Is infinity a long way?

[Phil Ayesho]

The edge of the visible universe is already too far away for light to ever reach us- The edge of the universe is moving away from us faster than the speed of light.

As the expansion of the universe accelerates...more and more of the visible universe will disappear from view.

Eventually, only our own galaxy will be visible.... then only the local stars, and shortly after that... if current theory holds up as correct, molecules and mater will be torn apart by expansion, matter will cease to exist and time will end.

The universe is finite in every imaginable sense.

 

[Jovial]

Anyway, it sounded like you were saying the universe is infinite.

The universe may not be, but infinity doesn't have to be only about the size of the universe. It can describe other things, like infinitely small things. Is there a smallest distance that something can travel? Is that a smallest interval of time? It appears that we can consider an interval of time as small as we want but still be more than zero.

 

[Phil Ayesho]

You can imagine it... but it is not real.
There IS a smallest possible distance... somewhere near the Planck length... and there is a smallest possible unit of time, because there is a shortest possible event... which is the only measure of time.


Infinity, like God, like Eternity, are solely mental constructs, with no real relevance in the natural world.

 

[Hugh Mann]

That two infinite sets can be compared to each other is very interesting. Your Cantorian approach reminds me of Hilbert's Grand Hotel Paradox. If I remember correctly, he showed how a hotel with an infinite number of rooms that are all occupied could always accomodate an infinite number of additional guests. When the next guest arrives, you move the guest in room 1 to room 2, the guest in room 2 to room 3, and so forth to infinity, thereby freeing up room 1 for the new guest. Then when the next guest arrives you do the same thing, and so on.

Infinity makes my brain hurt.

It's not just your brain. Indeed, Cantor himself was driven to insanity by his discoveries. Many of his contemporairies, most notably, Kroenecker, were so offended by Cantor's works that they resorted to religious arguments to refute him when mathematical rigor failed them, such as Kroenecker's: "God made the integers; everything else is the work of man." But decades of research in math and the philosophy of mathematics have shown that the concept of higher orders of infinity does not a priori contradict reality...it raises questions as to how we deal with the comparison of arbitrary sets. Many results that remind us of our familiar finite sets (i.e., {1,2,3,4} has more elements than {1,2,3}) seem ok, but a corresponding statement for infinite sets requires a big logical jump. This jump is called the Axiom of Choice. One form of it says, that, given ANY two sets (either of which can be in infinite), there exists at least an injection of one of the sets into the other. This means that we can't compare infinite sets if we don't accept the Axiom of Choice. The acceptance of this axiom has disturbing consequences, and the rejection of the axiom has even worse (in this poster's opinion) results. I guess this is why we have logicians

 

[JustAsking]

You can imagine it... but it is not real.
There IS a smallest possible distance... somewhere near the Planck length... and there is a smallest possible unit of time, because there is a shortest possible event... which is the only measure of time.


Infinity, like God, like Eternity, are solely mental constructs, with no real relevance in the natural world.

Phil,

I respectfully reject your claim. All scientific theories are artificial mental constructs that only have value in as far as they explain or predict. As Thomas Kuhn pointed out, all scientific theories are eventually replaced by new ones that have more explanatory and predictive power, yet bear almost no resemblance to the original theory they replaced. He sees this as an indication that scientific theories are no more real than mathematical ones and their truth can only be measured by their usefulness.

So I maintain in the light of all that, that infinity is probably more real than the Planck Length.

 

[JustAsking]

... Two infinite spaces cannot coexist.

That doesn't strike me as necessarily true, but I don't have any way to refute it.

With our technology, no we can't detect the edge of the universe whether there is one or not. Not in our lifetimes. The signal would take too long to reach it and bounce back.
....

Good one. I agree with this completely. We forget that the light we see things by travels at a finite speed. So there are certainly stars that are far enough away from us such that the first light they ever emitted has not yet reached us. You don't even have to speculate about the edge of the universe to realize that.

The edge of the visible universe is already too far away for light to ever reach us- The edge of the universe is moving away from us faster than the speed of light.

As the expansion of the universe accelerates...more and more of the visible universe will disappear from view.

Eventually, only our own galaxy will be visible.... then only the local stars, and shortly after that... if current theory holds up as correct, molecules and mater will be torn apart by expansion, matter will cease to exist and time will end.

The universe is finite in every imaginable sense.

Yes. I think this is "heat death", isn't it? The universe is headed assymtotically towards complete entropy. I hate it when that happens!

But I am not sure that the edge of the universe is moving away from us faster than the speed of light. Where did you get that?

 

[Rikter8]

Infinity is simply forever.

You can't say that it doesn't exist, because no one can prove that it doesn't.
To do so, is narrow minded.
(At least at this point in time, in space)

Infinity cannot be measured, as it continues forever.

