Sandman Posted March 24, 2003 Report Posted March 24, 2003 Hi, I've been wondering if Space-Time could be moving through a "fifth dimention", traveling at the speed of light. That would mean that the speed of light, is actually the speed of time.Could this explain why a photon that's accelerated past the speed of light is detected to exit a "room" before it enters ? Hope this makes some sort of sense.
Tormod Posted March 24, 2003 Report Posted March 24, 2003 Hi Sandman, and welcome to these forums! It's an interesting idea you have. I'm not sure I understand what you are thinking of when you say "the speed of time". To my knowledge it is not possible to speak of "time" in terms of velocity (well, it is of course possible to _speak_ of it, but I don't think it makes any sense... ) I have never heard of photons being accelerated past the speed of light. Do you have any links to articles or websites where I can read more about this? Tormod
Sandman Posted March 25, 2003 Author Report Posted March 25, 2003 Thanx for the warm welcome.What I mean by "speed of time" is this. If space-time is moving in some other "dimention", would it be possible to measure this velocity of this movement ? Maybe not from inside space-time, but from the outside it should be possible to see this hypothetical movement. Could you move faster than space-time ? Here's a link:http://www.space.com/scienceastronomy/generalscience/faster_than_c_000719.html
Tormod Posted March 25, 2003 Report Posted March 25, 2003 Sandman, this topic has actually been discussed before, click here to view the thread. The illustration which is mentioned in on of the postings shows it all, reall. The speed of light is not broken, but the different frequencies in the light beams actually give an illusion that the speed is broken. However, this "frequency wave" cannot carry any meaningful information, and although it appears to travel faster than light it actually travels _along_ the light beam, so there is no violation of the actual speed of c. Tormod
syndicated Posted March 25, 2003 Report Posted March 25, 2003 I don't think even in theory that would be possible. I mean I'm no astrophysicist by any means but wouldn't trying to "see" or quantify where space time is violate Heisenburg's Uncertainty principle? You couldn't possibly measure the speed or the location of something like time. As Im aware, time is simply a way of measuring and referencing events from one another. For all we know, another race of beings in this universe could use a completely different system for measuring such things, even more so if they were able to travel faster than the speed of light.But assuming that you could to some extent verify where space-time "is" in another dimension, and you were able to be on the outside looking at it, what would you use to reference it against? Like Stephen Hawking said, movement is relative to whatever it is you're measuring it against. ie. im not moving compared to my computer screen, but im moving pretty fast in relation to the sun, which is moving pretty fast compared to the centre of the galaxy and so on... Not to totally shut you down or anything.... lol... but your theory does raise a lot of interesting questions. But who knows? I may be completely wrong! Thanks for listening to my rant! Syn
Tormod Posted March 25, 2003 Report Posted March 25, 2003 Syndicated, that's hardly ranting... Welcome to you, too. I agree with you. There is probably no meaningful way to speak of "time" as something that can be measured as a fundamental "property" of anything. However, there is something called a "plack time", which is the minimum length of time which can separate two events. (Click here for a brief explanation of this). I did a hypography on time travel last year, it has some links on a varying speed of light theory. This is fast becoming hot stuff, and might eventually help us understand whether time can be related to the speed of light, and thus have a variable speed (I think even that phrase is meaningless, but hey - this is difficult stuff). http://www.hypography.com/topics/timetravel.cfm Tormod
deamonstar Posted March 31, 2003 Report Posted March 31, 2003 time travelling at the speed of light? sure, why not? to travel faster than light would bring you into the future... and to travel faster than time would also bring you into the future. traveling slower than time could bring you into the past.
Tormod Posted March 31, 2003 Report Posted March 31, 2003 Deamonstar, I have problems with that argument. If time travels at the speed of light, then _everything_ must travel at the speed of light as it moves through time. It doubles the equation, so that the speed of my hand moving from A to B is the time it takes (in my time-frame, say 5 seconds) PLUS the time it takes at the speed of light...doesn't make sense to me. If you could slow down time, you would move slower than light. You would not go backwards in time. That's like saying a runner which runs slower than the one before him is actually running backwards...! However, if you are right, and the slowing down of time brings you back in time - will it also bring _everything else_ back in time? Is there a "time horizon" which is only valid for the person moving slower than time? However, we know there is a link between the speed of light and the perception of passed time. Someone moving at relativistic speeds do indeed perceive that time is flowing at the _exact_ rate as I am even though I might be standing still - yet when we meet up, it turns out his clock has run much slower than mine. I might even have been dead for centuries when he steps out of his spaceship, him being only a few years older than he was when he left. I think the phrase "can something move faster than space-time" is meaningless. But it does bring a lot of strange ideas into my brain...great, Sandman...!
Sandman Posted March 31, 2003 Author Report Posted March 31, 2003 I'm glad I to be of service. If space-time is moving, at whatever speed, what you say is correct in that everything (in space-time) would be moving at that speed. An obsever inside space-time, would not notice (same as the bullet on the train scenarion (see http://www.howstuffworks.com))An observer inside space-time could also not make him/her -self travel slower than space-time. I disagree with the notion that if you move slower than space-time, you move into the past. I also don't know if you could move into the future. Let me explain:If you could move faster than space-time, you would simply arrive at your location (wherever that may be) before space-time could catch up. Would your location then be in the future ? For that to be true, the future would have to exist already. Also, does it not depend upon the DIRECTION, in theoretical five-dimentional space, not four dimentional space, in which you travel. If you travel in the oposite direction of space-time, you would arrive at a place where space-time has already been. Would that place you in the past ?Again it would depend upon wheter the past still "exists". I find it hard to beleive that the future is lying about, simply waiting for us to get there, or the past stays around after we've already been there. This, in my humble opinion does not rule out time-travel, but it seems to indicate that we cannot get to either simply by traveling at/faster than the speed of light. This has nothing to do with Einstein's time-dilation effects, however. Anyway, enough of this rant. I posted the original post, because I had an idea, not because I believe it to be true. You may shoot the crap out of my idea, or not, as you wish.
