Can we conceptualise the shape of the universe?

[4x4Tyke]

Prof Prolapse said:

I think we're misunderstanding each other, perhaps it's my error. When I say it's "proven", or if I was to say, "it's a done deal", I would mean that based on the balance of probability I believe it to be the most widely held and likely truth. Nothing is certain, but I think it is fair to say, it is highly plausible that the universe is flat and open, so that is the rational position to hold.

Independent verification is a cornerstone of science. We see that through peer review in papers and reproducibility in experimental and observational studies. There are scientific theories that are proven, e.g. wave partial duality or evolution. I would accept 'proven' or 'done deal' for anything proven that way. A balance of probabilities is not equivalent to a scientific proof, proof in science is more akin to beyond a reasonable doubt.

However, while I splitting hairs on semantics with the above, I'm not on issue of the geometry of the Universe, it cannot be both flat and open, open, flat and close geometry are mutually exclusive.

Prof Prolapse said:

If you want to dispute that then I would honestly be fascinated to hear the reasons why, but it's not a rational position to simply state that a small degree of uncertainty means we should continue to exist in absolute uncertainty about the shape of the universe until it is resolved. That is my recurrent point throughout this thread, and the only one I am perhaps sufficiently confident to continue to maintain.

The experimental/observational evidence suggests the universe is flat. That doesn't mean I accept it it IS flat, but it is very close to it, within our ability to observe and measure it. Consider how we know the earth is a globe, early observation (eye level) shows the ground appears level (and bumpy), there are people that still think it is flat. One of the early Greek philosophers, who's name escapes me, was able to calculate the circumference, by indirect observation (length of shadows) and trigonometry. Leap forward and we can do the same by direct observation using satellite telescopes to know his results are very accurate. We can readily say that is proven.

I happen to think the Universe is most likely open on a Cosmological scale but appears flat on local scale for the same observational limits. We are allegorically still crawling in the sand with string with regards to measuring curvature of spacetime.

A positive curvature (open Universe) has not been proven by experiment or observation, it highly questionable to say it is even a consensus. I think the consensus is probably with flat.

Prof Prolapse said:

So yes, I agree in so much as there is a degree of uncertainty (in some of these points more than others) but I believe what I've said remains valid. My understanding for example is that "Dark matter", is just something made up because there isn't enough matter in the universe to fit the maths, it's just term. We don't have to wait until we discover what it is, that doesn't necessarily make the assumption any less valuable, or mean all of cosmology will be re-written when we find it precisely what it is.

It's like the global warming thread here, the biggest problem the naysayers have is they don't understand it isn't a house of cards waiting to tumble.

Yes agreed, Dark Matter is a hypothesis to fill certain holes in the maths. Those holes are the best candidates for enquiry, but I maintain a healthy scientific scepticism rather than objecting as I would to a flat earth or creationism theory.

We currently see no evidence of WIMPs, but AIUI there are still a long way to go to rule it in or out, likely or unlikely. Dark Energy seems more plausible to me, given our model of vacuum energy. However exotic matter is one area I'm struggling to grasp beyond a surface understanding.

Prof Prolapse said:

It's like the global warming thread here, the biggest problem the naysayers have is they don't understand it isn't a house of cards waiting to tumble.

Agreed, but this whole area of Cosmology is much less settled than climate change. I say that what makes it more settled IS the nitpickings over semantics and using probability to find potential successful avenues of investigation and confirmation.

To use another allegory, betting on favourites will eventually fall foul of probability and that is what stops it being a 'house of cards',

The only thing I really strongly disagree with is your use of the term, 'flat and open', it is not, so please take another look at the graphic and sources already given.

Edited by 4x4Tyke on Saturday 25th November 11:48

[4x4Tyke]

Prof Prolapse said:

I've mentioned Krauss twice already when it comes to the origin of the universe because I think he's a legend, his lectures are on youtube, and accessible for lay people (although I needed to watch it more than once!). Krauss also likes to argue the atheist view point.

