finite or infinite?

[kerbouchard]

Yes, he's right.

The length of the universe/time is measurable in light years.

My physics teacher actually used a very similar balloon metaphor when explaining the nature of the universe to me.

Granted, his metaphor wasn't about the same thing as this, but it is still relevant.

(I think I asked him why mass wasn't being added to the universe if it was constantly expanding. The answer blew my mind and shoved it up my ass.)

The balloon metaphor doesn't work for that, because you ARE adding mass when you inflate a balloon.

Not at all - increasing the energy of the gasses in the balloon would result in expansion without adding mass.

But when you inflate a balloon you aren't adding energy, you're pumping in more gas

The baloon inflates because of an increase in internal pressure relative to the surrounding medium. This can be achieved by adding additional gas certainly. It can also be done by heating the gas (the adding energy bit). Or, one could simply lower the external pressure.

Lower the external pressure by putting it in a vaccum like space? The balloon is the perfect example if you could imagine a special balloon that would never pop and stuck it into a vaccum like space it would continue to expand forever, since the internal pressure is always greater than the surrounding vaccum.

A lot of the arguements about this seem to be based on the fact that it's expanding. So I wonder, if the universe suddenly and instaneously switch directions right now and began shrinking at the same rate it had been expanding, would it still be infinite?

 

[Jewrean]

If I had to pick sides I would go with the other guy. Although I hate religion and creationism. There is only one thing that is infinite and that is existence and time quite simply because long after the human race is extinct we will not be able to grasp the idea and perception that existence has ended nor began simply because we were not there to witness and observe the data nor would we be able to come to the conclusion that existence has ended because we won't exist to make that conscious thought. Everything else (whether it remains static or is dynamically changing) is finite.

 

[Tharwen]

Do you honestly believe that a few billion atoms just happened to decide to hang out together at the right place, at the right time, then suddenly life happened? I find that to be a horribly long shot.

Well the Universe is horribly large. If you choose a planet at random, the chances that it has life on it (i.e. it is Earth) are almost 1/infinity, but there are so many places in the Universe that you simply can't say "it's too unlikely".

 

[Ironic Pirate]

I have to say, kudos for having an actual discussion with someone on youtube. I haven't been able to in years.

 

[pope_of_larry]

You are righte, and debates that dont start as religious but quote the Bible will always end up going on and on, no matter what the subject unless(?) someone stops them, like one of Newton's laws that I(?) dont care to look it up.

and Furthermore, yes, things are can be(?) infinites, and if anyone says otherwise, ask them what the last number is.

Grammar Nazi Strike! Sorry to be a douche, but I really think that a contribution to an intelligent debate should be written properly.

That said, your argument is a good one; the infinity of numbers is the most easily proven of infinities. However, the counter-argument is that numbers are abstract, and therefore, since they only exist in the minds of human beings, have no bearing on discussions involving physics. Put simply, the fact humans have made up an infinite but imaginary system does not mean that anything in physics needs to be infinite

Spoiler: Here's a little thought experiment

Say I hold out my hands a meter apart. I can, obviously, divide that space in two, creating two areas of 50cm each. Each of them can be divided in half, and each of them, and so on and so forth, unto infinity. I can, of course, keep dividing them as much as I like, for there is no such thing as a minimum distance which cannot be divided, and of course the result after each division must have a finite length.

We are now left with an infinite number of infinity small yet finite distances, which I now put back together. However, as we well know, infinity times by any finite number is infinity, so my infinite number of infinitely small pieces is infinitely long.

Therefore, if infinity exists in the real world, 1 meter = an infinite distance. Since thats obviously untrue, it is obvious that infinity does not exist in reality.

We call that proof by contradiction

Sorry for my Grammar of lack of, it's not really my strong suit. there is nothing infinite that we can observe. but there are things such as space witch as far as we know has no end for all we know theres a sparky dragon that hands out cookies at the end and im not willing to take the trip to find out if it ever stops even if i do get a cookie so we may never know.

 

[ezeroast]

If I leave my house and start walking the distance between me and my house is constantly increasing. Does that make the distance between me and my house finite or infinite?

Well if you never stop walking then yep I'd say infinite.

 

[ezeroast]

Ok I accidently got into an argument with a creationist on youtube-

Fuck this thread, I'm outta here.

My thoughts exactly.

Also my first reaction.

cept it isnt about science vs religion at all, in fact, they agree about an expanding universe, its just about the definition of infinity

yea i was just after a discussion on infinity and so far so good

 

[olicon]

Do you honestly believe that a few billion atoms just happened to decide to hang out together at the right place, at the right time, then suddenly life happened? I find that to be a horribly long shot.

Well the Universe is horribly large. If you choose a planet at random, the chances that it has life on it (i.e. it is Earth) are almost 1/infinity, but there are so many places in the Universe that you simply can't say "it's too unlikely".

