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I thought once you have space, your have time. Its like a unit of measure between distances.
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WHAT IF WE ALREADY INVENTED TIME TRAVEL................
- Thread in 'General' Thread starter Started by nawghtyhare,
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This is all so interestingly confusing.
I'm extremely intrigued, but the language for me in regards to this discussion is just a bit over my head for now
Need english translation
I'm extremely intrigued, but the language for me in regards to this discussion is just a bit over my head for now
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Another explanation
Prior to Einstein, the world was used to thinking of space as this fixed three-dimensional grid that we move through. Think of a gigantic box that contains the whole universe. And we thought of time as a linear track that we were on, moving forward into the future, away from the past. So imagine this big box that contains the universe (space) now being set on a set of train tracks, and moving forward in a straight line, at a constant speed.
On this picture, you can move around in space all you want, but it's just a bare fact about the universe that it's all moving forward in time at the same rate. Whyyou can't go back in time is sort of an unanswerable question. It's just a basic fact about the universe that everything's moving forward through time at a constant rate. You can't change that any more than you can change that matter takes up space, protons have positive charge, etc. And there's no more explanation for that fact than "well, that's just the way things are."
Enter Einstein. Einstein (and others, but we'll keep the story simple) suggests a very different picture of space and time. Rather than being two separate things - space being the 3d grid we move through, and time being a linear track we're going down - Einstein suggests that space and time are really a single, unified thing.
Just as you can have a two dimensional space (a flat plane - a grid with only length and width, like a sheet of paper), you can add an extra dimension to it - height - to have a three-dimensional space with length, width, and depth.
Einstein suggests that time is just a fourth spatial dimension that we add to the three-dimensional space we're used to thinking about. This is hard to picture in the way you picture a third dimension being added to a 2d space, but picturing it visually isn't very important so just stick with me. All you need to keep in mind is the idea that time is just like an extra spatial dimension. And, just as the addition of a third dimension to a flat plane creates the three-dimensional manifold we call real space; the addition of this fourth dimension to real space creates a four-dimensional manifold that we call space-time.
So, we used to think of time as a track that everything moved down at a constant rate. We can now think of every object as being situated inside this 4D manifold called space-time. And, further, we can think of every object as having a constant speed that it's moving at. Why do objects move at a constant speed? That's an incredibly complex question of physics, and we'll leave it aside. Just take it as granted that we've discovered, empirically, that objects all seem to move at a constant rathe through this 4D manifold of space-time.
But, you don't feel like you're moving, right? You're probably sitting still. And you can control the speed at which you move too. You can run, drive, walk, sit, etc. So how is it that you have a constant speed through space-time?
Well, to understand this, look at this image.
View media item 1581253
Imagine that you're that dot, and that the forward (y) axis is time, and the horizontal (x) axis is space. You're moving at a constant speed through this space-time manifold, and there's nothing you can do about that. The speed is fixed. What you can change, however, is the direction you move through space-time. You can move more in the x direction or more in the y direction, though you'll stay at the same constant speed, no matter what you do.
This sounds funky, but the basic meaning is this. When you move through space, you are diverting some of your space-time speed away from movement in the forward (time) direction to movement in the horizontal (space) direction. So, imagine you're sitting, and then you get up to go to the kitchen. When you were sitting, all of your space-time momentum was moving you through time. You weren't moving through space at all. When you got up and walked to the kitchen though, you diverted some of the speed at which you were moving through time to your movement through space. You moved a bit more slowly forward in time, so that you could move through space.
Now, if instead of walking slowly to the kitchen, you had sprinted to the kitchen, you would have diverted even more of your space-time speed into movement through space, and thus would have made even less progress forward through time during your trip to the kitchen than if you had walked.
This illustrates the fact that the faster you move through space, the slower you move through time. And, conversely, the slower you move through space, the faster you move through time.
So now, remember that constant speed I said you (and everything else) were moving at through space-time? That constant speed that everything is moving at is just one of many 'constant' facts about the universe. Other constants are things like the mass of an electron, the charge of a proton, etc. These constants are basic facts about the universe that we've discovered. We're not sure why these facts are the way they are, but they seem like basic, unalterable facts about the universe.
There's a name - or at least a symbol - for this constant speed we're all travelling through space-time. It's notated with C. But just how fast is this speed we're moving through space-time? Well, it's the speed of light. That's what C is. When you sit down, you're moving at the speed of light (186,000 miles per second) through space-time. And all of that motion is in the forward (time) direction. When you get up and get a coke, you divert a tiny, tiny bit of that speed (say, two miles an hour?) to movement through space. And when you sit back down, those 2mph are returned to movement through time.
