Extent of space (APOD 23 Mar 2006)

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Expand view Topic review: Extent of space (APOD 23 Mar 2006)

by Dr. Skeptic » Tue Jan 08, 2008 10:19 pm

Extrapolations are valid when derived between known empirical points.

If an extrapolation is derived between a known empirical point and an assumption, it's value is limited by the predictability of the assumption.

This is another major problem with science research and reporting where "extrapolations" ignore or attempt to hide open ended assumption.

by bystander » Tue Jan 08, 2008 1:35 pm

I repeat, the inability to place an upper bound on the size of the universe does not preclude the possibility the universe is expanding (or even contracting). It does not require the universe to be in a steady state.

While we can place bounds on the size of the observable universe (even those bounds are contested), no one contends that's all there is. The best we can do is make extrapolations (guesses) about the size from uncertain data. Where's the empiricism in that?

by Dr. Skeptic » Tue Jan 08, 2008 1:27 am

My argument is not only because ∞ can't be measured and is not part of empirical science, it that observation all point to the universe is not steady state, for a multitude of reasons if the universe is not steady state it is not ∞.

- The % of H and He
- The CMB
- Redshift
- The types, placement, age of galaxies throughout the universe
- ... and so on

by bystander » Mon Jan 07, 2008 2:52 pm

Dr. Skeptic wrote:Sorry, I truly believe that using infinity in empirical science is for those who's concept of the universe is overly simplified and haven't weighed the consequences of implying it to the "big" picture.

A static universe is all but proved to be false by observations of this last year (check the Noble Prize), if the universe not static it cannot be infinite.
Arguing that the universe has to be finite because you can't measure infinity is fallacious. Not being able to set a upper limit on the size of the universe does not preclude the ability to measure its parts and obtain empirical data. Nor does it preclude the possibility that the universe is expanding.

by Dr. Skeptic » Sun Jan 06, 2008 4:40 am

NoelC wrote:So what we really need to do is to discover (or invent) tunneling on a grand scale (wormholing?), so we can get beyond this pesky speed of light limitation. Imagine being able to see farther than we can imagine. :)

I'm not arguing for or against this point, but merely bringing it up for possible discussion: What *if* the laws of physics vary depending on where you are. For example, what *if* as you approach the outer "edge" of the universe (assuming there is such a thing) that the speed of light slows, so that it is essentially infinitely far (in distance and time) to the edge. Kind of like the old "go halfway to the finish line, repeat" joke, where the physicist gives up before even starting because he knows he can never get there. Things (e.g., distant galaxies) could SEEM to be an awfully long way off, yet they might not be all that far away in some grand outside-of-space-time sense. Perhaps we're all inside a marble hanging on a cat's collar.

If one considers the universe to be the combination of the laws of physics, i.e., existence of space-time-matter itself (not just the existence of matter), then what *is* the edge (assuming there is one) likely to be like?

-Noel
You are right, Space/Time and Mass/Gravity are 100% dependent on each other. Space/Time will not exist in the absences of Mass/gravity. The volume of the universe is expanding at the speed of light (+ the rate of acceleration) from the point that matter first came into existence. Outside the volume of Space/Time nothing exists, or at least as the empirical science of today tells us.

Looking for the "End" of the universe from the viewpoint of an observer not tied to the laws of Space/Time, it would appear to be a single Planck's Length that would take a photon 13.5 billion years to cross.

Sorry, I truly believe that using infinity in empirical science is for those who's concept of the universe is overly simplified and haven't weighed the consequences of implying it to the "big" picture.


A static universe is all but proved to be false by observations of this last year (check the Noble Prize), if the universe not static it cannot be infinite.

by NoelC » Sun Jan 06, 2008 2:07 am

So what we really need to do is to discover (or invent) tunneling on a grand scale (wormholing?), so we can get beyond this pesky speed of light limitation. Imagine being able to see farther than we can imagine. :)

I'm not arguing for or against this point, but merely bringing it up for possible discussion: What *if* the laws of physics vary depending on where you are. For example, what *if* as you approach the outer "edge" of the universe (assuming there is such a thing) that the speed of light slows, so that it is essentially infinitely far (in distance and time) to the edge. Kind of like the old "go halfway to the finish line, repeat" joke, where the physicist gives up before even starting because he knows he can never get there. Things (e.g., distant galaxies) could SEEM to be an awfully long way off, yet they might not be all that far away in some grand outside-of-space-time sense. Perhaps we're all inside a marble hanging on a cat's collar.

