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 Posted: Wed Oct 10, 2007 11:09 pm
....Well, maybe. I don't know, I don't have sufficient knowledge to properly assess this little theoretical physics news item: Quote: It don’t get much weirder than this. The universe is about to lose its dimension of time says a group of theoretical astrobods at the University of Salamanca in Spain. And they got the evidence to prove it. The idea comes from the study of braneworlds: the thinking that the universe we see around us is a 4-dimensional cosmos called a braneworld embedded in a multidimensional universe. The “signature” of our universe is the number of space and time-like dimensions it has: in our case we got 3 space-like dimensions and one time-like dimension. It’s what astrobods call a Lorentzian universe. So far so good: lots of astronutters think the same thing. But our universe may not always have been like this. Some theorists think it may once have had a Euclidean signature meaning that all the dimensions were space-like. Now Marc “Bars” Mars and a few pals in Spain say that the Universe’s signature might be about to flip from Lorentzian to Euclidean. In other words, our dimension of time is about turn space-like. Gulp! This ain’t entirely bonkers and here’s why. Bars Mars has calculated what it’s like to be an observer in a universe that is about to flip and get this: it would look as if it were expanding and accelerating away from us. Sound familiar? Yep, it’s exactly what astrobods have been observin over the last few years, a phenomenon they attribute to dark energy. If Bars Mars is right, dark energy ain’t got nothing to do with it and we’re all starin’ down the barrel of a cosmic catastrophe. Still, maybe four space-like dimensions will be better than three. Who needs time anyway? LinkI find this kind of hard to swallow. I mean, wouldn't the current time dimension becoming spacial force one of the spacial ones to become temporal in order to compensate? And I also doubt that the term "astrobod" is a real term in physics....
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Posted: Thu Oct 11, 2007 9:16 am
Astrobod. XD
Don't predictions like this get made every year?
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Posted: Thu Oct 11, 2007 1:14 pm
If you pass through an event horizon then time becomes space-like. Of course, in most event horizons the radial dimension becomes time-like, but still, it's not impossible as far as I know for only time to make the relevant switch. I think that's what happens with the Big Bang singularity.
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Posted: Thu Oct 11, 2007 2:28 pm
I move to officially set down the term "astrobod" into the literature. It can be followed by "hepbod", "quantbod", "phenomobod" and "theobod".
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Posted: Thu Oct 11, 2007 3:28 pm
A Lost Iguana I move to officially set down the term "astrobod" into the literature. It can be followed by "hepbod", "quantbod", "phenomobod" and "theobod". Cosmobod sounds a lot cooler. Relativi...um...bod doesn't quite work. Classibod, anyone? Ooh, electrobod sounds nice.
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Posted: Thu Oct 11, 2007 5:40 pm
astrobods ROFL
I think with the various apocalyptic predictions, we should just saddle up and take it.
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Posted: Thu Oct 11, 2007 8:44 pm
*shudders*
Astrobod will just lead to more cheesy pick-up lines.
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Posted: Sat Dec 29, 2007 11:29 pm
Hey, baby =P Wanna get with my astrobod tonight?
Well, now that I have successfully bastardized my first post in this guild, the question of being serious arises.
How the hell can we trust someone doing math about a time-less dimension, when the performance of the math itself took place over time? And he apparently calculated for speed (which requires time) and acceleration (which requires time squared). The theory is ridiculous. And stupid. All time does is give objects a method of existing in the exact same place with a physical separation. It's an apparatus through which our spatial position can be changed. Without time, we'd be confined to a single space. That would mean if we were to lose the dimension of time, everything in the universe would have a single position and a single coordinate.... always... no matter what.
Even the possibility of two time dimensions seems absurd. At first it sounds like a very believable and tangible idea. You simple imagine time as a unit of space and plot in your head a simple x-y coordinate plane. You can then imagine a box moving out in all directions along this plane. However to have two dimensions of time would specify infinite lines of time (as opposed to a single line that we currently have). This would mean that not only can two objects occupy the same space (given different times) but that two objects can occupy the same space at the same time given a different secondary time. Perhaps there is a way in which this is possible that escapes my 4-dimensional thinking, however having infinite objects in infinite places at infinite times seems like it would cause a paradox somewhere. Especially when you're in the past and the future at the same time 3nodding Perception just wouldn't be too possible.
If I said you had a hot astrobod, would you hold it against me?
