Logically why the universe cannot be infinite in size.

[donnydarkoIRL]

I don't really no much about it. Sometime id like to get one of those dream interpretation books, but i don't have the inclination at the moment.

[Bomp]

The big bang theory is incompatible with an infinte universe. It is widely accepted nowdays that the universe is not infinite, it was discredited a long time ago by a logical thought experiment.

It was assumed some time ago that the universe was infinite, this was because if it wasn't infinite, then it would collapse in on itself due to gravity. So it was postulated that the universe was infinite (and also almost uniform in distribution to prevent to much variance in mass at different regions, which would also cause many smaller collapses).

However, IF the universe was infinte in size AND unifrom, then the sky as we look at it would be INFINITELY bright. The explanation for this is that if you consider imaginary spherical shells of all different sizes with earth at the centre of them, and the surface area of each of these shells is determined by 4*pi*radius(squared) (radius being the unifrom distance of the shell fromthe earth) : Then, since the universe must be uniform, then the amount of stars on each shell must be proportional to
the distance from earth (i.e. the shells radius) squared.

Following on from this, when you take into account the physical relationship that the intensity of radiation decreases inversely proportional to the distance from the source squared(i.e. once again the radius of the shell squared), then it must be concluded that the amount of radiation coming from each shell must be equal, no matter how far away the shell is. Since the amount of radiation coming from each shell is finite, and that there are an infinite number of shells, then the radiation wacking the earth every second would be infinte.


The big bang theory originally came about to counter this by trying to explain the fact the universe is expanding, and not collapsing in on itself as it would if it were finite.

However, since then, even crazier shit have been hypothesized (but not proved) such as anti-gravity to take into account the expanding universe.

[brucelee]

the question is how finite is the universe?where does it stop? if it is finite then it is improper to call it "universe".

[Punisher136]

Think of the universe as a bunch of marbles (galaxies). Those marbles can move in any direction and there's almost no limit to where they can move. Because of their existance tho, space has to curve around them or the physics aspect would be off and it would be unbearable pressure making life or the moving of anything nearly impossible. It can expand and contract with the movement of galaxies but at any given time it does have a definite size that is too large to be measured by humans. Like I said before, this edge wouldn't physical exist but it is more or less a spot of high gravity where you can't move any further.

[Bomp]

Yeah, there's loads of crazy shit when you look into general relativity and all that. Truth is, the universe doesn't work as simply as we see everyday things happen, when you take into account giant masses and the invariance of the speed of light. Even if the universe is finite, you would never actually be able reach the 'edge' of it, it is thought if you set out in a 'straight' line and kept going indefinitely, you could end up where you started due to curved space and all that.

[Punisher136]

Yeah, there's loads of crazy shit when you look into general relativity and all that. Truth is, the universe doesn't work as simply as we see everyday things happen, when you take into account giant masses and the invariance of the speed of light. Even if the universe is finite, you would never actually be able reach the 'edge' of it, it is thought if you set out in a 'straight' line and kept going indefinitely, you could end up where you started due to curved space and all that.

I'm not a fan of string theory, but I believe einstein was on the right track when he had relativity and most of the space-"time" stuff.

[SlimTrae]

Ok this a problem for the more curious amongst you Punisher etc but it is always said that the universe is infinite in size.

I however disagree with this as being scientifically impossible and I'm wondering who agrees with me?

If we believe the scientific model that the universe started from a Big Bang, then literally at the beginnning there was nothing. Now when the universe exploded into existence it began to expand according to science.

Now here's my problem. If something starts from somewhere, i.e has a beginning it can never be infinite in size or any other way, just not possible.

You cannot expand yourself to infinity because you'd never get there. By expanding you'll always be bigger than you were before but not as big as you are soon going to be, kind of like Bigaru or Boxing Gorilla :P


Anyways imagine it with numbers, if you start at 1 you cannot ever get to infinity by adding numbers because there will always be a higher number out there.

If the universe started from a tiny fixed point and has expanded ever since it cannot be infinite in size. If you could trace it back 15 billion or so years to the beginning (according to science) and it would be so small you could hold it on an eye of a needle then how can it be infinite in size now?

Not possible, it's just very very very very fucking big but not infinite.




Thankyou.

BUMP! Not sure if this poster is still here, But I dig the topic!

Where I would question is this partial statement: If something starts from somewhere, i.e has a beginning it can never be infinite in size

I disagree. Having a beginning isn't synonymous with having an ending. So for those who feel the universe will one day tear/rip apart or contract after expanding--they could say there is no Infinite universe. Simply because they hypothesize an ending.

