No Space Beyond Universe?

[Father Heathen]

Your question is nonsensical. Space is something inside the universe. There may be something outside the universe but it isn't space.

Isn't "space" an infinite vacuum?

 

[Panda]

Isn't "space" an infinite vacuum?

Is space the vacuum (or near vacuum) or is space what the vacuum is in?

In a mathematical sense space is just co-ordinates. Einstein then expanded our 3 dimensional understanding to a four dimensional one including time as a position.

 

[Father Heathen]

Is space the vacuum (or near vacuum) or is space what the vacuum is in?

In a mathematical sense space is just co-ordinates. Einstein then expanded our 3 dimensional understanding to a four dimensional one including time as a position.

Even in the mathematical sense doesn't it all expand indefinitely, unless it "loops" around like Pac Man?

 

[Panda]

Even in the mathematical sense doesn't it all expand indefinitely, unless it "loops" around like Pac Man?

The topology of the universe is unknown. It may be flat, spherical, hyperbolic or it may even be some more exotic shape.

 

[Storm]

The topology of the universe is unknown. It may be flat, spherical, hyperbolic or it may even be some more exotic shape.

Now see... if it has a shape, it has borders. If it has borders, something lies beyond them.

 

[Father Heathen]

The topology of the universe is unknown. It may be flat, spherical, hyperbolic or it may even be some more exotic shape.

What would define the boundaries?

 

[Panda]

Now see... if it has a shape, it has borders. If it has borders, something lies beyond them.

Why does something need to be outside it? That sort of statement is so far beyond our understanding that any answer would be meaningless at this time.

What would define the boundaries?

Not a clue. No one knows what the universe is expanding into or if it is expanding into anything at all.

 

[The Sum of Awe]

I was speaking of vacuum, sorry. Yes, I thought that's what space meant.

"We need more space in this trunk"

"Do you have enough space to put your stuff in?"

etc.

 

[Storm]

Why does something need to be outside it? That sort of statement is so far beyond our understanding that any answer would be meaningless at this time.

Because that's what "border" means.

 

[Panda]

Because that's what "border" means.

I think boundary is the word they use not border, and either way the dictionary definition is meaningless here. We don't know what if anything is beyond the universe or if the question even makes sense, so we can't just assume there is.

 

[Panda]

I was speaking of vacuum, sorry. Yes, I thought that's what space meant.

"We need more space in this trunk"

"Do you have enough space to put your stuff in?"

etc.

We can make vacuums.

 

[The Sum of Awe]

We can make vacuums.

But why wouldn't there be vacuum outside of the universe?

 

[Panda]

But why wouldn't there be vacuum outside of the universe?

A vacuum still needs to exist inside of something.

 

[Father Heathen]

Why does something need to be outside it? That sort of statement is so far beyond our understanding that any answer would be meaningless at this time.

How can you have an inside without an outside? Personally, I always thought of "universe" as the corporeal realm that encompasses all of existence.

Not a clue. No one knows what the universe is expanding into or if it is expanding into anything at all.

Then suggesting that there are boundaries seems to be rather arbitrary, especially in regards to infinite nothingness.

 

[Father Heathen]

A vacuum still needs to exist inside of something.

No, it doesn't. The universe is just clusters of matter and energy drifting through infinite nothingness.

 

[Storm]

I think boundary is the word they use not border, and either way the dictionary definition is meaningless here. We don't know what if anything is beyond the universe or if the question even makes sense, so we can't just assume there is.

Semantic games aside, if the universe has a shape, as you were speculating earlier, that shape must be within a larger area.

 

[dust1n]

Semantic games aside, if the universe has a shape, as you were speculating earlier, that shape must be within a larger area.

I don't think it really... works... like that... and if I'm not mistaken, the math of the universe is rarely conceived as a observably geometric possibility. Some fun stuff:

The universe versus the observable universe

Some parts of the universe may simply be too far away for the light emitted from there at any moment since the Big Bang to have had enough time to reach Earth at present, so these portions of the universe would currently lie outside the observable universe. In the future the light from distant galaxies will have had more time to travel, so some regions not currently observable will become observable in the future. However, due to Hubble's law regions sufficiently distant from us are expanding away from us much faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is expanding; see uses of the proper distance for a discussion), and the expansion rate appears to be accelerating due to dark energy. Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a "future visibility limit" beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit can never reach points that are expanding away from us at less than the speed of light (a subtlety here is that because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from us just a bit faster than light does manage to emit a signal which reaches us eventually[5][6]). This future visibility limit is calculated to be at a comoving distance of 19 billion parsecs (62 billion light years), which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.[1][7]