Tormod Posted March 31, 2003 Report Posted March 31, 2003 Hey, I wasn't shooting at your idea, I was aiming at deamonstar... No, seriously, I like your idea about an extra dimension in which space-time is unified, so that moving along this axis you can ask whether you actually move forwards or backwards in time *as it is perceived from the 4D space-time in which we exist*, *from the outside*. I fully agree with you in your last post. And keep posting your ideas. But - the idea of vieweing space-time from the outside is in fact not a new notion at all. Cosmologists often create visualisations of cosmic history by showing it like a "vase" with a pointed bottom - which represents the big bang. The vase then expands around the edge, which shows the size of the observable Universe. If you trace the vase with your finger from the bottom to the top, you follow the Universe through time. This 3D model is a simplification of the real cosmos. This is what Stephen Hawking writes about in chapter 3 of "The Universe in a nutshell". As for the speed of time - if you search Google for "speed of time" this entire discussion actually shows up on page 1 (at least it did so right now). How's that for speed of time! No, before I get too carried away...here's another view. Tormod
Tormod Posted March 31, 2003 Report Posted March 31, 2003 Sorry, that should have read *_or_ from the outside*. I can't get the edit message thingy to work...
deamonstar Posted April 9, 2003 Report Posted April 9, 2003 let's rephrase this as "time travels at the speed of GRAVITY"...
Tormod Posted April 14, 2003 Report Posted April 14, 2003 The speed of gravity was recently proved to be the speed of light...so I don't think we can say that the speed of time is the speed of gravity... Tormod
paultrr Posted December 3, 2004 Report Posted December 3, 2004 When we speak of space-time moving the general idea comes from the expansion of the universe itself. During inflation, and a simple search under that subject shows this, space-time moved or expanded actually FTL. In under 10^-39 seconds by the theory the universe increased in volume some 10^50th power. One of the odd things is space-time itself can move faster than light while information transfer within space-time, at least in our present vacuum state seems globally limited to C. To an extent if the current speed up in expasion holds true then eventually this odd case will hold true for the universe again one day. Anything that inflates can exceed a preset velocity limit like C. Its a volume change more than anything else that we refer to as space-time moving. Now objects moving within space-time are themselves subject to the C limit.
paultrr Posted December 3, 2004 Report Posted December 3, 2004 The inflationary scenario proposes that the vacuum energy was very large during a brief period early in the history of the Universe. When the Universe is dominated by a vacuum energy density the scale factor grows exponentially, a(t) = exp(H(t-to)). If the inflationary epoch lasts long enough the exponential function gets very large. This makes a(t) very large, and thus makes the radius of curvature of the Universe very large. What this does is it tends to flatten out space-time while expanding exponentially the volume. Inflation solves the horizon problem, because the future lightcone of an event that happens before inflation is expanded to a huge region by the growth during inflation. Thus, you end up with this huge volume that displays attributes as if it was casually connect. The expansion under some modifications to this basic theory started from a region no bigger across than the so-called Planck length (10^-35m), when the density was not infinite but "only" 10^94 grams per cubic centimetre. This kind of exponential expansion of space-time is exactly described in 1917, by one of the first cosmological models developed using the general theory of relativity, by Willem de Sitter. Einstein's original model was a static empty space-time. It neither collapsed or expanded. In the early 1920s it was realised that if a tiny amount of matter were added to the model (in the form of particles scattered throughout the space-time), they would recede from each other exponentially fast as the space-time expanded. Light takes 30 billionths of a second (3 x 10^-10 sec) to cross a single centimetre, and yet inflation expands the Universe from a size much smaller than a proton to 10 cm or larger across in only 15 x 10^-39 sec. This is possible because it is space-time itself that is expanding or moving, carrying matter along for the ride; nothing is moving through space-time faster than light under the standard inflation model. Indeed, it is because the expansion takes place so quickly that matter has no time to move. Thus, matter within space-time undergoes no inertia gain. Expansion of the cosmos was a process started by inflation. In some current runaway or accelerated expansion models it is the same power of original inflation that will eventually expand the universe fast enough so that almost nothing will be viewable one day.
paultrr Posted December 3, 2004 Report Posted December 3, 2004 Some of the current models today on propulsion(See Marc Mills as an example of ideas proposed) that explore ideas on how to exceed C are based simply upon harnessing the power of inflation and gravity or in some cases quantum effects. In these cases you get an effect that exceeds C, but one actually has such a craft not really undergoing any newtonian or relativistic acceleration at all. The general idea is to move space-time itself without actually accelerating the craft. As an example, Hawking in one of his books likened Alcubierre's original warp drive idea to shrinking the distance with gravity between the front of the craft to its destination and expanding the distance between the craft and its origin point. Its not a wormhole, but rather like shrinking and expanding space via harness gravity and inflation while the craft sits in a normal region of space-time. In most of the cases proposed its space-time itself that is moving. In a few cases, its the craft being moved by creating effects that attract and repell(Bias Drives & Diametric drives). However, that is the subject of another thread itself. But yes, space-time does move and in some cases under the right conditions it can move faster than light. So while time does matter, C is not always a restriction on such.
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