If one considers the universe to be the combination of the laws of physics, i.e., existence of space-time-matter itself (not just the existence of matter), then what *is* the edge (assuming there is one) likely to be like?

-Noel

by Chris Peterson » Sun Jan 06, 2008 1:01 am

Dr. Skeptic wrote:The argument the the universe is infinite "because" it has not been proved to be finite is far to passive of an argument for me.
I'm not arguing that, and I don't see that anybody else is, either. The point is simply that nobody can say one way or the other whether the Universe is finite or infinite. The tools of science may be able to answer that question, but so far not. To make an absolute statement that the Universe is infinite, or that it cannot be infinite, is unscientific and reflects scientific ignorance.

I'm certainly not offended by philosophical discussion, but science and philosophy are completely different things. While philosophical reasoning may suggest directions of scientific investigation, it is not itself science, and cannot answer any questions about the physical Universe. To pass off philosophical arguments as science, however, is offensive. That is the core of pseudoscience.

by Dr. Skeptic » Sun Jan 06, 2008 12:49 am

NoelC wrote:Bah, I don't see a ban on philosophy anywhere here. If you think there's a hard distinction between science and philosophy then you need to open your eyes. Imagination and wonder have given birth to science.

And perhaps the extent of the Universe can never be known. The very determination may be non-empirical in itself. That's what's hard to swallow.

Kind of falls along the lines of "how long do you have to fish before you can determine there are no fish to be caught?"

-Noel
I agree! The debate is a chance to teach, to learn, to ponder first time concepts, understand opposing viewpoints... what could be better?

The argument the the universe is infinite "because" it has not been proved to be finite is far to passive of an argument for me.

http://www.newscientist.com/article.ns?id=dn4250

Here's an article that is somewhat speculative but contains good insight to future avenues of studies.


If one finds no interest in this discussion, simply go to one you do find interesting. Or if one finds alternative viewpoints offensive because it is upsetting to a deep-seated prejudges, education is the only cure.

by NoelC » Sat Jan 05, 2008 11:44 am

Bah, I don't see a ban on philosophy anywhere here. If you think there's a hard distinction between science and philosophy then you need to open your eyes. Imagination and wonder have given birth to science.

And perhaps the extent of the Universe can never be known. The very determination may be non-empirical in itself. That's what's hard to swallow.

Kind of falls along the lines of "how long do you have to fish before you can determine there are no fish to be caught?"

-Noel

by Chris Peterson » Sat Jan 05, 2008 12:20 am

This discussion has been going in circles for quite some time now.

The bottom line is simple. From a scientific standpoint, it is currently unknown if the Universe is infinite. Nothing requires it and nothing precludes it. It isn't even known if the extent of the Universe can be determined. There are valid theories (really, variant theories) that propose each possibility; none have been falsified, and in most cases the technology doesn't yet exist to fully test and possibly falsify any theory.

Philosophical discussions about the nature of infinity are rather out of place here.

by Dr. Skeptic » Sat Jan 05, 2008 12:07 am

I'm not so sure an infinite universe can be called 'non-empirical'
If it cannot be measured or assigned a value it is non-empirical.
Empirical
From Wikipedia, the free encyclopedia


A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, that is, dependent on evidence or consequences that are observable by the senses. Empirical data is data that is produced by experiment or observation.[1] It is usually differentiated from the philosophic usage of empiricism by the use of the adjective "empirical" or the adverb "empirically." "Empirical" as an adjective or adverb is used in conjunction with both the natural and social sciences, and refers to the use of working hypotheses that are testable using observation or experiment. In this sense of the word, scientific statements are subject to and derived from our experiences or observations.
The blending of empirical and non-empirical data is a common practice these days by people with a deceptive agenda trying (and many times being successful) to pass non scientific theories as real science, or, by those that don't understand the scientific implications of blending empirical and non-empirical values.

