What's with all the useless universes?

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One analogy often used to describe this edgeless universe is the surface of a balloon. An ant on such a surface can walk in any direction and it would look like the surface was “unbounded” — that is, the ant might come back to where it started but there would be no end to the journey. So even though the surface of a balloon is a finite number of square units, there’s no edge to it, no boundary (since you can go forever in any one direction). In addition, there’s no “center,” so there’s no preferred point on the balloon’s spherical surface. Like our universe.
 
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Mosquitoes, ticks etc are a significant food source for other creatures that eat them.

Creatures that eat mosquitoes or their larvae include birds, fish, frogs, and dragonflies.
 
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I do, Earth’s surface is unbounded (has no edge), but still finite since it is a sphere.

However the Universe itself is quite different and the distances there are way beyond anything we can imagine.

Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite. This is something already mentioned above, where I mentioned the big “IF” of the unobservable space, where no one knows how much there is of it, or what it contains.

So the Universe could be unbounded, and yet still be finite in size, because if it is both unbounded and infinite God would never finish destroying it.
 
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neophyte said:
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Barnesy:
The universe is probably infinite in distance. Remember the 4% error!! But not in time. Read about entropy!!
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Ummm… no. The known universe cannot be infinite in size, because that would require it to be infinite in age (given that it’s expanding from size = 0 starting less than 14 bilion years ago).

Also, you keep forgetting to put 0. in front of 4%.
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No, its not expanding out into a big thing from a smaller thing. When people say that it was the size of a grapefruit or the size of a basketball or millions of miles in diameter they are talking about the observable universe. Lots of people make that mistake! They think it started out small and got big and that took lots of time but there hasn’t been infinite amount of time so it cant be infinite in size. Whew!

Lots of people when they write about the size leave out the observable bit and they shouldn’t because thats what they mean. But you should always put it in if they leave it out. This person puts it in.

Here are some fun milestones, going back in time, that you may appreciate:
  • The diameter of the Milky Way is 100,000 light years; the observable Universe had this as its radius when it was approximately 3 years old.
  • When the Universe was one year old, it was much hotter and denser than it is now. The mean temperature of the Universe was more than 2 million Kelvin.
  • When the Universe was one second old, it was too hot to form stable nuclei; protons and neutrons were in a sea of hot plasma. Also, the entire observable Universe would have a radius that, if we drew it around the Sun today, would enclose just the seven nearest star systems, with the farthest being Ross 154.
  • The Universe was once just the radius of the Earth-to-the-Sun, which happened when the Universe was about a trillionth (10^–12) of a second old. The expansion rate of the Universe back then was 10^29 times what it is today.
Thats from here How big was the Universe at the moment of its creation? | by Ethan Siegel | Starts With A Bang! | Medium

See when he says observable all the time? That what youve got to do. Put it in all the time and then it makes better sense. Because it didnt have a size zero. And thanks for the 0.04%! I must have made a mistake.
 
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John10 said:
I do, Earth’s surface is unbounded (has no edge), but still finite since it is a sphere.

However the Universe itself is quite different and the distances there are way beyond anything we can imagine.

Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite. This is something already mentioned above, where I mentioned the big “IF” of the unobservable space, where no one knows how much there is of it, or what it contains.

So the Universe could be unbounded, and yet still be finite in size, because if it is both unbounded and infinite God would never finish destroying it.
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You did it again John. You said that god couldnt destroy something infinite!! Because it would take too much time. Thats like saying it would take him a long time to destroy something very very big which would be silly. If god made the universe infinite he did it. And if he wants to destroy it he can. Maybe you think that god takes time to do things which is wrong.
 
The issue is with regard to the Universe specifically, which is very different from an abstract concept such as numbers, an infinite Universe has no size by definition. It is important to clarify the terms we use, because although similar they are not the same.
 
John10 said:
The issue is with regard to the Universe specifically, which is very different from an abstract concept such as numbers, an infinite Universe has no size by definition. It is important to clarify the terms we use, because although similar they are not the same.
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But you said god couldnt destroy the universe if it was infinite in size because he wouldnt have enough time. But god doesnt live where we live inside time. So i dont understand what you mean.
 
John10 said:
It’s not about time Barnesy, it’s about logical consistency, if the Universe is infinite it has no size, so there is no way to destroy it.

We know God created the Universe and will also eventually destroy it, so it cannot be infinite, but it can certainly be extremely big.

See: http://www.godandscience.org/apologetics/universe_too_large.html
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Maybe god didnt create it. Because there wasnt any stuff for him to use. Before he created it there was no size to it. Maybe youd say that it was a logical consistency that he couldnt do it. But guess what?? He did. Out of nothing!
 
Barnesy said:
Lots of people when they write about the size leave out the observable bit and they shouldn’t because thats what they mean. But you should always put it in if they leave it out. This person puts it in.
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You seem to be using that as a rationalisation that allows you to propose wildly speculative ideas, for which you have no evidence, as if they were fact.

One last time: something can be both bounded and infinite, and God is able to destroy the universe no matter how large it is.
 
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neophyte said:
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Barnesy:
Lots of people when they write about the size leave out the observable bit and they shouldn’t because thats what they mean. But you should always put it in if they leave it out. This person puts it in.
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You seem to be using that as a rationalisation that allows you to propose wildly speculative ideas, for which you have no evidence, as if they were fact.

One last time: something can be both bounded and infinite, and God is able to destroy the universe no matter how large it is.
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But what i said shows that the universe didnt start small and grow bigger like you said. The observable universe started small and grew bigger!! The universe and the observable universe arent the same. The observable universe was very small when the big bang happened and is now very large. But if the universe is infinite then it didnt start small. You cant grow from small to infinite. To find out how fast it was expanding youd have to divide the time by infinity and that doesnt work.

