Friars School

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## Is the universe finite or infinte.

The two scenarios in the debate:

The universe is infinte because numbers are infinite, and something that is finite cannot contain something that is infinite.
E.G a chocolate bar cannot contain infinite cocoa.

The universe is finite, it as a beginning and end, and there is no such thing as infinite numbers because the biggest number would be the amount of the smallest quanta contained in the universe.
E.G the amount of the smallest particle in the universe = the biggest number

These two are currently merged and I believe in modern day science they contradict each other.

Feel free to add more points to the discussion

• #### Matthieu Miossec

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Aug 2 2011: Ah but what dimension are we looking at? Space or time? That is the question in the question
• #### J Ali

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Aug 2 2011: As long as the universe is fully material....then matter is finite...because an infinite thing cannot be divided...while matter can..just think of matter..then make it two...and then make those two 4...so the universe is finite...also the universe expands and anything that expands is finite..numbers are also finite....think of the highest number anyone has ever thought of...then add one to it...anything which more can be added to is not infinite. Matter is finite.. The Universe is matter.
• #### Luciano Anastassiou

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Aug 2 2011: Very good points here, I believe so as well, but the real thing is, if you conitnued to add 1 to that biggest number and someone continued it for u when u died, it would go on for infinity, so the it gets confusing because you might think that the universe is then infinite cuz of the chocolate bar example I gave, something finite cannot contain something infinite. Hard to think of haha
• #### jeroen redegeld

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Aug 18 2011: An infinite number is an human construct, it exists in oir mind. So we can conceptuallise somerhing that does not neccesarily exists.On the other hand certain quantum equations show infinity. For instance the singularity as in black holes.And m-theory shows an infinite number of universes.
also matter and energy are interchangable, divert all matter into energy and how do you propose to devide a wave function? you could go at it indefinently, infinitely.

also see:
http://sci.tech-archive.net/Archive/sci.physics.relativity/2007-10/msg00797.html
• #### Kristofer Björnson

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Aug 2 2011: You make a logic mistake when you assume that something that is infinite not can be divided. Think of the numbers 1, 2, 3, etc. Even if we continued counting as Luciano proposes, we would never in any amount of time however long run out of numbers (we may have to invent not yet existing names as the numbers get bigger and bigger though). There are infinitely many numbers, but still 7 is a single number. The infinite can thus be divided.

Also, the expansion you reffer to is the fact that the distance between galaxies does expand, and the visible part of the universe expands. Once again imagine an infinite line of number, an infinite measuring rod that has the numbers 1, 2, 3, etc. written an inch apart. Now if you come back a week later and see that each number is spaced two inches apart you would conclude that the measuring rod is indeed expanding, yet it is infinite. It's therefore not a contradiction that the universe would be infinite, but still expanding.
• #### Luciano Anastassiou

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Aug 2 2011: Good explanation, it would be like the scale expanding, but not actually expanding, so like lets say 1 2 and 3 are each a meter apart, and by expanding the actual defining length of a meter, you are stretching the numbers apart, expanding them, but they are still each a meter apart,. The only thing that changed was the defining length of a meter. This reminds me of the thought that there is no way to tell if everyone perceives time the same. For example I may experience 3 seconds as you would experience 1 second, but to the both of us it would still be defined as 1 second.
• #### Tim blackburn

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Aug 2 2011: if something couldnt be destroryed, could it be infinite?
• #### Luciano Anastassiou

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Aug 2 2011: Interesting thought, but seeing as energy cannot be destroyed nor created, it means energy would be infinite, which brings us back to square 1. Is there infinite energy in the universe?
• #### Tim blackburn

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Aug 2 2011: energy is infinite and is in the universe. so yes, there is.
• #### Luciano Anastassiou

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Aug 2 2011: I feel like using this as the conclusion, but I am not 100% certain that because something cannot be destroyed it's infinite. Energy can't be created or destroyed but does not nescessarily mean it's infinite, like if there is 2J of potential energy in something - It can't be created or destroyed but it's still 2 Joules... not infinite Joules. Besides all of the above, Energy is just a concept we use to understand many physical concepts, it doesn't actually exist, just like numbers.
• #### Sanyu Nagenda

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Aug 2 2011: Then what actually exists, Luciano? Seems that perhaps you are getting at an entirely different topic with that statement.