[Publish or perish]

An example of empirical/non-empirical blending distorting science.

http://www.sciam.com/article.cfm?id=whe ... iverse-exp

by Qev » Fri Jan 04, 2008 9:41 pm

There are no measurement problems with an infinite universe. That I measure a distance of 1m between myself and my computer monitor is not dependent on whether the universe is 100 billion light years in scope, or infinite. The only measurements that make any sense are those between chosen points.

Going by the definition of 'empirical', I'm not so sure an infinite universe can be called 'non-empirical'. All that is required is evidence based on observation by our senses. If continued studies of cosmological phenomena lead us to a point where the only valid theoretical shape for the universe is one that is infinite in extent, then it is most certainly empirical. Certain classes of finite universe have already been ruled out by observations of the CMB, and some classes of infinite universe have also been ruled out by other observations.

Re: 1 ; 2 ; infinity

by Dr. Skeptic » Fri Jan 04, 2008 12:55 pm

kovil wrote:The Universe is both/and; it is both empirical and conceptual, at the same time.

Likewise it is both/and; it is both finite and infinite, at the same time.

It is a matter of which way you are looking at it, at the time.

You can see it as Ying or as Yang, it is both/and.

The Universe is not an either/or situation it is a both/and situation.

Infinity is not a quantifiable quantity, so one cannot use it like a number in an equation that is operated. It can stand in an equation that is not operated to give a numerical answer,, but is standing to elucidate a relationship.
You are correct, it is both.

My point is that the units of measurements cannot be interchanged, using empirical based science to "quantify" observations.
From Wikipedia,

Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. It is based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning.[1] A scientific method consists of the collection of data through observation and experimentation, and the formulation and testing of hypotheses.[2]
Because infinity cannot be assigned a measurable value or tested, it cannot be part of empirical science, thus it is not a scientific solution for quantifying the size of the universe.

1 ; 2 ; infinity

by kovil » Fri Jan 04, 2008 6:46 am

The Universe is both/and; it is both empirical and conceptual, at the same time.

Likewise it is both/and; it is both finite and infinite, at the same time.

It is a matter of which way you are looking at it, at the time.

You can see it as Ying or as Yang, it is both/and.

The Universe is not an either/or situation it is a both/and situation.

Infinity is not a quantifiable quantity, so one cannot use it like a number in an equation that is operated. It can stand in an equation that is not operated to give a numerical answer,, but is standing to elucidate a relationship.

by Dr. Skeptic » Thu Jan 03, 2008 11:16 pm

Infinity is not a value.

I'm not quite sure what this last bit is trying to explain, considering the 'conceptual universe' and the 'empirical universe' are already the same place.
Stating the universe is ∞, you are assigning an empirical value to it, if not, you are stating that the universe is non-empirical.

There must be a finite limit both small and large; you have to stop measuring somewhere for empirical measurements of the universe to be valid. It cannot be an arbitrary point, it must be set by empirical laws of nature, if not, it is rendered conceptual - which is non-empirical. When relating or blending a conceptual value to/with an empirical value the product will always be conceptual - not empirical.

Science's cornerstone is empirical data, without a proof set showing that ∞ is assigned an empirical value your arguments remain false.

It is true we "live" in both a conceptual and empirical universe and they are in the same place ... a rock under our feet does not, it is totally passive to the empirical universe and reacts to the universe by strict empirical behavior, properties of life on the other hand are based on non-empirical concepts and cannot be measured using empirical tools.


And please, don't go to the argument: does the rock even exist if we don't conceive it first.

by bystander » Thu Jan 03, 2008 10:10 pm

Qev wrote:You can't apply mathematical functions to ∞ to get a 'product' in the first place; it's not a number.
-- snip --
Infinity is not a value.
Actually, you can. Mathematics is just a set of rules, and as long as those rules are defined, they can be applied. Arithmetic operations are defined for ±∞ as well as for infinite limits. Infinity may not be a number but it does have value. n/∞ is defined and is equal to 0 as long as -∞ < n < ∞. All arithmetic operations are defined for infinity. (http://en.wikipedia.org/wiki/Extended_real_number_line)

However, I have to agree with your other arguments, just because the universe is infinite doesn't mean that everything within that universe becomes unknowable or unmeasurable. Observations and empirical data still have meaning.