Though in principle more galaxies will become observable in the future, in practice an increasing number of galaxies will become extremely redshifted due to ongoing expansion, so much so that they will seem to disappear from view and become invisible.[8][9][10] An additional subtlety is that a galaxy at a given comoving distance is defined to lie within the "observable universe" if we can receive signals emitted by the galaxy at any age in its past history (say, a signal sent from the galaxy only 500 million years after the Big Bang), but because of the universe's expansion, there may be some later age at which a signal sent from the same galaxy will never be able to reach us at any point in the infinite future (so for example we might never see what the galaxy looked like 10 billion years after the Big Bang),[11] even though it remains at the same comoving distance (comoving distance is defined to be constant with time, unlike proper distance which is used to define recession velocity due to the expansion of space) which is less than the comoving radius of the observable universe. This fact can be used to define a type of cosmic event horizon whose distance from us changes over time; for example, the current distance to this horizon is about 16 billion light years, meaning that a signal from an event happening at present would eventually be able to reach us in the future if the event was less than 16 billion light years away, but the signal would never reach us if the event was more than 16 billion light years away.[5]


Both popular and professional research articles in cosmology often use the term "universe" to mean "observable universe". This can be justified on the grounds that we can never know anything by direct experimentation about any part of the universe that is causally disconnected from us, although many credible theories require a total universe much larger than the observable universe. No evidence exists to suggest that the boundary of the observable universe constitutes a boundary on the universe as a whole, nor do any of the mainstream cosmological models propose that the universe has any physical boundary in the first place, though some models propose it could be finite but unbounded, like a higher-dimensional analogue of the 2D surface of a sphere which is finite in area but has no edge. It is plausible that the galaxies within our observable universe represent only a minuscule fraction of the galaxies in the universe. According to the theory of cosmic inflation and its founder, Alan Guth, if it is assumed that inflation began about 10−37 seconds after the Big Bang, then with the plausible assumption that the size of the universe at this time was approximately equal to the speed of light times its age, that would suggest that at present the entire universe's size is at least 1023 times larger than the size of the observable universe.[12]


If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe. It is difficult to test this hypothesis experimentally because different images of a galaxy would show different eras in its history, and consequently might appear quite different. A 2004 paper[13] claims to establish a lower bound of 24 gigaparsecs (78 billion light-years) on the diameter of the whole universe, meaning the smallest possible diameter for the whole universe would be only slightly smaller than the observable universe (and this is only a lower bound, so the whole universe could be much larger, even infinite). This value is based on matching-circle analysis of the WMAP data; this approach has been disputed.[14]

 

[dust1n]

[cont.]

[AND THE CRAZY STUFFFF]


Large-scale structure

Sky surveys and mappings of the various wavelength bands of electromagnetic radiation (in particular 21-cm emission) have yielded much information on the content and character of the universe's structure. The organization of structure appears to follow as a hierarchical model with organization up to the scale of superclusters and filaments. Larger than this, there seems to be no continued structure, a phenomenon which has been referred to as the End of Greatness.

The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form clusters and superclusters that are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the universe in every direction. However, based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus.[32] It coincides with the 'WMAP Cold Spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across.


In more recent studies the universe appears as a collection of giant bubble-like voids separated by sheets and filaments of galaxies, with the superclusters appearing as occasional relatively dense nodes. This network is clearly visible in the 2dF Galaxy Redshift Survey. In the figure a 3-D reconstruction of the inner parts of the survey is shown, revealing an impressive view on the cosmic structures in the nearby universe. Several superclusters stand out, such as the Sloan Great Wall, the largest structure in the universe known to date.
End of Greatness

The End of Greatness is an observational scale discovered at roughly 100 Mpc (roughly 300 million lightyears) where the lumpiness seen in the large-scale structure of the universe is homogenized and isotropized as per the Cosmological Principle. The superclusters and filaments seen in smaller surveys are randomized to the extent that the smooth distribution of the universe is visually apparent. It was not until the redshift surveys of the 1990s were completed that this scale could accurately be observed.[33]

Observable universe - Wikipedia, the free encyclopedia

 

[tumbleweed41]

Now see... if it has a shape, it has borders. If it has borders, something lies beyond them.

Define "something".

If what we know within our universe is defined by matter/energy and space/time, then how can we even define that which is not bound by the known laws of matter/energy and space/time?

Yes, the universe has boundaries. The evidence for the Big Bang event is conclusive, possibly irrefutable, thus time and space have a beginning within the Singularity.
This indicates that because the Universe/Singularity is expanding, and space/time and matter energy are contained within the Universe/Singularity, that there must be a boundary, or an end of space/time. But "beyond" the universe is as meaningless as "before" time.



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[Panda]

No, it doesn't. The universe is just clusters of matter and energy drifting through infinite nothingness.

But it is still existing in something. If there was nothing then there would be nothing or no where for a vacuum to exist. The idea of nothingness isn't something humans (or myself anyway) can easily comprehend.

Semantic games aside, if the universe has a shape, as you were speculating earlier, that shape must be within a larger area.

dust1n and tumbleweed41 answered this I think but the short answer is no it doesn't