--snipped--

Now off topic, but important, that doesn't mean life can't have value. There's masses of philosophy Existentialism is the whole philosophy which deals with the idea of defining everything via oneself as opposed to some magic bearded entity doing it for you. Similarly Nihilism, depending on your exact interpretation, doesn't mean life is without value, it just means it has no intrinsic value. I am very strong believer in Nihilism, in that pretty much reject any idea of intrinsic value (or morality but that is for another thread) but I thoroughly enjoy being alive, and recommend it to all my friends and family. Personally I devote my time to my family, what I feel is a positive use of my time, and I try and enjoy my brief time in the sun before I return to the nothingness we all came from. In many ways life has more value when it's not infinite, "a thing is not beautiful because it lasts".

This video of his, covers quite a lot of interesting stuff related to this discussion, his explanation of cosmic horizons is much better than mine. I also love his closing comment, which is something else I raised earlier in the thread. The Universe exists because we observe it. On the meaning of life I kind of take the Star Trek philosophy, we get to define our own meaning of life and I find that pretty liberating.

https://www.youtube.com/watch?v=RKapUWxTvWI

[4x4Tyke]

The end of the hunt for WIMPS?

https://www.youtube.com/watch?v=RchRrngfjQY

[Prof Prolapse]

Then I agree to agree!

4x4Tyke said:

The only thing I really strongly disagree with is your use of the term, 'flat and open', it is not, so please take another look at the graphic and sources already given.

The universe is flat, surely, given the very small margin of error we can agree on this point

I'm sorry, perhaps I missed it, I don't see how you've disputed the expansion of the universe. So I think this is perhaps a misunderstanding given the two interpretations of the phrase "open"?

When I say the "universe is open"., I am not making assumptions of curvature or geometry. I am saying that the universe is "open" as per the "dictionary.com" definition. "If there is not enough matter in the universe to exert a strong enough gravitational force to stop the universal expansion associated with the big bang, the universe is said to be open".

I honesty couldn't comment on the alternative meaning curvature sense of the phrase. I am far more fascinated by the revelation that the universe ends cold and dead.

[Mr Whippy]

I remember reading the book 'flatland' and the descriptions of the 2d world's inhabitants and how they perceived their world, and struggled to visualise the advantage of the 3D observer.
They then used a 1d world as an example to convey the advantage of the extra dimension for the 2d observer.

Long story short, you feel you can start to think in a more creative and tangible way when considering how these extra dimensions would appear if you could properly comprehend them.


Apparently the book is also an observation of the Victorian era class system, but imo the value today is in the excellent conveyance of dimensional observations and limitations.



I'm not sure the shape of the universe is all that relevant any way.

All measurement is relative. Measure away and know it's multi-dimensional properties, but applying a simple 3D shape to it is missing the point entirely.

[Atomic12C]

One thing that I think confuses people (not saying anyone on here is confused by the way), with 'more dimensions' is that there are different concepts.

One concept is additional space dimensions used in physics.
For example string theory (M-theory) requires 11 spacial dimensions (the 3 we are used to + time, and then an additional 9). These dimensions are described to be on the minute level in such that a surface is never really '2-D flat', but rather something that can be 'navigated' around (like an ant walking the 'thickness' circumference of a rope).

Another concept of additional dimensions is you can add to geometry/volumes in the language of maths.
This is the concept of taking a 1-D point and stretching it to a 2-D line. Then taking 2-D lines to form a 3-D shape which now has a property of volume.
Then the trick is to take that 3-D volume and stretch that in to a 4-D entity.... and so on. (Hyper-cubes etc.)


So additional dimensions are concepts that fit in to theories which then have proved quite successful in describing observations.
Whether additional dimensions are 'real' or not requires a 'leap of faith' I would guess.

[Efbe]

Atomic12C said:

So additional dimensions are concepts that fit in to theories which then have proved quite successful in describing observations.
Whether additional dimensions are 'real' or not requires a 'leap of faith' I would guess.