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Posted: Sun Dec 30, 2007 7:58 am
spider_desu Hey, baby =P Wanna get with my astrobod tonight? Well, now that I have successfully bastardized my first post in this guild, the question of being serious arises. How the hell can we trust someone doing math about a time-less dimension, when the performance of the math itself took place over time? And he apparently calculated for speed (which requires time) and acceleration (which requires time squared). The theory is ridiculous. And stupid. All time does is give objects a method of existing in the exact same place with a physical separation. It's an apparatus through which our spatial position can be changed. Without time, we'd be confined to a single space. That would mean if we were to lose the dimension of time, everything in the universe would have a single position and a single coordinate.... always... no matter what. Even the possibility of two time dimensions seems absurd. At first it sounds like a very believable and tangible idea. You simple imagine time as a unit of space and plot in your head a simple x-y coordinate plane. You can then imagine a box moving out in all directions along this plane. However to have two dimensions of time would specify infinite lines of time (as opposed to a single line that we currently have). This would mean that not only can two objects occupy the same space (given different times) but that two objects can occupy the same space at the same time given a different secondary time. Perhaps there is a way in which this is possible that escapes my 4-dimensional thinking, however having infinite objects in infinite places at infinite times seems like it would cause a paradox somewhere. Especially when you're in the past and the future at the same time 3nodding Perception just wouldn't be too possible. If I said you had a hot astrobod, would you hold it against me? In this case, "time" is used in the entirely formal relativistic sense, as part of the relativistic distance metric. All it's saying is that the geometry of space-time might change significantly at some point, and that "time" will change its nature, not that time will disappear. As for the topic of multiple time dimensions, once again this is "time-like" in the purely formal sense of the distance metric; it is a pair of dimensions that act in a time-like manner according to the distance metric, although perhaps not in terms of causality or entropy. The problem of causality comes into play only if one posits causality along both temporal dimensions but directionality along only one. In other words, if we had two "time-like" dimensions and were being forced forward along both, then we wouldn't have a problem. Of course, the idea of "forward" becomes somewhat problematic, but such a problem would erase strict causality as well.
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Posted: Wed Jan 02, 2008 5:11 pm
Layra-chan spider_desu Hey, baby =P Wanna get with my astrobod tonight? Well, now that I have successfully bastardized my first post in this guild, the question of being serious arises. How the hell can we trust someone doing math about a time-less dimension, when the performance of the math itself took place over time? And he apparently calculated for speed (which requires time) and acceleration (which requires time squared). The theory is ridiculous. And stupid. All time does is give objects a method of existing in the exact same place with a physical separation. It's an apparatus through which our spatial position can be changed. Without time, we'd be confined to a single space. That would mean if we were to lose the dimension of time, everything in the universe would have a single position and a single coordinate.... always... no matter what. Even the possibility of two time dimensions seems absurd. At first it sounds like a very believable and tangible idea. You simple imagine time as a unit of space and plot in your head a simple x-y coordinate plane. You can then imagine a box moving out in all directions along this plane. However to have two dimensions of time would specify infinite lines of time (as opposed to a single line that we currently have). This would mean that not only can two objects occupy the same space (given different times) but that two objects can occupy the same space at the same time given a different secondary time. Perhaps there is a way in which this is possible that escapes my 4-dimensional thinking, however having infinite objects in infinite places at infinite times seems like it would cause a paradox somewhere. Especially when you're in the past and the future at the same time 3nodding Perception just wouldn't be too possible. If I said you had a hot astrobod, would you hold it against me? In this case, "time" is used in the entirely formal relativistic sense, as part of the relativistic distance metric. All it's saying is that the geometry of space-time might change significantly at some point, and that "time" will change its nature, not that time will disappear. As for the topic of multiple time dimensions, once again this is "time-like" in the purely formal sense of the distance metric; it is a pair of dimensions that act in a time-like manner according to the distance metric, although perhaps not in terms of causality or entropy. The problem of causality comes into play only if one posits causality along both temporal dimensions but directionality along only one. In other words, if we had two "time-like" dimensions and were being forced forward along both, then we wouldn't have a problem. Of course, the idea of "forward" becomes somewhat problematic, but such a problem would erase strict causality as well. But if two "times" existed, then would we be forced along each at a constant rate, just as we are forced along our current time-line at a constant rate? Or would one be under the influence of external forces, just as our spatial dimensions are? Can the value of one time be changed relative to the other? Or do each continue to move? If there are two dimensions of time and each progress in straight lines and each progress at constant rates, regardless of what the rate is since they have similar derivatives one could imagine that a direct constant proportionality exists at all times to compare the two functions [f(x) = k*g(x)]. In this sense, as far as any observer is concerned, the two progress along-side each other and any changes in one are related directly to changes in the other. Thus, how could one ever perceive a difference between the two? Hell- we could have two dimensions of time in our own universe progressing at constant rates. When something happens at t=2 seconds on one time-line it occurs at t=6 seconds on the other. But since t=3 on the first is the same as t=9 on the other, we would only observe a single change and a single time. The only conceivable way that two dimensions of time would have an effect on the world around them is if the two had non-constant rates. And as it is, times seems pretty perpetual and constant. Theoretically we can speed time for a particle by accelerating it (and thus speed time for an area or volume by accelerating all particles within it) but this effect would be recognized on BOTH time lines, yes? Unless... perhaps one time line were synchronized with the x-axis and another with the y-axis? rolleyes That's just getting ridiculous, though. People would be stretched and contorted in the strangest ways.
