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Warp wrote:
> However, I don't understand why GR would predict a curved universe
> where each geodesic line is closed. What would cause it? Certainly not
> the mass in the universe. I don't think it would be even nearly enough.
Last I saw, estimates were that we're within experimental uncertainty
about whether we're within our own Schwartzchild radius. I.e., depending
on what 'dark energy' does, and just how much 'dark matter' is out
there, the universe may be flat, positively curved, or negatively curved.
> (Because if it was caused by mass, it would mean that the entire universe
> is actually inside its own Schwarzschild radius, which is clearly not the
> case.)
Not sure why you would think that. If there's enough mass to eventually
collapse the universe back to the "big crunch", then by definition we're
in a "black hole" out of which no light can escape. It's just a really
big one, hundreds of billions of light years in diameter. :-)
I'm not sure the singularity math works from the inside, either.
> I don't find any kind of logic in that. Why would there be a "similar",
> "parallel" version of anything if you travel far enough? It doesn't make
> any logical sense.
Probably in the "inifinite monkeys type shakespear" kind of way.
--
Darren New / San Diego, CA, USA (PST)
It's not feature creep if you put it
at the end and adjust the release date.
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stbenge wrote:
> nemesis wrote:
>>
>> perhaps our own Universe is nothing but a side-effect of something
>> bigger...
>
> Some of the new theories point an explanation regarding this. According
> to the theories, only certain particles can pass between dimensions, or
> branes. Two of these particles are tachyons and gravitons (not sure if
> the latter have been identified yet though).
And Dust!
--
Darren New / San Diego, CA, USA (PST)
It's not feature creep if you put it
at the end and adjust the release date.
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In article <4778f2c3@news.povray.org>, war### [at] tag povrayorg says...
> Tim Attwood <tim### [at] comcastnet> wrote:
> > > Schwarzchild radius is not dependent on density, only on the amount
of
> > > mass.
>
> > That's only true for black holes. For normal matter it varies by densit
y,
>
> "The Schwarzschild radius (sometimes historically referred to as the
> gravitational radius) is a characteristic radius associated with every
> mass. It is the radius for a given mass where, if that mass could be
> compressed to fit within that radius, no known force or degeneracy
> pressure could stop it from continuing to collapse into a
> gravitational singularity."
>
> "The Schwarzschild radius is proportional to the mass, with a
> proportionality constant involving the gravitational constant and the
> speed of light."
>
> http://en.wikipedia.org/wiki/Schwarzschild_radius
>
> No mention of density anywhere, only of mass. The Schwarzschild radius
> of a mass can be calculated directly as the mass multiplied by a
> *constant* (which is 2*G/c^2). Volume doesn't appear anywhere in the form
ula.
>
> > if the mass of the universe is infinite it falls inside
> > it's Schwarzschild radius, since rs = 2Gm/c^2 ... and infinity divide
d by
> > a large number is still infinity.
>
> Which is a rather definite proof that there's a finite amount of mass
> in the universe.
>
> > > I call this the shakespeare-monkey fallacy.
>
> > It's not a fallacy, it's a paradox, there's a difference. It's not poss
ible
> > to predict random events, but it's still possible to know that they wil
l
> > occur. For example if you use a simple coin toss, and toss the coin
> > forever, the distribution will be 50/50, so you can say with 100%
> > confidence that sometime in the future there will be another "heads",
> > yet at the same time you don't know at all if the next toss will be
> > a "heads".
>
> It's a fallacy. An infinite amount of data, even if all values have the
> same "chance" of appearing in the data, does not automatically mean that
> every possible pattern appears.
>
Snort. But you are proving his point. In any infinite universe in which
"every" combination possible doesn't exist, then some combinations
**must** be identical. Worse, if you have infinite mass, but finite
numbers of ways it can combine, then there **must** be instances where
some large number of duplications exist. The only question is, how
limited is the set of possible configurations, and how infinite is the
range of places they can take place in. Obviously, the odds of getting
an identical sequence from a set that *only* contains 50 combinations,
given an infinite number of tries, is much more likely than one that
requires 500 trillion identical combinations, even with an infinite
number "tests" (or in this case, places where such might happen). While
its true that any *single* such sequence/set of combinations are no more
likely than any other, it is simply not possible to have an infinite
number of such combinations, and not have duplicates. The only
"fallacy" is if you pointed at this planet, and said that some place
there **must be** one just like it. We could be the one single set of
very large number of combinations of matter that *wasn't* duplicated an
infinite number of times, just as there could be some subset of cases
that have "never" happened. But its just not mathematically sound to
imply that there would *never* be such duplicated. That just isn't
possible, unless you also have an infinite number of ways that it "can
be" combined. Simple economies of scale imply that the smaller the
object you are describing, the less "possible" it is for it not to exist
some place else, in such a universe.