Besides, energy cannot be created or destroyed by OUR species.
• #### Tim blackburn

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Aug 2 2011: energy does exsist, you can even see it. i dont think it points to a difinitive answere, but how could something infinite exisit in something finite? if all matter is energy and energy is not created or destroyed and the universe thus far, as we know it, is made up of nothing but matter than what? BUT time, time IS finite, and a expanding universe is acctually slowing the concept of time, and one day, it will reach a point so slow it will be hard to say its moving at all.

if u ask me, numbers are the construct, not energy.,
• #### Luciano Anastassiou

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Aug 3 2011: interesting...
• #### Tim blackburn

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Aug 3 2011: i could use a lot more research about this though.... i probably do not know much.
• #### James Turner

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Aug 2 2011: Maybe the universe is infinite in it's finiteness. Ends with no final ending and beginnings with no ultimate start.
Does this make any sense?? Maybe with each thought we create the universe. Maybe as a character from Terry Prachett's Disc World says the universe is destroyed and created every instant but it is so quick we cannot perceive it. I think if was one of his Unseen University students like Rincewind.
• #### Luke Ginter

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Jul 31 2011: That doesn't make sense, if the universe ended but was still expanding then it would still exist
• #### Prakar Jeevan

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Aug 26 2011: I think, Space can never be finite , what is built in this space creates what we call as finite. To build something we need a base
• #### Dick Byrd

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Aug 21 2011: Jeroen:
I. certainly did not mean to imply that the Universe might not go on forever in the future, just that it definitely could not have already existed forever back in time.

2. If the energy density in the Universe approaches zero asymptotically over time, as you suggest, then in an infinite amount of time it would have reached zero, or more technically - infinitesimally small. That definitely is NOT the Universe we observe, hence it could not have existed for an infinite amount of time.

3. It is difficult to say anything about any Universe, or part of the Universe, that cannot be observed. So, I can only say that THIS Universe that we live in and we observe is finite in time and space,

Dick
• #### Dick Byrd

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Aug 20 2011: The Universe must be finite in time and size. The 2nd Law of Thermodynamics (Law of Entropy) demands that energy is always dissipated in every process. If the Universe had been here infinite time, all energy would be dissipated and there would be no useful energy. There would be no atoms, no elements, no nothing.
The Universe is expanding. If it had been expanding for infinite time, regardless of the expansion rate, the density of matter in the universe would now be zero. It is not, therefore the universe has not been here for an infinite time. Likewise, if the universe were infinite in size, all of the matter generated in the big bang would now all be dissipated throughout an infinite space, and the density would be zero. This does not describe the universe we live in. The density of matter is not zero, and there is useful energetic processes going on. The universe is finite.
• #### jeroen redegeld

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Aug 21 2011: Even infinity has to start at zero, the universe is 13.7 billion tests old. It could go on indefinently. That somerhing has à starting point dorsn't mean it isn't infinite.

Yes energy dissipates, but it is not destroyed, that would violate the first law of thermodynamics. even if an infinite space would hold a finite amount of energy, the system would never reach zero, just asymptotically aproach zero. even an infinite space would not be an absolute vacuüm if it contained one photon.

We can only say somerhing about the amount of matter in the observable universe, we don't know what is beyond that, it might even be infinity.
• #### Mountain River

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Aug 19 2011: I've tried, but no matter what I do I can't even imagine the universe as finite. How do you do that?

The only descriptions of finite universes that I know of are bubble universes. These presumptions are based on the flawed perception that bubble universes are finite. Incorrect. The empty void around the bubble universe that the bubble is expanding into is a part of the universe as well.

How could existence be finite? The only real explanation I've heard so far is "positively curved circle" theory... but even that makes little sense to me. Why is the universe suddenly finite when it is a positively curved circle? Doesn't the empty (possibly not empty) void around it constitute "universe?"

If anyone can explain exactly HOW all of existence can be contained by... itself (because an "outside" would constitute more universe)... I'd like to hear it.
• #### jeroen redegeld

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Aug 18 2011: Cosmologists are hung on the idea if this single universe is finite or infinite.
See the BBC horizon documentary "to infinity and beyond" on YouTube .
Deen it? Now i have à question.
If THE universe is infinite and an infinite number of things happen in it, then the universe can not be infinite.
One of the possibilities would be conditions happenig to allouw the universe to end, wouldn't it?

Also it's not clear if the possibilities would have to adhere to the fundamental laws of physics within this universe. So for instance can the DBZ saga be playing out somwhere?
These two considderations are not clear to me.
Any thoughts?
• #### Matthieu Miossec

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Aug 19 2011: I think that even with the universe being inifinite, only things within the laws of physics could happen. What we would see however are things that seem impossible while not violating the laws of physics. While it is statistically near impossible for evolution to take place on another planet so as to come up with a species identical to human beings, in an infinite universe, this not only can happen, it WILL happen.