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Posted: Thu Jan 03, 2008 7:11 am
spider_desu Layra-chan In this case, "time" is used in the entirely formal relativistic sense, as part of the relativistic distance metric. All it's saying is that the geometry of space-time might change significantly at some point, and that "time" will change its nature, not that time will disappear. As for the topic of multiple time dimensions, once again this is "time-like" in the purely formal sense of the distance metric; it is a pair of dimensions that act in a time-like manner according to the distance metric, although perhaps not in terms of causality or entropy. The problem of causality comes into play only if one posits causality along both temporal dimensions but directionality along only one. In other words, if we had two "time-like" dimensions and were being forced forward along both, then we wouldn't have a problem. Of course, the idea of "forward" becomes somewhat problematic, but such a problem would erase strict causality as well. But if two "times" existed, then would we be forced along each at a constant rate, just as we are forced along our current time-line at a constant rate? Or would one be under the influence of external forces, just as our spatial dimensions are? Can the value of one time be changed relative to the other? Or do each continue to move? If there are two dimensions of time and each progress in straight lines and each progress at constant rates, regardless of what the rate is since they have similar derivatives one could imagine that a direct constant proportionality exists at all times to compare the two functions [f(x) = k*g(x)]. In this sense, as far as any observer is concerned, the two progress along-side each other and any changes in one are related directly to changes in the other. Thus, how could one ever perceive a difference between the two? Hell- we could have two dimensions of time in our own universe progressing at constant rates. When something happens at t=2 seconds on one time-line it occurs at t=6 seconds on the other. But since t=3 on the first is the same as t=9 on the other, we would only observe a single change and a single time. The only conceivable way that two dimensions of time would have an effect on the world around them is if the two had non-constant rates. And as it is, times seems pretty perpetual and constant. Theoretically we can speed time for a particle by accelerating it (and thus speed time for an area or volume by accelerating all particles within it) but this effect would be recognized on BOTH time lines, yes? Unless... perhaps one time line were synchronized with the x-axis and another with the y-axis? rolleyes That's just getting ridiculous, though. People would be stretched and contorted in the strangest ways. Well, if we are taking time to have a relativistic meaning, then people actually are forced through time at non-constant rates; for the most part, the relevant equation is  where we consider t to be the person's time coordinate and the x with an arrow to denote their spatial coordinate vector (c being the speed of light). Hence the derivative of t with respect to s is the rate of time passing, and the derivative of x with respect to s is the relativistic velocity. Usually this is expressed as the distance metric. We don't notice the changes in our temporal velocity because we're not designed to and the changes are very small for the speeds that we go at. So if we do have two temporal dimensions, then we would have to consider a two-dimensional temporal vector for our temporal velocity and a three-dimensional spatial vector for our spatial velocity, and we'd end up with |ct|^2-|x|^2 =1 again. Hence we could have people moving differently through the temporal plane but moving in the same manner through space. I'm not sure how much direct physical sense this makes, but it could theoretically be observable without causing causality violations.
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Posted: Thu Jan 03, 2008 8:33 am
Oh no, not the Millerites again! gonk Only this time they're science nuts instead of religious nuts. sad
Of course, this could happen... if the premise they're basing it on is correct. If it isn't, no dice.
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Posted: Thu Jan 03, 2008 11:42 pm
Here's another way time is more relative than most of us even think: Quote: The age of the universe also depends on where you're standing, as Wiltshire discovered in calculations published in the New Journal of Physics. The universe is 14.7 billion years old, a billion years older than the currently accepted age, from our galactic observation point. But it is more than 18 billion years old from an average location in a void. In a third paper, published this week in Astrophysical Journal Letters, Wiltshire and colleagues examine independent observational tests that confirm these ages. Link
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Posted: Fri Jan 04, 2008 3:20 pm
Bwehehe, I had to throw this out there. My girlfriend's senior thesis advisor, Gott, took his kids hiking in the mountains. They brought with them one atomic clock, and left one at the foot. After a week in the mountains, they came back down, and he got to show his kids that time speeds up at higher altitudes.
(Sorry for the irrelevance)
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Posted: Fri Jan 04, 2008 7:19 pm
Swordmaster Dragon Bwehehe, I had to throw this out there. My girlfriend's senior thesis advisor, Gott, took his kids hiking in the mountains. They brought with them one atomic clock, and left one at the foot. After a week in the mountains, they came back down, and he got to show his kids that time speeds up at higher altitudes. (Sorry for the irrelevance) That is frankly awesome.
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