Justin, I do think there is a difference between the universe and infinity. We have no idea whether or not the universe we seem to be a part of is all there is unless you are assigning infinity to our universe, but there is no evidence for it. As an example, we have no idea where black holes might lead, if they lead anywhere at all, but if they do lead somewhere it just might be another universe. As such I find it difficult to consider the universe we know as being all inclusive.
You also mention that pursuant to current observations the universe is expanding which leads me to ask expanding into what. For the universe to expand it has to have boundaries beyond which it is expanding therefore postulating something else outside the boundaries of our universe. Just as infinity, a concept created by human beings, is unprovable and unknowable -- at least in our current state of awareness and being. Ideas and theories such as this are for us nothing more than mental playtoys. Such as it is with your statement that nothing can go faster than light. According to the theories and postulations we currently possess it appears that nothing can go faster than light, but even that is a very narrow statement because we know so little about the universe. On Aug 26, 2:53 am, Justintruth <[email protected]> wrote: > According to relativity spacetime is a continuum. A set can be be > infinite, finite and unbounded, or finite and bounded. The case of > finite and bounded is excluded for current theory, and maybe > necessarily so since the term "universe" is all inclusive so it would > include whatever was on the other side of the boundary. That leaves > the cases of infinite or finite and unbounded. > > The idea of finite and unbounded is like a basketball surface. It has > no edge even though it is not infinite like a plane. If the universe > were finite and unbounded and spherical then no matter which direction > in space you went you would end up back where we are. Something like > that may in fact be the case. > > Whether the universe is finite and unbounded or infinite is a question > the answer to which is not currently scientifically known. My > understanding is that the recent observations include a universe that > is expanding at an increasing rate. If that is true then the universe > is no longer behaving like current scientific theories predict and the > theoretical physicists have work to do. > > If you want to know what a continuum is consider this... Imagine a > point on a plane. Now imagine a small disc around that point. Now > imagine a smaller disc. For every disc size you give me, if there is a > continuum, I can find a smaller disc that is made up of points in the > continuum. So if you draw a 1 inch circle then I can draw a 1/2 inch > circle and if you draw a 1/2 circle I can draw a 1/4 inch circle etc. > If that is true for every point then the set of points is continuous. > The only problem with this idea is if there is a boundary point. If > you choose a point on the boundary you cannot draw a circle all the > way around but you could draw something like a half circle. But we are > excluding bound sets so no problem! There are better more formal > definitions on the internet in the wiki. > > Now imagine a line segment with a start and endpoint ... say the > points on a line from zero to one. Then that set has a boundary. The > points zero is one boundary and the point one is another. But if you > take the line segment from zero to one and then exclude the point zero > and the point one you now have an unbounded set! > > The numbers 1, 2, 3 etc are not a continuum because if you take the > number 2 for example and I give you the number 1 for example you can't > find a neighborhood around 2 that is closer to 2 than 1 but contains 2 > and other numbers. But fractions are a continuum because if you give > the number 2 for example and I give you the number 1 for example then > you can say "all the points from 1 and 1/2 to the 2" All those points > are closer to 2 than 1. If I give you 1 1/2 then you give me 1 3/4. > Now try to find a number that that doesn't work for.... If I give you > 1.9you give me 1.99. If I give you 1.99 you give me 1.999 etc. If I > give you 1.999999999 you give 1.9999999999! > > In fact there was some theoretical work in physics that postulated > that time and space were not continuous but were discreet or > quantized. As far as I know the work never gelled into an acceptable > theory. > > What is interesting is the relationship between time and space. > Spacetime was a 4 dimensional continuum before Einstiein. What he > found was that what is for one person two points or events imagined at > the same time but separated by a distance and that therefore determine > a length become two points that are not at the same time for the > other person and so the points no longer are a length (which is an > interval of space) but are now an interval of space and an interval of > time. So a purely spatial interval becomes a space and time interval. > So for example today now here a gun goes off and in Washington DC at > the same time a gun goes off. That now becomes today here and now a > gun goes off and then latter in Washington DC a gun goes off. > Actually, it was a man named Minkowski who sort of summarized Einstein > this way. > > It does not mean that time and space are really the same thing > however. Locally, for any given observer they are very different. > > Also, time is related to material causality, so you can have a circle > in space but not one in time. The universe may be spherical spatially > but not in time because it causes problems with causality. (However, > you can imagine a universe that repeats and in a sense that is a > circle in time! Its just that if you are to preserve causality you > describe it as a line that just repeats. How subtle the ideas of > physics!) Relativity does preserve the ability to have material > causality since no signal can go "faster than light" meaning that > nothing here can cause something over there before light could reach > it. If such an effect were discovered then the center of relativity > theory would be destroyed. It is all based on that assumption. > Therefore the future need not be determined in relativity. Causality > can exist but its effect must be local. There can be no instantaneous > action at a distance that is all. I can affect a star 4.5 light years > away from the earth relative to the earth only 4.5 years from now > relative to earth. > > (In the old theory of Newton the idea that everything was determined > was also there. But that does not mean that there is no material > cause. It just meant that if you know all of the causes and you know > where everything is and how fast it is going at one point in time then > you can predict the future forever. The same is true in relativity but > what is interesting is that it is not true in quantum mechanics. That > theory is non deterministic and only allows you to predict > probabilities. Also remember that material cause is not the cause of > the universe. It is only cause in the universe. ) > > What is interesting is that if I travel really fast it turns out that > relative to me I can get to that star in as short a time as I want. I > can get there in say 10 min and affect it - meaning cause something > there....the catch is...I must measure that 10 minutes on my wrist > watch. But someone on earth watching me would see me traveling for 4.5 > years and would watch my watch moving very slowly for those 10 > minutes! > > So the fact that it takes light 4.5 years relative to the earth to > reach some star and the fact that nothing can go faster than light > does NOT mean that I must take 4.5 years relative to my wrist watch to > get there. In fact I can get there as fast as I want! Its just that > everyone home will have aged a little more than me. > > Relativity and quantum mechanics are very interesting theories. There > are deep philosophical reasons why they seem so strange. These reasons > are because we are so confused about what "to be" means. We think it > means to be a thing in the universe but that is not really it. Numbers > are and they are not things. And even the universe is not best > described as a bunch of things. There is for example color which > exists but cannot be described just by using the idea of things moving > around in space. So you end up back in philosophy and perhaps the best > way to describe everything is that it is the experience we are having > together. Describing that experience is where science comes in. > Understanding what it means however... well... its just not > scientific.... its philosophical... and when you start to become aware > of the meaning of the universe certain experiences start to happen in > you that are not describable within the current theories. That's why > people who are only aware of science thing that the people who are not > only aware of science are such raving lunatics. > > It is also why there is interest in this group. The term "Minds eye" > is a very old term that refers to the experience of the meaning of the > universe. The interesting thing about the charter of this group is > that it purports to discuss these things rationally so you are at the > meeting of science and the rest of the culture. > > On Aug 25, 8:47 pm, Michael Berkovits <[email protected]> wrote: > > > I actually disagree with your interpretation of the continuum (though > > of course I'd be happy to hear more thoughts). This is what the link > > said: > > > "This new reality was that space and time, as physical constructs, > > have to be combined into a new mathematical/physical entity called > > 'space-time', because the equations of relativity show that both the > > space and time coordinates of any event must get mixed together by the > > mathematics, in order to accurately describe what we see. Because > > space consists of 3 dimensions, and time is 1-dimensional, space-time > > must, therefore, be a 4-dimensional object. It is believed to be a > > 'continuum' because so far as we know, there are no missing points in > > space or instants in time, and both can be subdivided without any > > apparent limit in size or duration. So, physicists now routinely > > consider our world to be embedded in this 4-dimensional Space-Time > > continuum, and all events, places, moments in history, actions and so > > on are described in terms of their location in Space-Time." > > > A continuum doesn't have to be infinite. Dictionary.com defines a > > continuum as "a continuous extent, series, or whole." It adds the > > mathematical definition of "a set of elements such that between any > > two of them there is a third element." Think of a line segment. It's > > finite, but continuous - between any two points on the line, there's > > another point. > > > When the speaker says "there are no missing points in space or > > instants in time," he is referring to the current set of space-time. > > Doesn't mean that the set can't expand. Indeed, the universe is > > expanding, thereby increasing the total amount of space in existence > > (and hence, the total amount of space-time in existence, as space is > > an aspect of space-time). > > > If you could spell out more clearly what, from science, suggests that > > the future has already happened, then I would be curious and grateful > > to > > ... > > read more ยป --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups ""Minds Eye"" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/minds-eye?hl=en -~----------~----~----~----~------~----~------~--~---