My personal issue with attributing observations to additional dimensions, is that additional dimensions can describe pretty much anything and so they become a catchall for unexplained observations.
Perhaps it is because I fail to fully comprehend the physics involved in M-theory, but it seems a little too left-field for me. I'm yet to be convinced

[Mr Whippy]

Atomic12C said:

This is the concept of taking a 1-D point and stretching it to a 2-D line. Then taking 2-D lines to form a 3-D shape which now has a property of volume.
Then the trick is to take that 3-D volume and stretch that in to a 4-D entity.... and so on. (Hyper-cubes etc.)


So additional dimensions are concepts that fit in to theories which then have proved quite successful in describing observations.
Whether additional dimensions are 'real' or not requires a 'leap of faith' I would guess.

Like the characters in Flatland, no leaps of faith are required to conceptualise 1d for the 1d'ers, or 2d for the 2d'ers, and so on.
Just because we're stuck with perceiving 3 dimensions in a spatial manner and being unable to extrude a 4th, doesn't make it unlikely there are 4 or even 11 dimensions.


This is the same stance that leaves people saying we're in the Goldilocks zone for life on a planet, yes, the very life that exists on planets in this zone which we're a part of, so by definition exist in it, and observe it.

No doubt there are intelligences on methane worlds where liquid, gas and ice can exist all at once, with chemistries beyond our understanding, saying how they're in the Goldilocks zone for life, and how amazing it is that their world occupies such a location.

The point is, we mentally visualise the universe spatially and using 3 dimensions because that's just us.

That doesn't mean the universe isn't 11 dimensions and to some other observer it's not seen as 5 of the different dimensions and they're all seen as colours on a '1d point' but to them that makes complete sense.


Just as we 'see' in colour, and colourise images of xrays and gamma rays, we're trying to 'spatialise' the universe.
It's not going to be effective at conveying the reality.

[Atomic12C]

Mr Whippy said:

The point is, we mentally visualise the universe spatially and using 3 dimensions because that's just us.

That doesn't mean the universe isn't 11 dimensions ...

True.
Or 15 dimensions, or 99 dimensions etc. etc.

However without fully being able to apply the scientific method (in terms of observations)* to string (M) theory, it is by definition a philosophical approach. But that again is not a negative statement against the theory or the possible existence of 11 (or more dimensions).
If M-theory it is able to predict against observations then it is valid. If its able to predict results and solve equations in the language of maths that also fit observations then again its valid.

The only issue is, that as we are unable to 'know' what is actually happening on such minute levels, we are left to just philosophize on it. The same applies to many aspects of quantum mechanics to be fair. Many particles have been observed via collision decay paths at CERN for example, but there are still aspects of quantum mechanics that will never likely be observed.

Without observation/measurement those aspects are by definition "philosophy", or as some like to put it "a leap of faith", if they really want to believe they exist.


-* observations of strings is never going to be a possibility, there is nothing that we would ever be able to use to 'shoot' at them or 'scan' them to observe such minute vibrations of looped 11-dimensional energy. (Not yet anyways - until we possibly are able to utilise other dimensions to produce observations in our 4-D 'world')

[AshVX220]

I thought that time had been decided to be the 4th dimension?

[Atomic12C]

AshVX220 said:

I thought that time had been decided to be the 4th dimension?

Yes generally in physics the 4th dimension is time.

However if you take the maths approach when exploring geometry, the 4th dimension can be an extrusion of volume.
Just as volume is an extrusion of a 2D shape in to a 3D object, a 4D "object" can be an extrusion of a 3D object.

[Prof Prolapse]

I think saying "philosophy" is quite a generous way of saying "it isn't a scientific theory" personally.

[Atomic12C]

Prof Prolapse said:

I think saying "philosophy" is quite a generous way of saying "it isn't a scientific theory" personally.

Any theory though is a practitioner of philosophy

[Prof Prolapse]

Atomic12C said:

Prof Prolapse said:

I think saying "philosophy" is quite a generous way of saying "it isn't a scientific theory" personally.

Any theory though is a practitioner of philosophy

In the same way that any person is an Ape, but not every Ape is a person perhaps.