I wouldn't look up the statistic, but the chance of that happening would be roughly on the same level as the LHC causing a black hole, or quantum tunneling being detectable a meter away. i.e. zero.
There is always a chance of something happening. But as physicists and mathematicians would say, if it's that low, it simply cannot happen. (Why can't can't seem to apply this idea to every concept is still beyond me. But even the best of the scientific minds show can be biased at times too.)

 

[Tharwen]

Do you honestly believe that a few billion atoms just happened to decide to hang out together at the right place, at the right time, then suddenly life happened? I find that to be a horribly long shot.

Well the Universe is horribly large. If you choose a planet at random, the chances that it has life on it (i.e. it is Earth) are almost 1/infinity, but there are so many places in the Universe that you simply can't say "it's too unlikely".

I wouldn't look up the statistic, but the chance of that happening would be roughly on the same level as the LHC causing a black hole, or quantum tunneling being detectable a meter away. i.e. zero.
There is always a chance of something happening. But as physicists and mathematicians would say, if it's that low, it simply cannot happen. (Why can't can't seem to apply this idea to every concept is still beyond me. But even the best of the scientific minds show can be biased at times too.)

What? 'Effectively zero' is by no means the same as 'zero'. The universe is large enough that any chance that seems impossibly small to us is relatively significant on a universal scale. Don't just dismiss it because the chance of it happening in the tiny, tiny space we live on is near-zero.

 

[blindthrall]

Nothing is infinite.

See what I did there?

In case you didn't, the space that the universe exists in is infinite, being nothing, but the actual physical parts of the universe are finite.

That guy loses the battle... -600 HP. At any one time an expanding balloon is not finite, because it is, get this, growing, and the size is increasing. For it to be finite, it has to stay the same size and not grow at all. Our universe is going to keep expanding until it pops, so at the time right before it pops it will be finite. But until then it will be infinite. At least scientists say it will pop.

Um. When? Where? Who?

The guy that argued with *looks up at original post*...ezeroast. He lost.

No. I'm asking about the "scientists who say the universe will pop".

I've seen it on multiple documentaries. I can't remember the names of the documentaries or the names of the scientists, but it will be billions of years from now.

You watch different documentaries than I do. As far as I've heard, there's more entropy in the universe than was previously thought, due to supermassive blackholes, and the universe is looking at heat death. It's more disintegration than popping. Most of the other models violate the second law.

http://en.wikipedia.org/wiki/Heat_death_of_the_universe

 

[katsumoto03]

I'm not religious at all, but the creationist is correct.

Actually, the ruler thing was way off. You can measure things with the infinate ruler, as it would still have numbers.

 

[OmegaXIII]

All i know is that when i wear a bandanna, my ammo is infinite.

 

[Xyliss]

It could be infinite and still expanding. See Marcus DeSautoy, a mathematician who knows a lot about the concept of infinity and it's implications.

 

[ironlordthemad]

That guy loses the battle... -600 HP. At any one time an expanding balloon is not finite, because it is, get this, growing, and the size is increasing. For it to be finite, it has to stay the same size and not grow at all. Our universe is going to keep expanding until it pops, so at the time right before it pops it will be finite. But until then it will be infinite. At least scientists say it will pop.

WTF? By this logic my newborn child is infinite, at least until he's 20 and stops growing. Then again, at that point he could end up getting fat, in which case he's still growing, and thus, infinite.

How does this argument make any sense exactly?

No, that is not what I meant. I meant that since the universe is expanding at a constant rate that you cannot measure. Your child is not expanding (at least I hope not); rather, he is growing in spurts. I find it weird to talk about children so could we use another example?

Oh and you don't stop growing when you're 20, you keep going until you start shrinking with old age, just at incredibly small rates. Congrats on the newborn though.

Actually a point could be made that the child is infact infinate, at least in theory.
Its resonable to assume that the child will stop growing at some point and may even begin to start shrinking. But until the time where he stops growing, he will continue to grow, so he could become any size, until he stops growing, he is possibly infinate (thats why I said infinate "in theory"), but it is incredibly unlikely.

The idea of something being "infinate in theory" could possibly solve the origional problem.

Lets consider the original argument:

"Ok there is a distance between 2 object BUT that distance is forever expanding, how is that not infinite?"

Looking at this from a mathematical point of view.

[Please note that I haven't done maths in a while and I don't even have a degree or any kind of advanced maths education so I'm going to use some very simple maths here. If anyone has a complex formula that proves me wrong, I'm more than willing to learn about it and admit I'm wrong, but I am fairly certain in my understanding so I am going to post it up.]

