Is Faster Than Light travel the wrong question?

So, you're saying that once you reach the point of no time, there is no time in which to keep rotating the ruler? To what we currently experience. Our past becomes the future. People walk backwards...a episode of Red Dwarf actually kind of shows what this might be experienced like. True, but in all other dimensions, you can reverse course. Time, it would seem, is the only exception, and I'm just positing that this exception doesn't exist, and "rotating the ruler" is a way this may be possible. And yet, it seems in a temporal sense, we can only travel to miami, but we can't decide, halfway there, that we need to go back where we started from. In all other spacetime dimensions we can, but in this one we can't?

If I am not misunderstanding it myself, once you reach the point of not experiencing time, then yes.Think about it like this, we experience time at 300,000 m/s, however, if you were at that speed, then what would you be experiencing? But what we currently experience is not a universal now from which we can travel back in time from. Ah, it would seem so, but again, relativity says no.You have a place from which you started from - a "right here" that you started your journey from. But let me ask you, relative to the Sun, if you walk to Miami, are you going North or South? And if you turn around would you be headed in the other direction.Likewise, if you head to Miami, relative to the Sun, are you going up or down, left or right?So can you really reverse course, or does it just feel like you can?Remember, no universal space, time, direction, speed or size - it's all relative to the observer.- Oni

You're not moving north or south, but you are definitely moving in a direction, and can then reverse direction, regardless of the reference frame.

Right, but you are reversing direction from your frame of reference. But with no universal place in space, you are not moving from north then going south (or left/right, up/down). You are simply moving about in the spacial dimensions.Likewise, with time - you can reverse direction from your moment in time (hypothetically) but with no universal "time" frame, you are not going toward a future or leaving a past - its all one and the same. You are simply moving about in the time dimension.- Oni

Not true; since distance also plays a role in the force we don't need and Earth size mass to feel an Earth sized acceleration. With a compact mass equal to Everest such that we could stay 35 meters from it's center we'd feel a 1g force. At 10.25 meters We'd get 11g. We accelerate that at 10g and live in the nadir 1g point. The tidal forces would likely be a bit uncomfortable if we're much bigger than a soccer ball, but we can't have everything, now; can we?

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It's not the man that knows the most that has the most to say.

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Imagine yourself and an object with a gravitational pull of 5 G pulling you toward it. Now, we accelerate you and the object at 6 G. You will only feel 1 G. Suppose the object is pulling you at 7 G and you both are accelerated at 8 G. You will still only feel 1 G.

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Dwelling on this thought, suppose we possess neutron matter. The neutron matter is put in front of the ship. The more the ship accelerates, the closer you are automatically put toward the neutron mass. When you decelerate, the ship automatically pulls you away from the neutron matter.

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In which case you are not only accelerating the spaceship, but also the mini-neutron star. This takes immensely more energy than just accelerating the spaceship, only reinforcing the point that you would need a new, inexpensive energy source first. Also, the "neutron matter" needs to be far enough in front of the spaceship that its gravity gradient won't rip the ship and people apart.

All of this is correct, but there's more.You would have to continually adjust the distance to the object as you did your acceleration and deceleration. Unless you magically go from 0 g to, say, 20 g, while at the same time and just as magically bring the compensator from a safe distance to the correct distance to balance 20 g.I guess if you believe one you can believe the other, eh?Must be some other way to do all of this that we haven't thought of.

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Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

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But by claiming that we must travel through space the same way we do now is short-sighted and mired in the thinking of the past/present without considering new advances and discoveries that may be just over the horizon.

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It would be foolish to lock one's predictions to present-day technology. But it is equally foolish to think that our experimentally-verified understanding of relativity is completely wrong. And if our understanding of relativity is basically correct, physical travel (i.e. transportation of matter) with large accelerations requires a large amounts of energy. Like it or not, new technologies, new energy sources, or new physics cannot change this. The only way to change this is to disprove our experimentally-verified theories of relativistic dynamics.

Neither. Imagine you standing on the top floor of a skyscraper. Then both you and the Earth gets accelerated 2 G. You will only feel 1 G the opposite direction from the Earth.

Ah, got it! Neat idea.I suppose you would need the object to be of variable mass such that the delta in forces remains in the 1 - 5 G range or whatever's safe. Otherwise prior to acceleration you'd be experiencing the heavy Gs just from the gravity of what your standing on.