Until the Stargate is fully functional, we will never know IF there is an end to the universe.

 

[Axcess]

Infinity could be possible if the multiple bigbang theory is correct . Maybe infinite universes exists as well . If this universe is the first and only universe then infinity isn't real .

 

[Axcess]

The edge of the visible universe is already too far away for light to ever reach us- The edge of the universe is moving away from us faster than the speed of light.

As the expansion of the universe accelerates...more and more of the visible universe will disappear from view.

Eventually, only our own galaxy will be visible.... then only the local stars, and shortly after that... if current theory holds up as correct, molecules and mater will be torn apart by expansion, matter will cease to exist and time will end.

The universe is finite in every imaginable sense.

yes this universe is finite it eventually will collapses in to the big crush but some believe that the universes will expand forever .

 

[JustAsking]

....Infinity, like God, like Eternity, are solely mental constructs, with no real relevance in the natural world.

At the risk of being repetitive, the only measure of the relevance of a scientific theory is its power of explanation and prediction. For example, both the concept of infinity and the heliocentric solar system model are mental constructs that can only be evaluated for truth by their ability to make (or be essential to the making) of useful predictions about events in the natural world. Beyond that, there is no way to assign relevance to them.

All generalizations that go beyond direct measurement are mental constructs.

 

[Symphonic]

Or is it just around the corner

I was going to ask a genius but he doesn't seem to be answering my questions. Maybe one of the other clever people on here will be able to answer this question?

Right around the corner since infinite space actually works on a backwards scale. Rather than getting larger it gets smaller. For instance if you take half of your last step towards a wall you will never touch it.

 

[Phil Ayesho]

At the risk of being repetitive, the only measure of the relevance of a scientific theory is its power of explanation and prediction. For example, both the concept of infinity and the heliocentric solar system model are mental constructs that can only be evaluated for truth by their ability to make (or be essential to the making) of useful predictions about events in the natural world. Beyond that, there is no way to assign relevance to them.

All generalizations that go beyond direct measurement are mental constructs.

Two errors in logic.

1- heliocentricity is not a mental construct. Its a fact. Poor observation and a lack of imagination may have led early observers to conclude otherwise... but as observation improved, heliocentricity was clearly the only reasonable explanation that fit the facts.
Since that time, it has been directly confirmed thru direct observation.


2- predictive ability of theory has NO relation to its "truth" as a real feature of the universe.
Mathematical theories, for example, fairly accurately predict all kinds of things... but the universe does NOT DO MATH.

There are no calculations involved in the universe behaving the way it does.

ALL scientific theories are merely descriptive.
Early theory, dealing with the grossly observable world, may have tended to be more "true" than more modern theories, because they dealt with the directly apprehensible. A tree, a rock.. are real things.

But scientific theories often create imaginary constructs to invent a framework by which we can predict what will be observed. So, we can discuss a force that SEEMS real... like centrifugal force... but in fact there is no such force; the behavoir is totally emergent from Newton's laws of motion- and they do not include any such force.

So while a change in theory will not do away with a rock or a tree... changes in theory concerning more esoteric observations routinely create, or do away with forces and laws and particles that are nothing but convenient mental tricks that may or may not make our predictions more accurate.

Thus, a theory may be usefully accurate in predicting events without being in any meaningful way an accurate picture of how the universe operates.

I can solve a rubiks cube by prying it apart and re-assembling it in its starting configuration... its not the "true" solution... but it is a valid solution nonetheless. It solves the problem.


For example- flight. We have a host of equations that we use to design airplane wings... equations dealing with a force we call "lift".

But in fact there is no such force and it is NOT why planes fly. Turns out that the imaginary force of lift is not what holds a plane up... it is nothing other than thrust. A properly formed wing deflects air downward. The mass of the air deflected downward must match the mass of the plane for the plane to fly; it must exceed the mass of the plane for the plane to climb.

The theory of lift was formulated thru observations in wind tunnels... The observers came up with a formula that accurately predicted wing performance, even though they completely misunderstood the actual forces at play. Because they tinkered with the formula until its output matched observation... it works... because it works people ASSUME it says something about flight dynamics that is "true" of reality.

It doesn't.

Ergo-- it does not matter how accurately predictive are our theories that rely on infinite terms and the concept of continua ... their accuracy and usefulness in no way implies that these concepts are actual features of reality.
No matter how accurate a portrait I draw of you, ... the portrait is NOT you.


Infinity, in practice, is KNOWABLE as impossible. It is PROVABLE as being impossible. And impossible things do not exist.

Infinity is an imaginary thing.

 

[Phil Ayesho]

Yes. I think this is "heat death", isn't it? The universe is headed assymtotically towards complete entropy. I hate it when that happens!

But I am not sure that the edge of the universe is moving away from us faster than the speed of light. Where did you get that?

