Multi-universes/ Time Travel?

[apepi]

Time travel exist! I am traveling 1 second per second!^.^

[cubby]

Historically, humans have never broken the laws of physics. The only way we're traveling to the past or between universes is if you brake the laws of physics.

I love your writing and explanations - it always make me think twice. [not being sarcastic, in case it seems that way]

While we typically do not break the laws of physics, historically, the rules as we know them tend to change. Recall, the sun used to revolve around the earth.

I will offer, however, as your potential counter-argument to my statement, that physics is a relatively new science, and saying "we used to think the sun revolved around the earth" is not a solid argument, because it wasn't really a "physics" argument.

And, as answer to this (and yes, I realize I am answering my our counter-argument, but bare with me), I propose that because physics as a science is relatively new, and we may discover that rules we felt were unbreakable, might have exceptions or addendum, yet to be found.

[Wikiy]

I love your writing and explanations - it always make me think twice. [not being sarcastic, in case it seems that way]

While we typically do not break the laws of physics, historically, the rules as we know them tend to change. Recall, the sun used to revolve around the earth.

I will offer, however, as your potential counter-argument to my statement, that physics is a relatively new science, and saying "we used to think the sun revolved around the earth" is not a solid argument, because it wasn't really a "physics" argument.

And, as answer to this (and yes, I realize I am answering my our counter-argument, but bare with me), I propose that because physics as a science is relatively new, and we may discover that rules we felt were unbreakable, might have exceptions or addendum, yet to be found.

Well, i'm not really trying to say definitively that we wont travel to the past or that we wont travel between universes. It's just that physics works. Its systems, its mathematics, everything about it works. Our lives would be very different if it didn't. Some modern systems, like the GPS, are based on things that simply wouldn't work if the mathematical laws that govern them don't say what they say. And among other things, they say we wont be traveling to the past or to other universes (the latter, though, is useless to debate since we know literally nothing about other universes, or whether they exist).

So yeah, i just take the view that i wouldn't be able to have this computer if physics didn't work the way it works. And the way it works requires physicists to reject the notion of backwards time travel. It's just our technology telling me we wont travel to the past.

This is all, of course, purely in a physical context. The logical implications of time travel to the past are sort of unthinkable.

[cubby]

Well, i'm not really trying to say definitively that we wont travel to the past or that we wont travel between universes. It's just that physics works. Its systems, its mathematics, everything about it works. Our lives would be very different if it didn't. Some modern systems, like the GPS, are based on things that simply wouldn't work if the mathematical laws that govern them don't say what they say. And among other things, they say we wont be traveling to the past or to other universes (the latter, though, is useless to debate since we know literally nothing about other universes, or whether they exist).

So yeah, i just take the view that i wouldn't be able to have this computer if physics didn't work the way it works. And the way it works requires physicists to reject the notion of backwards time travel. It's just our technology telling me we wont travel to the past.

This is all, of course, purely in a physical context. The logical implications of time travel to the past are sort of unthinkable.

Ah, ok - so what you're saying, if I'm understanding this at all, is that the physical universe has certain laws, and those laws can't be broken? What does that mean? Have you ever heard of the phrase "rules were made to be broken"? I mean, come on! Isn't gravity just a "theory", like evolution? Can't all those "theories" be proved wrong at some point?










Just kidding - gotcha!

So you're saying that the same laws of physics that our working computers are based on, also say that time travel backwards is nearly, if not entirely, impossible? Am I understanding that correctly?

Would you mind elaborating on why time travel to the past is impossible, but future isn't? Just for my knowledge - I'm honestly curious.

---------- Post added 2012-10-13 at 09:55 PM ----------

Well, i'm not really trying to say definitively that we wont travel to the past or that we wont travel between universes. It's just that physics works. Its systems, its mathematics, everything about it works. Our lives would be very different if it didn't. Some modern systems, like the GPS, are based on things that simply wouldn't work if the mathematical laws that govern them don't say what they say. And among other things, they say we wont be traveling to the past or to other universes (the latter, though, is useless to debate since we know literally nothing about other universes, or whether they exist).