Quantum mechanics is just a theory and it does not explain everything. For instance, it does not explain gravity. General relativity is at odds with quantum mechanics, particularly on the subject of gravity. Even if quantum mechanics was the "one truth", I can not see why there has to be a finite number of plank lengths.

by craterchains » Thu Jan 03, 2008 10:04 pm

This is kind of like watching a verble ping pong match, only with typing. :lol:

by Qev » Thu Jan 03, 2008 6:48 pm

Dr. Skeptic wrote:There needs to be a quantum limit to the number of Planck's length, it maybe static or it maybe fluid, but it is finite. Without a assigning a finite value to the universe, it takes on the equivalents as an undefinable religion where empirical data is irrelevant.
No, it just takes on the equivalent of being a very large, unbounded region. The distance between myself and my coffee cup doesn't care how much possible distance exists behind it. The only distances that are meaningful are those between points we choose to measure from.
To state that the universe is ∞ and is expanding is nonsensical to both physics and mathematics - a non-limit cannot increase, cannot be defined (other than no limit), cannot belong to a ratio ...
Neither physics nor mathematics have a problem with an infinite universe. The metric of an infinite space can expand just fine. The infinite space remains infinite, the distance between any two arbitrary points in that space increases. It's not like it's going to run out of room...
Any mathematical function applied to ∞ leaves ∞ as the product, infinity cannot be altered.
You can't apply mathematical functions to ∞ to get a 'product' in the first place; it's not a number.
Let my try and explain it this way:
Let's say there are two universes, the empirical universe and the conceptual universe. The empirical universe is where "stuff" resides; Mass/gravity and Space/Time. Then there is the conceptual universe where thought, feelings, and if you want, religion reside.
The two universes cannot be "blended" until either; conceptions are assigned empirical values or empirical values are defined as pure products of conception where the empirical units do not require an empirical definitions. Assigning ∞ as an empirical value not only to the size of the universe but "in" the universe is invalid. (mathematics uses the approach to ∞)

Any questions?
Infinity is not a value.

I'm not quite sure what this last bit is trying to explain, considering the 'conceptual universe' and the 'empirical universe' are already the same place.

by Dr. Skeptic » Thu Jan 03, 2008 4:25 pm

Try reading Steven Hawking, as he also states the the universe is granular with the Planck's Length being the absolute smallest possible size of the granules. If you have another theory that accounts for quantum mechanics (or disproves it), I'd love to hear it.

There needs to be a quantum limit to the number of Planck's length, it maybe static or it maybe fluid, but it is finite. Without a assigning a finite value to the universe, it takes on the equivalents as an undefinable religion where empirical data is irrelevant.

To state that the universe is ∞ and is expanding is nonsensical to both physics and mathematics - a non-limit cannot increase, cannot be defined (other than no limit), cannot belong to a ratio ...

Any mathematical function applied to ∞ leaves ∞ as the product, infinity cannot be altered.

Let my try and explain it this way:
Let's say there are two universes, the empirical universe and the conceptual universe. The empirical universe is where "stuff" resides; Mass/gravity and Space/Time. Then there is the conceptual universe where thought, feelings, and if you want, religion reside.
The two universes cannot be "blended" until either; conceptions are assigned empirical values or empirical values are defined as pure products of conception where the empirical units do not require an empirical definitions. Assigning ∞ as an empirical value not only to the size of the universe but "in" the universe is invalid. (mathematics uses the approach to ∞)

Any questions?

by Qev » Thu Jan 03, 2008 6:25 am

Phil G wrote:
Qev wrote:
bystander wrote:Infinity means without boundaries. It is said there is no edge of the universe (no boundary). So, by definition, isn't it infinite?
Not necessarily. The universe can be 'boundless, but finite'. A decent two-dimensional analogy is the surface of a sphere. It has no boundary (you can never encounter an edge while your motion is confined to the two-dimensional surface), and yet it has a finite surface area.
First of all, since when is a sphere, or its surface, two-dimensional? Or was that just a typo?

