Just a fine point MB, but I don't think you can equate a vacuum with nothing. A vacuum is a vacuum, the absence of atmosphere, but clearly matter can exist in a vacuum as can light waves and radio waves. But nothing is just that. Nothing. No thing. The absence of everything.
Regards the big bang (which is also a tv sitcom I enjoy), if that was the singularity from which all we consider to be in our universe emerged, within what did that singularity exist prior to going bang. Nor do I think my statements preclude the usefulness of anything we have discovered regardless the errors we assume about it. We are a very resourceful species and made much of what we have discovered so far, right wrong or indifferent. I just hope we mature out of adolescence before we discover something we could really hurt ourselves with. /e On Aug 26, 11:09 am, Michael Berkovits <[email protected]> wrote: > > 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. > > I think the "universe" refers to the space-time continuum. Outside the > universe is a vacuum - just as before the universe emerged from the > Big Bang, there was a vacuum, i.e., nothing. > > As far as we know from the current state of scientific knowledge, the > universe is expanding in the sense that it began from a single point, > and that the things furthest away from us appear to be getting even > further away. The fact that it doesn't make linguistic sense to > postulate "boundaries" to the universe is (at least according to > modern physics) more a function of deficiencies in our language and > understanding than it is a knock on the theory that the universe is > expanding. > > While I can't pretend to intuitively understand what it would mean for > the universe to simultaneously be "all that there is" yet to be able > to expand into something else, we can still talk about it > analogically. "Outside" the universe is a vacuum, and the reason the > universe is able to expand is because it is made of real "stuff," > i.e., space-time. The picture that conjures is of a giant fabric > expanding into infinite blackness. Clearly, this picture is not > "accurate," any more than it was accurate to think of electrons going > around the nucleus as shiny balls of energy smoothly orbiting in > perfect circles. But it's a model that presumably has some truth to > it, just as the electron orbital model does. By not being perfectly > accurate, it leaves lots of stuff out, but that doesn't make it > useless. Newtonian physics was quite useful for 300 years before being > updated. Unlike some other things in science, it seems that Newtonian > physics needed to be modified rather than thrown out entirely - > hopefully, the same is true for the well-established concepts in > modern physics. > > On Aug 26, 9:40 am, gruff <[email protected]> wrote: > > > 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. > > ... > > read more ยป --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups ""Minds Eye"" group. 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