> The proof is rather simple: For example, the ordered set of natural
> numbers is an infinite set where each value has an equal "chance" of
> appearing, yet eg. the pattern "2 1" never appears.
>
Again, only if you are looking at it in terms of *each* number being its
own unique thing. However, if you presume that the "set" of possible
forms was 0-9, and that there is simply an infinite number of
combinations, then obviously you *do* get "2 1", in 21, 210, 211, 212,
etc. Your example assumes an infinite number of unique "combinations",
in an infinite set of possible combinations. That is true. If you found
an identical Earth, you might not find one that is both identical *and*
in a solar system with the same number of other planets, comets,
asteroids, constellations, etc. Something **would** be different. But
that doesn't mean that the "object" of your examination "isn't" nearly
identical, save for those things that are not directly "part" of it,
which make it different, any more than you can claim that the sequence
21 doesn't happen in 213, just because there happens to be a 3 in it.
Or, to put it in terms that one cartoon did, just because an infinite
number of monkeys, typing randomly or otherwise, on an infinite number
of type writers, might never reproduce Shakespeare, that doesn't mean
they wouldn't reproduce Terry Pratchett instead. Your setting an
artificial standard from the beginning, implying that one improbable
solution doesn't have to happen. Its way different than saying that
**no** improbable solution will ever happen.
--
void main () {
if version = "Vista" {
call slow_by_half();
call DRM_everything();
}
call functional_code();
}
else
call crash_windows();
}
<A HREF='http://www.daz3d.com/index.php?refid=16130551'>Get 3D Models,
3D Content, and 3D Software at DAZ3D!</A>
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stbenge wrote:
>
> Over that? Nah!
>
It's just the "revving the engine" part.....
--Sherry Shaw
--
#macro T(E,N)sphere{x,.4rotate z*E*60translate y*N pigment{wrinkles scale
.3}finish{ambient 1}}#end#local I=0;#while(I<5)T(I,1)T(1-I,-1)#local I=I+
1;#end camera{location-5*z}plane{z,37 pigment{granite color_map{[.7rgb 0]
[1rgb 1]}}finish{ambient 2}}// TenMoons
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Patrick Elliott <sel### [at] rraznet> wrote:
> Snort. But you are proving his point. In any infinite universe in which
> "every" combination possible doesn't exist, then some combinations
> **must** be identical.
Well, if we have an infinite amount of singularities, I wouldn't call
them "parallel universes", even though they are all identical to each
other (except for mass, rotation and electric charge).
Also, if we have, for example, an infinite amount of evenly-distributed
hydrogen (or dark matter, or dark energy, or anything) I also wouldn't call
that "parallel universes".
> Worse, if you have infinite mass, but finite
> numbers of ways it can combine, then there **must** be instances where
> some large number of duplications exist.
Duplication can be trivial. It's enough to have an infinite amount of
evenly-distributed mass (or just energy).
But anyways, as pointed out, if there was an infinite amount of mass
in the Universe, the Schwarzschild radius of the Universe would also
be infinite, which would mean that the entire Universe is a black hole,
which is clearly not the case. (Black holes have all kinds of funny
features which clearly don't happen in this universe. For example, all
geodesics would point to the singularity and there's no way to avoid
everything going there. Even timelines go to the singularity, so just
advancing in time makes everything go to the singularity.)
> Or, to put it in terms that one cartoon did, just because an infinite
> number of monkeys, typing randomly or otherwise, on an infinite number
> of type writers, might never reproduce Shakespeare, that doesn't mean
> they wouldn't reproduce Terry Pratchett instead. Your setting an
> artificial standard from the beginning, implying that one improbable
> solution doesn't have to happen. Its way different than saying that
> **no** improbable solution will ever happen.
I have never said that it cannot happen. I just oppose the claim that
something will inevitably happen.
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Last I saw, estimates were that we're within experimental uncertainty
> about whether we're within our own Schwartzchild radius.
If GR is right, then the universe would look a lot different if we were
inside that radius. The GR equations have funny properties inside this
radius. For instance, all geodesics, including timelines, go to the
singularity, and there's no escaping it. Even if you try to keep away
from the singularity you just can't, because advancing in time is equal
to advancing towards the singularity.
As far as I know, the universe is *expanding*, not going towards a single
point.
> > (Because if it was caused by mass, it would mean that the entire universe
> > is actually inside its own Schwarzschild radius, which is clearly not the
> > case.)
> Not sure why you would think that. If there's enough mass to eventually
> collapse the universe back to the "big crunch", then by definition we're
> in a "black hole" out of which no light can escape. It's just a really
> big one, hundreds of billions of light years in diameter. :-)
A star is not a black hole even during its own collapse. Not until it
gets inside its own Schwarzschild radius. Collapse does not mean that
the thing which collapses is a black hole.