The original argument is that two objects are moving away from each other, now I have to presume that this is happening over time because otherwise I am dividing by zero and we have all seen the meme's of what happens then.
So as time increases, distance increases. Assuming this happens at a constant rate we can draw a graph that will show X as TIME and Y as DISTANCE and a straight line showing how the distance increases as time increases. Assuming that the two objects are maintaining momentum, i.e. they do not encounter friction or something that would slow them down, they maintain a constant rate. Even if this doesn't happen at a consistent rate (i.e. something happens to change the speed of one of the objects), the graph will still go on, even if at a slower rate. Assuming that nothing stops the objects moving directly away from each other and nothing stops time (No one invoke the wrath of Cthulhu or my pathetic maths will be useless!) the graph will go on and on and on and... you get my point don't you?
So the graph can go on to infinity, unless something prevents time or distance from increasing for some reason, so will the two objects moving away from each other. So the distance between the two is infinate.
HOWEVER!
If you stop time (lets say by taking a photograph or a snapshot of the two objects or somehow putting the entire space time continuum on pause) the objects will be a set distance away from one another and therefore finite, but only for that moment in time.
BUT!
Since no one mentioned taking a snap shot in time that last bit wasn't really important and I added it in to prevent someone from asking it later in case I forget what point I'm making.
ANYWAY!
My point is that IN THEORY the two objects are moving away from each other for a THEORETICALY infinite time over a THEORETICALLY infinite distance. So we can assume that they are in fact infinite, so my vote goes to whoever said that in the first place. (The double negatives in the original comment confused me so I won't name names.)
But anyway, you can't apply theory too the universe, this thing called real life gets in the way. So in theory, the two objects are infinite, but in real life its likely they will stop at some point. When they stop, you can measure them and they will be finite, until that point however, they can in theory be infinite.
I kind of want to point to Schrodinger's Cat for this point. Why? Because until we know for sure, we will not know... The objects are both finite and infinitely far apart. Arguments can be made for both sides that will be valid and logical. But until we know for sure, we will not know.
Also to anyone thinking of using something realistic and simple to prove me wrong, say for example two polo mints rolling away from one another, which can be measured with relative ease, I have to point to scale to back up my argument, I am trying to talk about an infinite distance being traversed for an infinite time by objects that remain constant for all eternity. This is the kind of size that makes a galaxy look pathetically small. For my point to look even possible, don't look at it realistically, look at it in theory and don't try and measure an infinite distance with finite measurements like metres or even light years.
Man these last paragraphs make me sound pretentious, or even like I know something about the inner workings of the universe... But just give it a read through because I honestly spent more time on this than it probably deserves.
Damned Youtube arguments... grumble grumble grumble...

 

[xXAsherahXx]

Damn, it's been a while since this thread died.

 

[Limzz]

Just to confuse matters for y'all a little more: Time has dependent existence. Were there no matter or energy in existence would there be time? Is time really anything more than an idea to relate to changes in the universe at different instances?

Infinite space is always fun to ponder. There's no answer, but I always like to follow this train of thought it's fun and thought provoking: You travel in your magic dirigible to the edge of the universe. You find a force field, a brick wall, or even nothing. That force field is the edge of the universe, but how can nothing exist behind it? Doesn't it have depth? Is the brick wall infinitely thick? Is there nothing, a vacuum, behind it and if so isn't that still something? Is Tupac hiding back there? Maybe we're engulfed in a Portal portal? Okay I'll stop now.

 

[Eclectic Dreck]

Though I don't think this will put the matter to rest, consider for a moment the fundamental ruls of mathematics in play.

First, rather than considering the (slightly) more mathematically complex example of area, instead consider something one dimensional: a number line.

This number line starts at zero and is expanding in the positive direction at a known rate. We can model this scenario using a simple equation: length = (rate of expansion) * (time elapsed). With this, if we can predict exactly how long this number line is simply by picking a point in the future.

One of the interesting things about arithmatic is that so long as both the rate of expansion and time use real numbers, the result is always going to be a real number. No matter how quick your expansion or how long a timeline you deal in the result is always a finite, measurable distance.

Of course, there is a problem with this very simple scenario: we don't know when, if ever, our length will find an end. Without boring anyone with calculus, we can use the concept of a limit into play. Here we find that our independent variable (time) could conceivably be any positive value from zero to infinity. Since we can't do math at infinity directly, we could leverage the concept of a limit. In this case, our equation may as well look something like this: result = constant value * variable. As our variable increases without bound (that is, travels towards infinity) we find that the equation has no limit - it too will increase towards infinity.

So, the question inevitably becomes, does this mean it is infinite or finite? The answer depends entirely upon the span of time. At any given instant (it doesn't matter when or where, any infinitesimal span of time will work) the value of this equation is a finite number of some size. Thus, the best answer is that the length is finite. Just because it will be infinite given infinite time means little for creatures dealing exclusively in the finite.

 

[Nouw]

Mankind's Stupidity Is Infinite and will be Forever.