But yeah i hope john read what you said about God being able to destroy it even if it is infinite.
 
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I know He did, that proves that He is omnipotent, however as I said before that does not mean He will do self-contradictory things, because those do not make sense.

God can destroy the Universe not matter how big it is, however He cannot destroy an infinite Universe because by it’s own definition that Universe has no size, so you start to get into a self-contradictory dilemma.

So because we know God created it and will eventually destroy it, it gives good reasons to believe it is not infinite, although it could be extremely big, beyond our imagination.

Adding to the above, as I have stated already and have not seen anything to disprove it, let’s not forget

“Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite”. We are only able to see a very small portion of the Universe, that is something almost everybody agrees on.
 
Gee i dont know enough to explain it all. But i can show you people that know more than we do. Like this man.

The Universe was not concentrated into a point at the time of the Big Bang. But the observable Universe was concentrated into a point.

medium.com

How big was the Universe at the moment of its creation?

Everything in the Universe today was compressed into a tiny volume. But how small was it?
medium.com medium.com

And this man as well.

If the universe is infinite, it has always been infinite. At the Big Bang, it was infinitely dense. Since then it has just been getting less dense as space has expanded.

Khan Academy

www.khanacademy.org www.khanacademy.org
 
John10 said:
I know He did, that proves that He is omnipotent, however as I said before that does not mean He will do self-contradictory things, because those do not make sense.

God can destroy the Universe not matter how big it is, however He cannot destroy an infinite Universe because by it’s own definition that Universe has no size, so you start to get into a self-contradictory dilemma.

So because we know God created it and will eventually destroy it, it gives good reasons to believe it is not infinite, although it could be extremely big, beyond our imagination.

Adding to the above, as I have stated already and have not seen anything to disprove it, let’s not forget

“Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite”. We are only able to see a very small portion of the Universe, that is something almost everybody agrees on.
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You said things that are contdadictory too. You said God created the universe. And there was nothing he could have used. Nothing has no size and he created something. So even if the universe has no size he can destroy it. Your argument is wrong and it also makes no sense. Thank you.
 
vz71 said:
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Barnesy:
You said God created the universe. And there was nothing he could have used.
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God created everything from nothing.
I see nothing contradictory in that.
It is just basic theology.
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Thats right. And nothing is even smaller than an infinitely small some thing. So he can create some thing from less than an infinitely small thing but you say he cant destroy something infinitely big. I dont think thats theology at all. God can create something from nothing so im sure he can create an infinitely large universe. Thats not a contradictory thing. So saying that god created something and he cant destroy it is silly.
 
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Flatness means that two parallel lines on a flat 2d object never meet and never get farther apart from each other. Two lines can also never meet on a hyperbolic surface (think of a saddle for horseback riding) but after a single point on each line that is as close as the lines ever get, they always get farther apart after that. Two parallel lines on a sphere, while seeming to be parallel after they travel an infinitesimal distance, always end up meeting at the poles. All of the lines with intersect the poles are also known as great circles. Lines of longitude are all great circles, as is the equator. There can be an infinite number of pole pairs and an infinite number of sets of great circles on any given sphere.

A flat 2d surface that is infinite in one direction and finite in the direction perpendicular to that can be rolled up into a cylinder in which the two lines travel around the short direction to make two circles, or travel around the cylinder in two parallel spirals forever and ever, or travel parallel to each other in a direction parallel to the infinite direction.

A cone is another ‘flat’ shape, or more properly, a shape which can be made by cutting up a flat sheet and taping it together. Think of a disk with a section missing. If you take a paper cone such as one suitable for a sno-cone and cut from the edge down to the point, you will end up with a disk that has a missing section. Parallel lines will behave similarly to the infinite spirals on a cylinder except that after coming close to the point they will cross both their parallel partner and themselves at points. The behavior of the parallel lines will be similar to the behavior of a ribbon or a piece of tape attached to a cylinder or a cone.

When one is dealing with two infinitesimally close parallel lines, lines that are traveling as close to straight as they can be made to be, one is said to be traveling along a geodesic.

A flat 2d metric can always be reduced to a square 2 by 2 ‘indicator’ (I forget the exact term) matrix such as the following:

(1, 0)
(0, 1)

A flat universe with one time dimension and 3 space dimensions can always be reduced to either a 1 with 3 negative ones or a -1 with 3 positive ones along the trace of the ‘indicator’ matrix, such as the following:

(1, 0, 0, 0)
(0, -1, 0, 0)
(0, 0, -1, 0)
(0, 0, 0, -1)

or

(-1, 0, 0, 0)
(0, 1, 0, 0)
(0, 0, 1, 0)
(0, 0, 0, 1)

Here is a flat space-time metric in Cartesian coordinates which would approximate an empty vacuum in our universe which was far away from any mass:

c^2 dt^2 - dx^2 - dy^2- dz^2

where c is the speed of light, dt is the time infinitesimal, and dx, dy and dz are the infinitesimals for the x, y, and z directions respectively.

Whether you ultimately end up with a 1 and three -1s or a -1 and three 1s along the trace depends upon which convention you favor for the metric. Once you pick a convention, you have to stick with it throughout your calculations. After that, you cannot change conventions (or horses) in midstream.

In a flat space-time such as ours, the product of the trace (in this case, equal to the determinant) of the ‘indicator’ matrix must always turn out to be -1.
 
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