Heat death is what we used to think would happen... when we thought that cosmic expansion would result in an (wait of it) infinitely less dense universe... matter would cool to the point of absolute zero... no light no heat.


But the recent discovery that the cosmic expansion is ACCELERATING ( and we invented a NEW imaginary force called Dark Energy) has led to some strange findings.

If theory is correct.... ( which I suspect it is not... I really doubt we have figured this out yet) it points to the very fabric of space eventually being torn apart by this acceleration of expansion.
What I do like about his idea is that finite things ought to be finite. If reality as we know it HAD a beginning... then it must have an end.


As to the edge of the universe moving away from us faster than light...

It HAS to be. The universe IS expanding. Hubble found that, as you observe further away, the objects you see are moving AWAY from us at a speed that increases with distance.

Now- understand that these distant galaxies are not ACTUALLY moving. From THEIR perspective WE are moving away from them at high speed.

This observation must be the same everywhere in the universe.

Rather... the universe we are in is getting larger... not from the middle out, but from every point. SO the spaces between all objects are getting larger.

The common way to visualize this is to put a bunch of dots on a balloon that is only partially inflated...and then inflate it further... the dots will get a little larger, but the spaces between the dots will get larger way out of proportion.... from the perspective of any given dot it would appear that all the other dots are moving away from it. Dots farther away would appear to being moving away faster than dots closer.

Because none of the dots... none of the galaxies, are Actually in motion, the effect on the light they give off is not subject to relativistic limits on velocity. Nothing is actually moving faster than light... its just that the space between us and them is inflating so fast that light would have to exceed the speed of light to reach us from that point because that end ofd the universe and this end of the universe are getting father apart at a rate that exceeds the speed of light.


So- in 5 billion years, the quasars we can currently observe at the furthest reaches of the universe will have winked out and no longer be visible. And the early galaxies that are a little closer to us than the quasars will seem to be as far away and moving as fast as the quasars seem now.

In 20 billion years, stars that now seem quite close will appear to be at the extreme edges of the universe.... as far as quasars are now...

And- ultimately the space between quarks will have expanded to the point where matter can no longer exist.


Again... this is all assuming our theories are fairly predictive...
But they may not be.

The first spaceships we have ever sent out of our solar system are NOT where our physics SAYS they should be.

Our first trip away from home and we are finding our assumptions are false.

If the Pioneer anomaly actually means our theory of gravitation is incorrect... then that could entirely alter how we interpret the evidence that makes us come to the above conclusions.

Even a Minor change in the theory of gravity could eliminate the need for "Dark Matter"... could even eliminate the need for a big bang.

We are still little more than very clever monkeys.
The likelihood that we have even a really good handle on the processes of the universe is pretty low.

 

[mista geechee]

We are still little more than very clever monkeys.
The likelihood that we have even a really good handle on the processes of the universe is pretty low.

I was just going to say something like that. The 250k years (the blink of an eye in a geological/cosmic respect) since the dawn of modern humans hasn't nearly been enbough time to get a complete or substantial grasp on this thing we exist in that is massive beyond comprehension.

Everything we have theorized could be wrong. Carbon dating, physics, even "simple" cause and effect.

Anyway, since light would take such a long time to go to the edge of the universe and back, couldn't we use that same reasoning to say that objects we view through our space telescopes (like the Hubble) could probably not be there anymore? Or could be closer than what we have extrapolated from images, gravitational equations...etc...etc...?

 

[JustAsking]

Two errors in logic.

1- heliocentricity is not a mental construct. Its a fact. Poor observation and a lack of imagination may have led early observers to conclude otherwise... but as observation improved, heliocentricity was clearly the only reasonable explanation that fit the facts.
Since that time, it has been directly confirmed thru direct observation.


2- predictive ability of theory has NO relation to its "truth" as a real feature of the universe.
Mathematical theories, for example, fairly accurately predict all kinds of things... but the universe does NOT DO MATH.

There are no calculations involved in the universe behaving the way it does.

ALL scientific theories are merely descriptive.
Early theory, dealing with the grossly observable world, may have tended to be more "true" than more modern theories, because they dealt with the directly apprehensible. A tree, a rock.. are real things.

But scientific theories often create imaginary constructs to invent a framework by which we can predict what will be observed. So, we can discuss a force that SEEMS real... like centrifugal force... but in fact there is no such force; the behavoir is totally emergent from Newton's laws of motion- and they do not include any such force.

So while a change in theory will not do away with a rock or a tree... changes in theory concerning more esoteric observations routinely create, or do away with forces and laws and particles that are nothing but convenient mental tricks that may or may not make our predictions more accurate.

Thus, a theory may be usefully accurate in predicting events without being in any meaningful way an accurate picture of how the universe operates.