So, remembering that this speed at which we move through space-time is a constant fact of nature, much like the mass of an electron, we can ask your question anew: Why can't we travel through time?
Well, the answer is now very complex. We obviouslycan move through time. We're doing it right now, at nearly the speed of light. And we can alter the speed at which we move through time by moving through space at different rates.
But your question is presumably whether we can know with confidence that we can't go backward or jump forward in time. It seems that we can't. The reason is that, just in the way we can't make electrons that have different masses than they naturally do, because the mass of an electron is a fixed, constant fact about the universe; neither can we make objects that move through space-time at any different rate than they naturally do, because the speed at which all objects move through space-time is fixed at C. C is a constant that we don't know how to manipulate (and are currently most tempted to think is not manipulable).
What we can do, however, is divert more or less of our speed through space-time in the space direction. If we diverted half our speed through time to speed through space (by travelling at half the speed of light) we would move through time half as fast. If we diverted all of our speed through time into speed through space (by travelling at the speed of light), then we would cease to move through time at all. Time, for us, would 'stop'. But what this really means is that wewould stop moving through time.
On this picture, you can move around in space all you want, but it's just a bare fact about the universe that it's all moving forward in time at the same rate. Whyyou can't go back in time is sort of an unanswerable question. It's just a basic fact about the universe that everything's moving forward through time at a constant rate. You can't change that any more than you can change that matter takes up space, protons have positive charge, etc. And there's no more explanation for that fact than "well, that's just the way things are."
Enter Einstein. Einstein (and others, but we'll keep the story simple) suggests a very different picture of space and time. Rather than being two separate things - space being the 3d grid we move through, and time being a linear track we're going down - Einstein suggests that space and time are really a single, unified thing.
Just as you can have a two dimensional space (a flat plane - a grid with only length and width, like a sheet of paper), you can add an extra dimension to it - height - to have a three-dimensional space with length, width, and depth.
Einstein suggests that time is just a fourth spatial dimension that we add to the three-dimensional space we're used to thinking about. This is hard to picture in the way you picture a third dimension being added to a 2d space, but picturing it visually isn't very important so just stick with me. All you need to keep in mind is the idea that time is just like an extra spatial dimension. And, just as the addition of a third dimension to a flat plane creates the three-dimensional manifold we call real space; the addition of this fourth dimension to real space creates a four-dimensional manifold that we call space-time.
So, we used to think of time as a track that everything moved down at a constant rate. We can now think of every object as being situated inside this 4D manifold called space-time. And, further, we can think of every object as having a constant speed that it's moving at. Why do objects move at a constant speed? That's an incredibly complex question of physics, and we'll leave it aside. Just take it as granted that we've discovered, empirically, that objects all seem to move at a constant rathe through this 4D manifold of space-time.
But, you don't feel like you're moving, right? You're probably sitting still. And you can control the speed at which you move too. You can run, drive, walk, sit, etc. So how is it that you have a constant speed through space-time?
Well, to understand this, look at this image.
View media item 1581253
Imagine that you're that dot, and that the forward (y) axis is time, and the horizontal (x) axis is space. You're moving at a constant speed through this space-time manifold, and there's nothing you can do about that. The speed is fixed. What you can change, however, is the direction you move through space-time. You can move more in the x direction or more in the y direction, though you'll stay at the same constant speed, no matter what you do.
This sounds funky, but the basic meaning is this. When you move through space, you are diverting some of your space-time speed away from movement in the forward (time) direction to movement in the horizontal (space) direction. So, imagine you're sitting, and then you get up to go to the kitchen. When you were sitting, all of your space-time momentum was moving you through time. You weren't moving through space at all. When you got up and walked to the kitchen though, you diverted some of the speed at which you were moving through time to your movement through space. You moved a bit more slowly forward in time, so that you could move through space.
Now, if instead of walking slowly to the kitchen, you had sprinted to the kitchen, you would have diverted even more of your space-time speed into movement through space, and thus would have made even less progress forward through time during your trip to the kitchen than if you had walked.
This illustrates the fact that the faster you move through space, the slower you move through time. And, conversely, the slower you move through space, the faster you move through time.
So now, remember that constant speed I said you (and everything else) were moving at through space-time? That constant speed that everything is moving at is just one of many 'constant' facts about the universe. Other constants are things like the mass of an electron, the charge of a proton, etc. These constants are basic facts about the universe that we've discovered. We're not sure why these facts are the way they are, but they seem like basic, unalterable facts about the universe.