However if the universe expands from any point (and never cease in motion) that right there IMO is a pretty good definition of infinity. In other words it isnt the size of the univere as much as its activity: its moving in all directions & accelerating at that!

Infinity: a number greater than any assignable quantity or countable number.

Since we have no system of assigning an end goal, point or fixture of our existence in the universe contained in something we call space. Space itself is infinite and will continue its journey of creating a place where any existing form of matter no matter how intelligent it becomes--will never reach that fixture- cause it is ever expanding!

Its just another Bilbo argument. Bilbo, you have no way of knowing how large the universe is so your suggestion is faulty.

I realise I have no way of knowing how big it is but logically it cannot be infinite can it?

If it started from a single point, and both science and religion agree that it did then how can it be infinite?

If you start at 1 and begin counting you will NEVER get to infinity will you. Why is this any different? You start from an atom (actually smaller) sized but rapidly expanding universe, it's always getting bigger.

If it's getting bigger it CANNOT be infinite.

Simple logic my Korean friend.

Againm my question deals specifically with certain sentences and not the entire post, I quote: If you start at 1 and begin counting you will NEVER get to infinity will you.

I see the same thing from a different perspective. I would word it like this: If you start at 1 and begin counting you will NEVER get to infinity because infinity has no end point.


BUMP! Not sure if this poster is still here, But I dig the topic!

[SlimTrae]

The one problem I see with your theory is that you are saying that infinite is an individual number ie 5737027593. From what I have learned in my math classes is that infinite is not an individual number, it is just a way of saying a number larger than what we can imagine. Like someone already said there is always a number larger than whatever number you can come up with.

At least mathematically speaking.

That's how I see it!

The edge isn't physical but the gravity around that area would prevent you from moving any further in that direction. Pun

I see.


Really, I guess it doesn't make a difference. We are not capable of getting anywhere close to the edge of the universe and reporting back to anyone so it is infinite as far as humans are concerned.

If Pi is infinite then I'd bet that the universe is as well. What good is an infinite number in a finite universe?

The edge isn't physical but the gravity around that area would prevent you from moving any further in that direction.<<--How I think of the edge.

The one problem I see with your theory is that you are saying that infinite is an individual number ie 5737027593. From what I have learned in my math classes is that infinite is not an individual number, it is just a way of saying a number larger than what we can imagine. Like someone already said there is always a number larger than whatever number you can come up with.

At least mathematically speaking.

Here's the thing with numbers, their only purpose is to help us understand the world around us. Let's say 100 was the biggest number we'd need to use to measure anything. We could add 1 to that to make number 101 but that number would have no use other than being a number. The same thing goes for the really small numbers. After so many places right to the decimal, there's no value in that number. Like .00000000000000000000000001 may have a purpose somewhere in our field but several places down the line its value in the real world realistically becomes 0 as nothing that small currently exists or is measureable.

I can't say I define numbers (symbols to define them) as some would say; an invention. IMO it is an internal system that allows anything with consciousness to account for its surroundings.
My example is my girlfriends cat. that fur ball IMO has no clue of math, but it knew how to figure out some of her kittens were missing. meaning it can comprehend amassing and the opposite-losing what she had.

The marvel of the Arabic numeral system IMO proves it is not an invention. Now Roman numeral system was an invention that proved faulty.
To add, subtract, computational, to divide, to multiply, summarize fractions are not inventions rather a means in which our brains reason & or perceive as a result of our eternal creator endowing us with the ability to account to amass.
It is a skill acquired depending on the civilization in question.
Our numeral system with placements using just the symbols of 0,1,2,3,4,5,6,7,8,9 allows us to determine a dosage of medicine or how to send a satelite into space is beyond symbols, into something I know blows my mind like calculus.

And I love math's symmetry. When I see examples like:
1x1 : 1

11x11 : 121

111x111 : 12321

111x111 : 1234321


This IMO is proof we humans have raised our level of thinking to comprehend numbers aren't just symbols to add or subtract. We've learned we can make formulas, determine medicinal dosage, hypothesize where to launch a satellite----and it gets there!!!
so if we can't find an end number in our minds, chances are we won't find an end number to the universe as in 999 quintillion miles away.
Somehow math and the universe are tied together. To understand our universe one has to have some understanding of math.
To learn our table of elements shows what happens when a single proton or electron is added or subtracted is more proof that math isnt an invention of man.
So smoothly flowing that allows us to learn gases, liquids, solids, minerals, oh the beauty of math symmetry!



I'll end on this note- one person whom I follow from a spiritual perspective (religion) impressed upon me that if we were to have a conversation with the messiah, on how we were created (his/her) language would be closer to calculi than English, Arabic etc.