Then, isn't the surface of a sphere its boundary?

Peace, Phil G
A sphere is a three-dimensional shape, most certainly. The surface of a sphere, ignoring the volume it encloses, is two-dimensional. If you were a two-dimensional being living on the surface of a sphere, the directions 'up' off the surface of the sphere, and 'down' towards its center wouldn't exist for you. This is basically an (imperfect) analogy of possible ways that space can be curved.

by Chris Peterson » Thu Jan 03, 2008 2:53 am

Phil G wrote:My non-scientifically-trained mind is having trouble with this.
I presume that Planck's Lengths are mathematical units. Correct?
No, a Planck length is a unit of absolute distance, 1.6 e -35 meters. It's not a simple concept, but you can read about it in this Wikipedia article.

by Phil G » Thu Jan 03, 2008 2:16 am

Dr. Skeptic wrote:To over simplify the point, A Planck's Length is the smallest measure of distance, 1/2 of a Planck's Length does not exist.
My non-scientifically-trained mind is having trouble with this.
I presume that Planck's Lengths are mathematical units. Correct? [It's not in my dictionary.]
If that is so, then they would be integers or rational numbers, right?
How can an integer or rational number not be divisible yet again?
At least not until it has become infinitely small.
So, then, is a Planck's Length infinitely small?

Or am I just way too far in over my head?
Peace, Phil G

by Phil G » Thu Jan 03, 2008 1:40 am

Qev wrote:
bystander wrote:Infinity means without boundaries. It is said there is no edge of the universe (no boundary). So, by definition, isn't it infinite?
Not necessarily. The universe can be 'boundless, but finite'. A decent two-dimensional analogy is the surface of a sphere. It has no boundary (you can never encounter an edge while your motion is confined to the two-dimensional surface), and yet it has a finite surface area.
First of all, since when is a sphere, or its surface, two-dimensional? Or was that just a typo?

Then, isn't the surface of a sphere its boundary?

Peace, Phil G

by Phil G » Thu Jan 03, 2008 1:18 am

Dr. Skeptic wrote:Empirical measurements of the universe are meaningless if the universe is infinite.
May this non-scientist ask, Why?
Dr. Skeptic wrote:If the "Whole" cannot be measured, how can a "Part" be measured based on the same measuring criteria?
I don't understand this. It sounds like: We can't measure the distance to the moon because we can't measure the distance to a galaxy so far away it can barely be seen.

Peace, Phil G

by Phil G » Thu Jan 03, 2008 12:58 am

One: I'm fully aware of the definition of infinity, infinity is simply no limit.
Two: That isn't any definition of infinity I've ever encountered.
One: Let's hear your definition of infinity if you don't like mine.

From Merriam-Webster's 10th Collegiate [not a scientific] dictionary:

infinity noun (14c)
1 a : the quality of being infinite
.. b : unlimited extent of time, space, or quantity : boundlessness
2 : an indefinitely great number or amount <an infinity of stars>
3 a : the limit of the value of a function or variable when it tends to become numerically larger than any preassigned finite number
.. b : a part of a geometric magnitude that lies beyond any part whose distance from a given reference position is finite <do parallel lines ever meet if they extend to infinity>
c : a transfinite number (as aleph-null)
4 : a distance so great that the rays of light from a point source at that distance may be regarded as parallel

(C)1996 Zane Publishing, Inc. and Merriam-Webster, Incorporated. All rights reserved.

02/Jan/08 is the first time I've read this thread, and I've found it interesting, if somewhat repetitive. Except for a couple minor incidents, this has been a civil argument, so a round of applause to all participants.

Apparently, according to M-W, infinity did not exist before the 14th century. Or do they only mean as a noun, or human concept? ;-)

Back in the 40s-50s when I was in school, I was told that infinity [as a mathematical concept] includes everything. Therefore 1 or 73 [e.g.] can not be added to it, since they already exist within it.
Peace, Phil G

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