So yeah, i just take the view that i wouldn't be able to have this computer if physics didn't work the way it works. And the way it works requires physicists to reject the notion of backwards time travel. It's just our technology telling me we wont travel to the past.

This is all, of course, purely in a physical context. The logical implications of time travel to the past are sort of unthinkable.

Ah, ok - so what you're saying, if I'm understanding this at all, is that the physical universe has certain laws, and those laws can't be broken? What does that mean? Have you ever heard of the phrase "rules were made to be broken"? I mean, come on! Isn't gravity just a "theory", like evolution? Can't all those "theories" be proved wrong at some point?










Just kidding - gotcha!

So you're saying that the same laws of physics that our working computers are based on, also say that time travel backwards is nearly, if not entirely, impossible? Am I understanding that correctly? So if those physical laws weren't solid, our computers wouldn't work the way they do (among other things), but because they do, we can't travel back in time.

Would you mind elaborating on why time travel to the past is impossible, but future isn't? Just for my knowledge - I'm honestly curious.

[apepi]

Well, i'm not really trying to say definitively that we wont travel to the past or that we wont travel between universes. It's just that physics works. Its systems, its mathematics, everything about it works. Our lives would be very different if it didn't. Some modern systems, like the GPS, are based on things that simply wouldn't work if the mathematical laws that govern them don't say what they say. And among other things, they say we wont be traveling to the past or to other universes (the latter, though, is useless to debate since we know literally nothing about other universes, or whether they exist).

So yeah, i just take the view that i wouldn't be able to have this computer if physics didn't work the way it works. And the way it works requires physicists to reject the notion of backwards time travel. It's just our technology telling me we wont travel to the past.

This is all, of course, purely in a physical context. The logical implications of time travel to the past are sort of unthinkable.

I get what you are saying but they could be built upon? I think The only guaranteed thing is that there are no guarantees and not even that is guaranteed.

But yes, some of our implications are correct. But we know nothing about time travel, so how can you say something is wrong when no one really has tried to do it?

[Deleted]

Three words:

El Psy Congroo.

[Wikiy]

So you're saying that the same laws of physics that our working computers are based on, also say that time travel backwards is nearly, if not entirely, impossible? Am I understanding that correctly?

Well, not really computers, i was just extending the reach of the laws to include all of physics, and if the hardware is about anything, it's about physics. You could take another example, though. GPS would display your location wrongly, by a few dozen km, if the software didn't take into account the fact that time passes slower in orbit, where the satellites are, compared to where the information is being sent, due to 2 things: the satellite's speed relative to where it's being sent (30 000 km/h) and the fact it's farther from a gravitational source, which causes the spacetime around the satellite itself to be curved less, which in turn, along with the speed of travel, makes time pass slower compared to the surface of the Earth.

The theory that explains all of this is general relativity.

Would you mind elaborating on why time travel to the past is impossible, but future isn't? Just for my knowledge - I'm honestly curious.

Well, first i should make this clear: What we in this thread and physicists or people in generally refer to when they say "time travel is possible" is actually not really time travel. It's just traveling faster in relation with the rest of the universe, or a specific place, like Earth, at speeds close to the speed of light. At these speeds, anyone in a hypothetical ship would feel time passing normally. Every single thing on the ship would be perfectly normal. Except, once it starts traveling at normal speeds again, the hypothetical person would find that "more" time has elapsed in the rest of the universe in comparison to the ship. The closer you get to 300 000 km/h, the faster time will pass for the rest of the universe in comparison to you, and therefor, the slower time will pass for you. In neither frame of reference, though, would anyone feel anything special happening.