There's a name - or at least a symbol - for this constant speed we're all travelling through space-time. It's notated with C. But just how fast is this speed we're moving through space-time? Well, it's the speed of light. That's what C is. When you sit down, you're moving at the speed of light (186,000 miles per second) through space-time. And all of that motion is in the forward (time) direction. When you get up and get a coke, you divert a tiny, tiny bit of that speed (say, two miles an hour?) to movement through space. And when you sit back down, those 2mph are returned to movement through time.
So, remembering that this speed at which we move through space-time is a constant fact of nature, much like the mass of an electron, we can ask your question anew: Why can't we travel through time?
Well, the answer is now very complex. We obviouslycan move through time. We're doing it right now, at nearly the speed of light. And we can alter the speed at which we move through time by moving through space at different rates.
But your question is presumably whether we can know with confidence that we can't go backward or jump forward in time. It seems that we can't. The reason is that, just in the way we can't make electrons that have different masses than they naturally do, because the mass of an electron is a fixed, constant fact about the universe; neither can we make objects that move through space-time at any different rate than they naturally do, because the speed at which all objects move through space-time is fixed at C. C is a constant that we don't know how to manipulate (and are currently most tempted to think is not manipulable).
What we can do, however, is divert more or less of our speed through space-time in the space direction. If we diverted half our speed through time to speed through space (by travelling at half the speed of light) we would move through time half as fast. If we diverted all of our speed through time into speed through space (by travelling at the speed of light), then we would cease to move through time at all. Time, for us, would 'stop'. But what this really means is that wewould stop moving through time.
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The theory of parallel universes is amazing to me! Maybe there have been cases of people experiencing other dimensions/ realms.
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View media item 1581310
Say werd
Say werd
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Btw time is simply a unit of measure, which we created...so time doesn't really mean anything...crazy thought to process...lol
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i read this thread before
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Nas warned us
i read this thread before
Bro I ain't even gonna lie, I was just about to post this.Everything from everyone's post, to who's posting, resembles something I've read already.
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Smh woa
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Yeah, let's not go there. Most of us aren't well versed in physics to say something like that.
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This is all so interestingly confusing.
I'm extremely intrigued, but the language for me in regards to this discussion is just a bit over my head for now
there's a sub on reddit called ELI5 where subjects like this and others get a good breakdown.
Theory of relativity breakdown (someone was going to see Interstellar and had questions)
If you're traveling North at some speed for some amount of time, you go some distance North. Likewise, going East at the same speed for the same amount of time makes you go the same distance East. But if you go NorthEast at the same speed for the same amount of time, you don't go quite as far North as you did when going purely North, and you don't go quite as far East as you did going purely East.
Time and space work the same way. Imagine, instead of North and East on a graph, time and space. The more you travel through space (the faster you go), the less you travel through time. Which agrees with the Theory of Relativity: the closer you get to the speed of light, the slower time moves for you. Also, the less you travel through space (the slower you go), the more you travel though time- that would only make sense.
The most important piece of information that your mom needs to understand in order to enjoy the movie: gravity and acceleration both have the same effects on an object in terms of time. If you go really fast, time moves slowly for you. Likewise, if you're experiencing a lot of gravitational pull, time moves slowly for you. You could even think of gravity and acceleration as the same thing. Say you're in an elevator in space: If the elevator starts accelerating in some direction, you will be pushed up against a wall and experience an illusion of gravity.
Time and space work the same way. Imagine, instead of North and East on a graph, time and space. The more you travel through space (the faster you go), the less you travel through time. Which agrees with the Theory of Relativity: the closer you get to the speed of light, the slower time moves for you. Also, the less you travel through space (the slower you go), the more you travel though time- that would only make sense.
The most important piece of information that your mom needs to understand in order to enjoy the movie: gravity and acceleration both have the same effects on an object in terms of time. If you go really fast, time moves slowly for you. Likewise, if you're experiencing a lot of gravitational pull, time moves slowly for you. You could even think of gravity and acceleration as the same thing. Say you're in an elevator in space: If the elevator starts accelerating in some direction, you will be pushed up against a wall and experience an illusion of gravity.
Another write up about spacetime and light travel.
Everything, by nature of simply existing, is "moving" at the speed of light (which really has nothing to do with light: more on that later). Yes, that does include you.