I don't remember this particular BBC show advancing the idea of a universe as more than a thought experiment. But it's been a while since I have seen it. My understanding is that the Big Bang implies a finite universe at least in some dimension of space.
• #### jeroen redegeld

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Aug 19 2011: I think they mean infinite in space and time. if it is infinite in this way then it wouldn't surprise me that somewhere a civilisation already has thrived and died with the exacat same genome as us. what bends my mind is that is has to happen an infinite number of times.
somewhere someone with the same DNA is typing the same thoughts real time as me.
on the other hand. does infinity in this respect mean that everything neccesarily must hapen? it is a game of probability some impossible thing might happen a thousand times, others maby never ( it is a logical implidcation of infinity, paradoxical, but logic non the less)

and if i understood correct, it isn't a thought experiment. there is a distinction between the visible universe and beyond.
because of expantion light beyond the distance of the age of the universe can never reach us. so cosmologists have no idea what is beyond visible space. hence the question if it is finite or infinite.

i do understan that if it is the concept of infinity within the bounds of physics then it isn't truely infinite either anything we can dream of must happen or it is just every possible combination, a large number, but certainly not infinite.
• #### Patrick McCarthy

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Aug 7 2011: Taking this question less seriously, I would like to propose the following:

The Universe is not a thing, therefore, neither infinite or finite. I say that the Universe is in us, in consciousness and we are in the Universe. Looking at the word, Universe, breaking it down gives us "one-song," perhaps that may mean that any song played or sung out of harmony can have no life in it, as such. Therefore this might imply that Truth and Intelligence etc.,(both life giving) are both at the same time, our mental environment internally and environmentally.

Einstein may have called it the "grid," I think.

As long as we think of the Universe as being out there, requiring a telescope, we remain stuck in ignorance.
• #### Max Wagner

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Aug 5 2011: I'm not really seeing the logic point you're trying to make by saying a universe in which the natural numbers exist can't be finite. Consider this:

The universe doesn't contain an instance of every natural number. It can merely contain the natural numbers as a concept in the same way an ideal Turing Machine can theoretically enumerate every single natural number with only a finite amount of internal states (finite intelligence, infinite conceptual numbers)
Another way of putting this: just because we can think of infinite numbers doesn't mean there's infinitely many *things* in the universe.
• #### Sanyu Nagenda

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Aug 2 2011: It's infinite.

It was here LONG before us, it will be here LONG after us. Therefore what we have to say about its relative "finiteness" or "infiniteness" means very little in the Existence equation.

Our species is not the center of All, much as it bruises our ample egos. Ask the atoms (or dark matter). They know better than anything whether they are finite or constantly expanding at an ever increasing rate into infinity.
• #### Kristofer Björnson

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Aug 2 2011: No one knows. The theory that best explains universe at the moment is general relativity, and it allows for several different scenarios. The universe can be infinite, or it can be bent so much that if you go far enough in one direction you will get back to the same point you started from. In the second case the universe as a whole is very much like the surface of the earth, follow a stright line and you will eventually come back to where you started from.
• #### E G

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Aug 2 2011: does it matter?
• #### Luciano Anastassiou

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Aug 2 2011: Eduard, the same question has been asked about many things in history like "is the earth flat? - Does it matter?" and clearly it does. Well same with this scenario; in the future, it will matter A LOT if the universe is infinite or not, for example let's say a few thousand years from now or even sooner, some company decides they want to travel to the end of the universe. This would not be possible if it was infinite, and another thing is, imagine if we had fully understood wormholes and wanted to warp space-time and travel to another location, if the universe was infinite this would not be possible because every x, y, and z location in the universe would be ∞ (infinite) because it would stretch infinite metres (or whatever unit) in every direction which means we would have to use normal methods of travel which, on the scale of the universe, is very slow.
• #### E G

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Aug 3 2011: Hmm ...... perhaps in the future will exist a reason for seeking to see if the universe is infinite or not , everything's possible, but now what matter in my opinion is: US, we now and here in our usual life .........anyway ........
• #### Peter Law

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Aug 3 2011: Hi Luciano
Modern science seems to think that the universe is expanding; largely due to red-shifted light. If it is expanding then it cannot be infinite. It's going to be bigger tomorrow.
If it's not expanding then it may well be infinite.

:-)
• #### jeroen redegeld

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Aug 18 2011: Expantion means there is more room between two existing objects. Space grows apart without adding to it. The wavefront of the big bang is still perpetuating.The universe grows & expands