring out how to convert seconds into meters.

Yes, that really would be the trick.

Step 1: x
Step 2: Become Master of the Universe.

Step 3: Profit!

Where x would be the obtaining the sword of destiny.

Oye, i made a fanfic on this here:

http://forums.massassi.net/vb/showthread.php?s=&threadid=30238

We don't know everything about the inner workings of time.

From our perspective, everything flows through time in the same direction and sense, but that's only what little we can see of the universe.

Assuming time is a function that is applied to every single thing that exists in our universe, could it be possible that different things might have different variables, and might be affected differently?

What if matter or energy of a yet unknown kind could travel in different directions, or completely backwards? Just as things exist in time, things may exist in anti-time. For instance, an anti-time explosion would constantly shrink from our perspective, but grow bigger in the past. If the explosion is created right now, from our perspective, we'd see nothing. Theoretically, if we went back in time, we would see it in it's larger state, and then it would shrink again (from our perspective). The further back in time that you go, the bigger it is. Yet whenever you look at it, you see it shrinking. Why? Because we only perceive the universe in normal time. Therefore, it would be extremely unlikely that a human being could travel back in time. However it may be possible for other things to do so. Not only might there be such a thing as anti-time matter, but possibly matter than flows through time at a speed different from our own - essentially speeding up or slowing down time from our perspective.

What the hell are you guys talking about? Time isn't a theoretical construct; the way we measure time may be, but time itself is not.

If time travel was possible, people would have come back and fixed stuff up. End o' story.

But I can dream...

Ah, but that doesn't mean the human race will ever achieve it. Maybe we all die in 10 days!

You may want to look into a book called Flatland. It takes place in a 2 dimensional world where a 3rd dimension is explained to a relatively respectable line by a cube who effectively shows it to him, and shows how difficult it is to explain an extra dimension to beings who haven't actually seen it.

Whoops, correction: the inhabitants were triangles, squares, etc. The more sides you had, the higher your standing.

time is not a demention, it's a phanamina

Time travel causes headaches.

Time is not a dimension, it's a phenomenon.

Precisely.

I postulate that time itself is merely our perception of the order in which energy interactions take place.

For your reading pleasure, a sphere attempts to explain in words the third dimension to a square living in a 2-dimensional world.

http://www.alcyone.com/max/lit/flatland/16.html

I'd bet that time travel is possible. And why not? Note that all the fundamental physical laws don't have time in them, i.e. they work the same going forwards or backwards....

Never mind, not sure where I was going with that.

As for the causality paradoxes that would be created by going back in time, those can be explained away if you accept the multi-universe theory (wherein every time a quantum particle "chooses" a state, a new universe is formed. or something like that).

As for converting seconds into meters, you just need to find a handy constant that has the units of m/s. (Hint: the speed of light is a constant with units of m/s). I also remember this explaining the theory of relativity somehow, where distances were actually the pythagorean sum of the change in the time coordinate and the change in the distance.... something like that.

Don't bother arguing with or correcting this post, because this is all pulled out of my *** and/or several physics books that I've read.

Time moves in the direction of increasing entropy, which is amount of chaos in the universe. Simple example: an explosion. Nice happy trinitrotolune stick all of a sudden gets pissy and decides to throw **** all about with great force and energy. Order -> Chaos, increasing entropy.

IIRC, from modern physics class, there is nothing in Relativity that prohibits time travel. The only thing that Relativity says about time is that as v -> c, ∆t -> 0.

I'm sure our local armchair fizicks expert's book on Timeral Physics explains it in great detail.

<3 Ric

This is how the possibility of time travel was explained to me, and assuming that the assumptions hold true then it should be possible.

Say you throw a baseball at about 40 mph. Then you get into the back of a truck, and throw a baseball forward at your 40 mph strenght, the combined forces of your throw and the speed of the truck will make the ball go about 80 mph.

Light travels at 300,000 feet per second, or some insanely high number that so far is impossible to reach. But the thing about light is it ONLY travels at 300,000 feet per second. If you get into the truck, going 40mph, and turn on a flashlight, facing it forward, the light coming out of that flashlight will go 300,000 fps... the fact that its in a moving truck has no effect on its speed.

Since speed is a measure of distance and time, S = D/T, and the speed of light never changes (this is what the TV program taught me... light never changes speed) then that means TIME had to change to compensate for the light.

Since we are talking 40 mph or so here, the adjustment time would have to make for the light is insignificant. But it did have to change if light never changes speed, which means time had to speed up a little tiny bit to compensate for the light, so that it only traveled 300,000 feet in one second.

If we were to build some kind of super spacecraft (because we probably dont have enough distance in this planet to make a craft that isnt supported outside the atmosphere), and this spacecraft could faster than the speed of light, say 330,000 fps. The craft would get going, turn on a light, and since the light cannot exceed 300,000 fps, time has to speed wayyy up. So as far as the guy in the craft can tell, 1 second has gone by after 300,000 feet. But for the light to maintiain its 300,000 fps, 2.1 seconds have to have actually gone by for everyone else. You keep adding all this up, and the guy stays in the craft for a day, 2.1 days have gone by on Earth. Keep it going somehow for 5 years, the guy has aged 5 years while everyone else aged 11 years on Earth, and he's technically traveled 6 years into the future.

Going backward in time is something I do not think we can do. However, sitting here thinking, I found a way the guy in the craft could just age faster than everyone else.

If the craft was going 150,000 fps, half the speed of light, and turned on a light facing backward from his craft, then the light would need an extra second to go by for the guy while making it so only one second went by for the rest of the world. If that kept up, the guy would be in his craft for 10 years, and age 10 years, while the rest of the world only aged 5 years.

If the craft were to be going faster than light, say 330,000 fps, and turned the backward light on, what should happen is after 1 second the light ends up 30,000 feet forward from the point where it was activated. This is like if you threw the ball from the truck backward at your 40 mph strentgh and the truck was going 60, the ball would go 20 mph in the same direction as the truck. Technically, if you did the same thing with the light and the craft going faster, the light would never even go past the point of where it was turned on. So someone who was behind the craft when it turned on the light would never see the light being turned on because the light is not going their direction. If for some reason it does, its just too mind boggling for me to figure out what time had to do to get the light to a point where it never actually existed....

I spent about an hour just sitting here thinking of how to go backwards in time with this method and came up with zilch, I could only think of how to go forward...

Well with that method I'm sure you'd have a great time in the future...in a big black void lightyears away from Earth.

I believe if time travel is possible, it is only in a limited sense. Going back/forward to different time periods is just a dream. It's impossible. Going back in time yourself isn't going to turn everything else back in time too. You would just be in the past, everything else would be in the present...

then the Universe would crash and God would have to reboot!

So don't do it.