Hey guys, if it helps I just thought I'd chime in.
The basic idea is that relativity replaces absolute space and time with relative spacetime. The replacement of absolute with relative is something fairly straight forward. The replacement of space and time with spacetime is not.Let's take the example of not being able to move backwards in time. If I could move backwards in time I'd be able to stay where I am now, but go from 4pm to 3pm.
However it's the same with space, if I freeze time I can't go left or right or up or down, because to change your locaction in space requires motion and motion takes time.
So I can't stay in the same place and move backwards in time and I can't stay in the same time and move backwards in space.Of course there is the difference that I can take some time and eventually move backwards in space, where as I can't take some space and move backwards in time.
This is where spacetime becomes important. Basically we live in one giant structure (or more accurately shape) called spacetime. Points in spacetime are called events, with their locations labelled by space and time, basically when and where they are. The relativity basically comes from the fact that different observers can put different space and time labels on events.
However what all observers agree on is the geometry of spacetime. Spacetime has its own geometric rules which mean that certain events can never be connected, that is you can't pass from one event to another.One such example is travelling into your own past.
Let's say you want stay in the same place but travel to ten seconds ago, you obviously can't. For you the reason is because it's in the past.
For somebody moving past you at high speeds because they'll label events differently they'll see your "now" and your "ten seconds ago" as occuring at the same time, but at different points in space. For them the reason you can't move between these two events is because they occur at the same time and you don't have time to move between them.These are subjective reasons, the objective reason is that the events are not connected in spacetime. Not being able to move back in time is just one subjective way of viewing the disconnectedness of two events.

Hi SonGoku,Thanks for the detailed explanation. Question: No matter what, though, causality cannot be violated, right? If you don't mind, I'll try to explain it just to see if I understood it:Every observer will agree on the spacetime distance, but not necessariliy on the time it took between events - but, no matter what, the events can never be reversed. This would violate causality, right?Causality is an axiom of Minkowski spacetime, right?Also: Have I understood it correctly, that all moments in "time" already exist, and and since there's no universal time (just as there's no universal space) there is no point in time from where one could go back from?In other words, and bare with my layman explanations as this is just for my understanding - forward and backward in time are nonsensical terms in Einstein's model of spacetime (or Minkowski spacetime)...?Thanks again,- Oni

While we wait for Son Goku, doesn't this imply determinism or even fatalism?

Theories are an approximation of "reality" that become more aligned with "reality" as more observations are made. The are significant gaps in our knowledge of both quantum mechanics and relativity, and it is currently thought that both are incomplete pieces of a larger picture. It would truly be foolish to emphatically rule out any means of interstellar travel without further investigation.Furthermore, the current theories we have need not be proven completely incorrect to accommodate new possibilities. For example, just as Einstein modified Newtonian mechanics, so shall someone in the future modify Relativity.Edited by RickJB, : No reason given.Edited by RickJB, : No reason given.

Don't think of it philosophically, think of it in a dimension sense.Lets ignore time for a second (no pun intended, lol) - I could equally say all north/south - up/down - left/right already exist.North/south, up/down, left/right are subjective expressions of moving about in our spacial dimensions.Likewise, forward and backward in time are only subjective expressions of our experience in the time dimension.Intuitively we think there's a north/south up/down left/right, likewise, we intuitively think there's a forward and possible backward in time. But there isn't. Einstien's spacetime is dimensional, so there is no absolute point in space or time from where you can go north/south up/down left/right (in the spacial dimensions) -and- no forward/backwards (in the time dimension).What time describes is the distance between events (relative to the observer this time between events changes) - In SonGoku's example, for you it was ten seconds, but say for me travelling in an airplane above you they happened at the same "time".We both agree on the distance, we just disagree on the time it took to get there.But, one key thing to remember is the events themselves.Lets say the event was you walking from the front of your house(A) to the back of it(B) - (lets call it a distance of 100ft)No matter where the observer is (you at the events, me on a plane watching the event from above, or SonGoku on Venus) while we'll disagree on the time it took to get from position (A) to position (B), none of us will see them backwards (B happening before A).This would violate the axiom of causality that, if I'm not mistaken, cannot be violated in any geometry that describes our spacetime.- OniEdited by onifre, : No reason given.