In fact, if you and i decided to race, and i ran at 19 km/h and you at 20 km/h, assuming we're both running perfectly in parallel, time would pass slower for you; more time will have elapsed for me. The amounts at which time would change, though, would be infinitesimal. The closer you get to 300 000 km/h, the slower time will pass for you, exponentially. I may be incorrect about this, but i think that at 99% of light speed (297 000 km/h), time would pass around 1000 time slower for any object traveling at that speed.

This same law says simply that at 0 km/h, time passes normally compared to the rest of the universe. And you can't go into minuses here. The only real meaning of giving a minus to a speed is that it will simply be in the opposite direction of whatever you're comparing it to. And to which direction you're going doesn't matter for time, all that does is the speed.

So it's not really that this law forbids time travel to the pass, it just doesn't mention it at all. This is why i didn't want to be definitive about saying that time travel to the past is impossible. Physics doesn't say it is. It also doesn't say it's impossible that fairies exist. I just don't have any reason to think that they do. I rather act that they don't. I rather act my life and live under the conditions i do know. I rather not bother myself with unknowns, especially those that make very little sense, to me. And among those is time travel. The logical implication of backwards time travel make it seem less possible than fairies, to be honest. I don't see any reason to give it merit, or to even talk about it. That is why i take a stance that it's practically sure it's not impossible.

In the same way i take a stance that although we don't know, i'm practically sure god doesn't exist. The only thing that can give me any information about it, the only thing that's left since there is no proof, logic, tells me i'm sure he/she/it doesn't exist. But i don't go around saying it, obviously, because i have no evidence for it and because it's an opinion. An opinion, although, which i find strong enough to live my life under the assumption it's correct. I feel the same about backwards time travel.

Sorry for this huge wall, but, damn you, you asked for it.

[rodroy323]

For time travel, you just need some plutonium and a flux capacitor.

[Fuzzzie]

And, as answer to this (and yes, I realize I am answering my our counter-argument, but bare with me), I propose that because physics as a science is relatively new, and we may discover that rules we felt were unbreakable, might have exceptions or addendum, yet to be found.

Some rules are fundamental functions of nature that you cannot alter though. You can cheat them and find ways around them, but the rules are constant. Without constant rules our universe would fall apart.

[cubby]

Well, not really computers, i was just extending the reach of the laws to include all of physics, and if the hardware is about anything, it's about physics. You could take another example, though. GPS would display your location wrongly, by a few dozen km, if the software didn't take into account the fact that time passes slower in orbit, where the satellites are, compared to where the information is being sent, due to 2 things: the satellite's speed relative to where it's being sent (30 000 km/h) and the fact it's farther from a gravitational source, which causes the spacetime around the satellite itself to be curved less, which in turn, along with the speed of travel, makes time pass slower compared to the surface of the Earth.

The theory that explains all of this is general relativity.



Well, first i should make this clear: What we in this thread and physicists or people in generally refer to when they say "time travel is possible" is actually not really time travel. It's just traveling faster in relation with the rest of the universe, or a specific place, like Earth, at speeds close to the speed of light. At these speeds, anyone in a hypothetical ship would feel time passing normally. Every single thing on the ship would be perfectly normal. Except, once it starts traveling at normal speeds again, the hypothetical person would find that "more" time has elapsed in the rest of the universe in comparison to the ship. The closer you get to 300 000 km/h, the faster time will pass for the rest of the universe in comparison to you, and therefor, the slower time will pass for you. In neither frame of reference, though, would anyone feel anything special happening.

In fact, if you and i decided to race, and i ran at 19 km/h and you at 20 km/h, assuming we're both running perfectly in parallel, time would pass slower for you; more time will have elapsed for me. The amounts at which time would change, though, would be infinitesimal. The closer you get to 300 000 km/h, the slower time will pass for you, exponentially. I may be incorrect about this, but i think that at 99% of light speed (297 000 km/h), time would pass around 1000 time slower for any object traveling at that speed.