I can solve a rubiks cube by prying it apart and re-assembling it in its starting configuration... its not the "true" solution... but it is a valid solution nonetheless. It solves the problem.


For example- flight. We have a host of equations that we use to design airplane wings... equations dealing with a force we call "lift".

But in fact there is no such force and it is NOT why planes fly. Turns out that the imaginary force of lift is not what holds a plane up... it is nothing other than thrust. A properly formed wing deflects air downward. The mass of the air deflected downward must match the mass of the plane for the plane to fly; it must exceed the mass of the plane for the plane to climb.

The theory of lift was formulated thru observations in wind tunnels... The observers came up with a formula that accurately predicted wing performance, even though they completely misunderstood the actual forces at play. Because they tinkered with the formula until its output matched observation... it works... because it works people ASSUME it says something about flight dynamics that is "true" of reality.

It doesn't.

Ergo-- it does not matter how accurately predictive are our theories that rely on infinite terms and the concept of continua ... their accuracy and usefulness in no way implies that these concepts are actual features of reality.
No matter how accurate a portrait I draw of you, ... the portrait is NOT you.


Infinity, in practice, is KNOWABLE as impossible. It is PROVABLE as being impossible. And impossible things do not exist.

Infinity is an imaginary thing.

Phil,
Yes you are right about heliocentricity. I picked a bad example, because you can say that it has been rendered as fact due to direct observation. But very few theories enjoy this status.

Let me pick some better ones. Newton's laws of motion and universal gravitation. I maintain that that the universality of the laws of motion and of gravitational attraction are both mental constructs. They enjoy scientific status because they have massive explanatory and predictive powers.

However, they have not been proven to be universal, since their universality can not be observed. In other words, without testing gravity and motion everywhere in the universe, the universality of the laws of motion and gravity are only theoretical. Yes, they have had as much corroboration as any scientific theory can get, but they have not been exhaustively proven (as with all scientific theories which cannot be proven by direct observation).

So, I maintain that the universality of Newton's laws of motion is no more real than the notion of infinity. We conditionally accept them as the best explanation of the natural phenomenon they apply to, but we don't hold that they model reality. We accept them because they do a better job of explaining and predicting than any other theories we have about motion and gravity at speeds much less than the speed of light.

Furthermore, they are no less "mathematical" than the notion of infinity, in that they consist of artificial idealized properties of nature (momentum, kinetic energy, mass, etc) with relationships that are described mathematically. If you say that the universe does not "do math", you then have to accept the fact that Newton's Laws are only useful models for the real world, and not the real world itself.

In fact, Newton's Laws were subsumed by a newer theory (the relativities) which is more accurate and bears no resemblance to Newton's Laws. Over time, the theories of relatvity will also be replaced by theories that have no resemblance to relativity. Since each successive theory is completely different than the ones they replace, one must conclude that none of them are anything more than astonishingly useful artificial models, being no different than mathematical notions.

Can you honestly say that an electron exists. No scientist will admit to anything other than the notion of an electron is a useful tool for inference, and probably not a real thing at all.

 

[JustAsking]

...Anyway, since light would take such a long time to go to the edge of the universe and back, couldn't we use that same reasoning to say that objects we view through our space telescopes (like the Hubble) could probably not be there anymore? Or could be closer than what we have extrapolated from images, gravitational equations...etc...etc...?

Yes we do. Astronomers are completely aware that what they are seeing is light that has traveled immense distances for long periods of time. And it is completley possible that some of the objects they are looking at no longer exist.

However, there is an old relationship between the distance and the speed of an object in deep space called Hubble's Law. It states that the farther away an object is from us in space, the faster it is going. In that we can measure the speed of a retreating object via the shift in the light spectrum (the light equivalent of Doppler shift), we can get a rough idea of how far away something is from us. From that, knowing that the speed of light is finite, ,we can then calculate how far the object might actually be.

This is providing that Hubble's Law holds.

 

[D_Thoraxis_Biggulp]

That doesn't strike me as necessarily true, but I don't have any way to refute it.

I should've specified -- since it's been proven that there are more spacial dimensions which we don't see, ones that would lead to other universes could we move along them -- two 3-dimensional infinite spaces can't exist in one 3-dimensional space.

 

[TomSchmo]

Well i remember from a math class that infinity is just a concept meaning "increasing without bound"
So from that definition, there is no end or bound.
and once that bound is found then it cant be called infinity still since it doesnt still fit the definition.

 

[JustAsking]

I should've specified -- ...two 3-dimensional infinite spaces can't exist in one 3-dimensional space.

But that is a category error. I think you stumbled into Russell's Paradox. (I think it goes that the set of all non-tea cups includes itself.) Anyway, I don't think the two infinite 3D spaces need to exist within another 3D space.

 

[B_Nick8]

Um, kind of.