> > I don't find any kind of logic in that. Why would there be a "similar",
> > "parallel" version of anything if you travel far enough? It doesn't make
> > any logical sense.
> Probably in the "inifinite monkeys type shakespear" kind of way.
Which is a fallacy.
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > If you were at the center of the galaxy you wouldn't be looking at the
> > sky. I think you would be infinitely small.
> I'm not sure anyone is sure what happens in the middle of a black hole.
> If "you" were in a position to see, you could certainly see the sky. The
> sky couldn't see you, mind.
It's true that nobody dares to even guess what is happening inside the
event horizon of a black hole. However, if GR is right, everything inside
the event horizon inevitably goes to the singularity and there just isn't
escaping it. You just can't keep away from it no matter what you try.
> Surely you're not asking seriously? A sphere is a 2D finite surface with
> no border.
The sphere is its own border.
--
- Warp
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Warp wrote:
> which is clearly not the case. (Black holes have all kinds of funny
> features which clearly don't happen in this universe. For example, all
> geodesics would point to the singularity and there's no way to avoid
> everything going there. Even timelines go to the singularity, so just
> advancing in time makes everything go to the singularity.)
I think the problem with trying to say what happens in a singularity is
that we have only mathematical models of what happens. The reason
they're even *called* a "singularity" is that the mathematical models
break down there, like dividing by zero.
Saying we're not inside a black hole implies we know what happens inside
a black hole. Plus, a sufficiently large black hole can have a
surprising amount of livable space inside.
How do you know everything doesn't go to a singularity in the future?
That would be the "big crunch" theory, which I understand scientists
believe is true if the universe contains enough mass to be finite in size.
--
Darren New / San Diego, CA, USA (PST)
It's not feature creep if you put it
at the end and adjust the release date.
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Warp wrote:
> As far as I know, the universe is *expanding*, not going towards a single
> point.
If there's enough mass, then eventually gravity will pull everything
into a "single point", just like everything came from a single point
during the big bang. (At least, that's my lay understanding.)
>> Not sure why you would think that. If there's enough mass to eventually
>> collapse the universe back to the "big crunch", then by definition we're
>> in a "black hole" out of which no light can escape. It's just a really
>> big one, hundreds of billions of light years in diameter. :-)
>
> A star is not a black hole even during its own collapse. Not until it
> gets inside its own Schwarzschild radius. Collapse does not mean that
> the thing which collapses is a black hole.
I'm not sure "Schwarzschild radius" makes sense in the context of "all
of space-time". I.e., what does "radius of the universe" mean?
>>> I don't find any kind of logic in that. Why would there be a "similar",
>>> "parallel" version of anything if you travel far enough? It doesn't make
>>> any logical sense.
>
>> Probably in the "inifinite monkeys type shakespear" kind of way.
>
> Which is a fallacy.
I didn't say it was right. :-) But yah, I guess if you strictly mean
"in any logical sense", it isn't logical.
--
Darren New / San Diego, CA, USA (PST)
It's not feature creep if you put it
at the end and adjust the release date.
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> If you were at the center of the galaxy you wouldn't be looking at the
>>> sky. I think you would be infinitely small.
>
>> I'm not sure anyone is sure what happens in the middle of a black hole.
>> If "you" were in a position to see, you could certainly see the sky. The
>> sky couldn't see you, mind.
>
> It's true that nobody dares to even guess what is happening inside the
> event horizon of a black hole.
Not true. They just won't guess what happens at the singularity. It's
called a singularity because the math breaks down there.
Calculate the gravitational curvature at the Schwartzchild radius for a
galaxy-sized black hole. It's not that great. You likely wouldn't even
notice you'd crossed any sort of boundary. (At least, that's what I've
read. I am not sure how to do the math myself.)
> However, if GR is right, everything inside
> the event horizon inevitably goes to the singularity and there just isn't
> escaping it. You just can't keep away from it no matter what you try.
Sure. Let me know when you figure out how to escape the universe. :-)
>> Surely you're not asking seriously? A sphere is a 2D finite surface with
>> no border.
>
> The sphere is its own border.
No, the sphere is a border for a ball, not a sphere.
(Sorry if that "surely" comment sounded insulting. It just surprised me
that anyone with a background in technology and graphics wouldn't be
familiar with this.)
Take, as an alternate example, a video game like "asteroids", where the
stuff that goes off the top of the screen comes on the bottom, and the
sides are connected. This is geometrically equivalent to a torus. There
are no boundaries for the spaceship to run into, but the space is still
finite. It is postulated that the universe could be like that.
You can even have a space where the sides are boundaries but the top and
bottom are connected (forming a cylinder), meaning finite space but only
bounded in some places and not others.
--
Darren New / San Diego, CA, USA (PST)
It's not feature creep if you put it
at the end and adjust the release date.
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