This same law says simply that at 0 km/h, time passes normally compared to the rest of the universe. And you can't go into minuses here. The only real meaning of giving a minus to a speed is that it will simply be in the opposite direction of whatever you're comparing it to. And to which direction you're going doesn't matter for time, all that does is the speed.

So it's not really that this law forbids time travel to the pass, it just doesn't mention it at all. This is why i didn't want to be definitive about saying that time travel to the past is impossible. Physics doesn't say it is. It also doesn't say it's impossible that fairies exist. I just don't have any reason to think that they do. I rather act that they don't. I rather act my life and live under the conditions i do know. I rather not bother myself with unknowns, especially those that make very little sense, to me. And among those is time travel. The logical implication of backwards time travel make it seem less possible than fairies, to be honest. I don't see any reason to give it merit, or to even talk about it. That is why i take a stance that it's practically sure it's not impossible.

In the same way i take a stance that although we don't know, i'm practically sure god doesn't exist. The only thing that can give me any information about it, the only thing that's left since there is no proof, logic, tells me i'm sure he/she/it doesn't exist. But i don't go around saying it, obviously, because i have no evidence for it and because it's an opinion. An opinion, although, which i find strong enough to live my life under the assumption it's correct. I feel the same about backwards time travel.

Sorry for this huge wall, but, damn you, you asked for it.

This was great, read it all twice for proper digestion - thanks. I really appreciate it.

(hope you didn't mind my little joke above, I couldn't help myself)

[apepi]

Snip

I can see see your reasoning. Whenever I have no facts on something, I come to the conclusion that there is a 33% chance that it is correct, a 33% chance that it is incorrect and a 34% that is none of my previous answers.

Some rules are fundamental functions of nature that you cannot alter though. You can cheat them and find ways around them, but the rules are constant. Without constant rules our universe would fall apart.

If you can cheat/find other ways around them(rules) wouldn't those 'cheats' itself become part of the rule and not an expectation of it? I guess it is just all semantics...

[cubby]

Some rules are fundamental functions of nature that you cannot alter though. You can cheat them and find ways around them, but the rules are constant. Without constant rules our universe would fall apart.

I do hear what you are saying, but haven't there also already been documented cases of "exceptions" to physical laws? And at that point, do we not either rewrite the law (through scientific principle/process) or reevaluate the entire process.

And if we can cheat and find ways around constant rules, aren't they no longer constant?

Forgive my density, I swear I'm not trying to take the proverbial bull by the horns here, but I feel like I have a good grasp of the scientific method, and it always allows for new information to develop. I'm not trying to equate this process with "theories" like creationism or such, just to be clear.

[Dudemanguy]

The closest thing to hint time-travel to exist are telescopes.

Take the Pillars of Creation, for example. This Nebula is around 7,000 light years away from Earth. It has been deconstructed around 6000 years ago due to a shock wave produced from a Supernova. We can, however, still see it to this day. In another Millennium, we should be able to see it's deconstruction.

This doesn't prove that time-traveling exists, but it does hint that we can see through time. Perhaps Time travelling could exist in different terms, but I think it's unlikely.

We can see through the past. But if we can see through the future, it'll be a problem, but who knows.

[Fuzzzie]

I do hear what you are saying, but haven't there also already been documented cases of "exceptions" to physical laws? And at that point, do we not either rewrite the law (through scientific principle/process) or reevaluate the entire process.

Well, that's a different story. If we find evidence that our assumptions about the universe are incorrect then we do our best to match up our theories with reality. That's the ongoing process of science. At it's core however, the laws of nature are absolute. Our understanding of them is just an interpretation that may or may not be correct. That doesn't mean that we've violated the laws of nature.

And if we can cheat and find ways around constant rules, aren't they no longer constant?

Again, if our assumptions are wrong that's our problem, not the universes

[apepi]

The closest thing to hint time-travel to exist are telescopes.