Our understanding of the universe is that the way that we perceive space and time as separate things is, to be frank, wrong. They aren't separate: the universe is made of "spacetime," all one word. A year and a lightyear describe different things in our day to day lives, but from a physicist's point of view, they're actually the exact same thing (depending on what kind of physics you're doing).
In our day to day lives, we define motion as a distance traveled over some amount of time. However, if distances and intervals of time are the exact same thing, that suddenly becomes completely meaningless. "I traveled one foot for every foot that I traveled" is an absolutely absurd statement!
The way it works is that everything in the universe travels through spacetime at some speed which I'll call "c" for the sake of brevity. Remember, motion in spacetime is meaningless, so it makes sense that nothing could be "faster" or "slower" through spacetime than anything else. Everybody and everything travels at one foot per foot, that's just... how it works.
Obviously, though, things do seem to have different speeds. The reason that happens is that time and space are orthogonal, which is sort of a fancy term for "at right angles to each other." North and east, for example, are orthogonal: you can travel as far as you want directly to the north, but it's not going to affect where you are in terms of east/west at all.
Just like how you can travel north without traveling east, you can travel through time without it affecting where you are in space. Conversely, you can travel through space without it affecting where you are in time.
You're (presumably) sitting in your chair right now, which means you're not traveling through space at all. Since you have to travel through spacetime at c (speed of light), though, that means all of your motion is through time.
By the way, this is why time dilation happens: something that's moving very fast relative to you is moving through space, but since they can only travel through spacetime at c, they have to be moving more slowly through time to compensate (from your point of view).
Light, on the other hand, doesn't travel through time at all. The reason it doesn't is somewhat complicated, but it has to do with the fact that it has no mass.
Something that isn't moving that has mass can have energy: that's what E = mc2 means. Light has no mass, but it does have energy. If we plug the mass of light into E=mc2, we get 0, which makes no sense because light has energy. Hence, light can never be stationary.
Not only that, but light can never be stationary from anybody's perspective. Since, like everything else, it travels at c through spacetime, that means all of its "spacetime speed" must be through space, and none of it is through time.
So, light travels at c. Not at all by coincidence, you'll often hear c referred to as the "speed of light in a vacuum." Really, though, it's the speed that everything travels at, and it happens to be the speed that light travels through space at because it has no mass.
Our understanding of the universe is that the way that we perceive space and time as separate things is, to be frank, wrong. They aren't separate: the universe is made of "spacetime," all one word. A year and a lightyear describe different things in our day to day lives, but from a physicist's point of view, they're actually the exact same thing (depending on what kind of physics you're doing).
In our day to day lives, we define motion as a distance traveled over some amount of time. However, if distances and intervals of time are the exact same thing, that suddenly becomes completely meaningless. "I traveled one foot for every foot that I traveled" is an absolutely absurd statement!
The way it works is that everything in the universe travels through spacetime at some speed which I'll call "c" for the sake of brevity. Remember, motion in spacetime is meaningless, so it makes sense that nothing could be "faster" or "slower" through spacetime than anything else. Everybody and everything travels at one foot per foot, that's just... how it works.
Obviously, though, things do seem to have different speeds. The reason that happens is that time and space are orthogonal, which is sort of a fancy term for "at right angles to each other." North and east, for example, are orthogonal: you can travel as far as you want directly to the north, but it's not going to affect where you are in terms of east/west at all.
Just like how you can travel north without traveling east, you can travel through time without it affecting where you are in space. Conversely, you can travel through space without it affecting where you are in time.
You're (presumably) sitting in your chair right now, which means you're not traveling through space at all. Since you have to travel through spacetime at c (speed of light), though, that means all of your motion is through time.
By the way, this is why time dilation happens: something that's moving very fast relative to you is moving through space, but since they can only travel through spacetime at c, they have to be moving more slowly through time to compensate (from your point of view).
Light, on the other hand, doesn't travel through time at all. The reason it doesn't is somewhat complicated, but it has to do with the fact that it has no mass.
Something that isn't moving that has mass can have energy: that's what E = mc2 means. Light has no mass, but it does have energy. If we plug the mass of light into E=mc2, we get 0, which makes no sense because light has energy. Hence, light can never be stationary.
Not only that, but light can never be stationary from anybody's perspective. Since, like everything else, it travels at c through spacetime, that means all of its "spacetime speed" must be through space, and none of it is through time.
So, light travels at c. Not at all by coincidence, you'll often hear c referred to as the "speed of light in a vacuum." Really, though, it's the speed that everything travels at, and it happens to be the speed that light travels through space at because it has no mass.
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