Take the Pillars of Creation, for example. This Nebula is around 7,000 light years away from Earth. It has been deconstructed around 6000 years ago due to a shock wave produced from a Supernova. We can, however, still see it to this day. In another Millennium, we should be able to see it's deconstruction.

This doesn't prove that time-traveling exists, but it does hint that we can see through time. Perhaps Time travelling could exist in different terms, but I think it's unlikely.

We can see through the past. But if we can see through the future, it'll be a problem, but who knows.

You just sparked something in my head. If we go to that nebula(getting closer and closer to it), wouldn't we be somewhat see it in a 'fast forward' kind of perspective? The star would be destroyed when we get to it, but then then when we come back to Earth, we we see it in 'reverse' and by the time we come back from our perspective the nebula would still be alive. Would you guys count that as time travel?

Though we might have to be faster than the speed of light for this to happen?

[Fuzzzie]

You just sparked something in my head. If we go to that nebula(getting closer and closer to it), wouldn't we be somewhat see it in a 'fast forward' kind of perspective? The star would be destroyed when we get to it, but then then when we come back to Earth, we we see it in 'reverse' and by the time we come back from our perspective the nebula would still be alive. Would you guys count that as time travel?

It depends how fast you traveled towards it. If you were present for the explosion of a star 7000 light years away, traveled back to earth at the speed of light (assuming it's possible, it isn't) then you would witness everything you would see as if you were there when it would have happened.

When looking at our sun, you're seeing the sun as it was 8 minutes ago. If the sun blew up right now, we would have 8 minutes before we felt it's effects. Gravity, Radiation, Light all travel at c or less so it's not possible to relay information in any other way unless you use non-traditional means.

If you want to simulate time travel in this way, watch TV underwater. The light from the TV takes longer to pass through the water so you're essentially watching TV that is very, very fractionally older than current time.

[Dudemanguy]

You just sparked something in my head. If we go to that nebula(getting closer and closer to it), wouldn't we be somewhat see it in a 'fast forward' kind of perspective? The star would be destroyed when we get to it, but then then when we come back to Earth, we we see it in 'reverse' and by the time we come back from our perspective the nebula would still be alive. Would you guys count that as time travel?

Though we might have to be faster than the speed of light for this to happen?

I would have to say what Fuzzzie has said.

All I have to say is that light speed is that something about it feels very wrong. Perhaps going faster than light is possible, but it has unnatural effects. Just like the speed of sight, we can see things before it's light speed time. There is something interesting from light speed, but we cant just find it yet.

[Fuzzzie]

I would have to say what Fuzzzie has said.

All I have to say is that light speed is that something about it feels very wrong. Perhaps going faster than light is possible, but it has unnatural effects. Just like the speed of sight, we can see things before it's light speed time. There is something interesting from light speed, but we cant just find it yet.

Issues with traveling at lightspeed.

1. The faster you travel, the slower time moves. Traveling at the speed of light would essentially stop time as you know it.
2. The faster you travel. the more energy you need to keep going faster. As you approach the speed of light, the energy expenditure becomes infinite.
3. The faster you travel, the more mass you gain. An object traveling at the speed of light would have infinite mass.

[Wikiy]

Issues with traveling at lightspeed.

1. The faster you travel, the slower time moves. Traveling at the speed of light would essentially stop time as you know it.
2. The faster you travel. the more energy you need to keep going faster. As you approach the speed of light, the energy expenditure becomes infinite.
3. The faster you travel, the more mass you gain. An object traveling at the speed of light would have infinite mass.

Funny how the universe "chose" such an arbitrary and seemingly random number - 300 000 km/h - as the boundary for so many things.

[Fuzzzie]

Funny how the universe "chose" such an arbitrary and seemingly random number - 300 000 km/h - as the boundary for so many things.

There has to be a limit somewhere. Choosing an arbitrary number would cause chaos don't you think? Worse yet have it be random.