amateur observations

growler

i'm a bit of a reader of trash physics / science books, the likes of Hawking and Brian Greene, and there are a few things that I can't reconcile very well with my ,albeit limited, understanding of how it all works, bear with me and some insight would be appreciated.

1 The theory of a multi-dimensional universe, while the math may fit, seems too unusual an answer given eveything we know of nature, particularly I find the calabi-yau shape to be at odds with what we know of the universe. Would not a double-helix, snowflake, or extrapolation of a known 3 dimensional shape be more likely than the proposed theoy of a calabi-yau shape ? ( is there a 3 dim. equivalent of the calabi-yau shape? )

2. Dark energy / matter: if we know gravity can be both attractive and repulsive as a force, is it not potentially viable that the reason we cannot observe / measure / understand the dark stuff is because dark matter/ energy is repulsed by normal matter / energy making it always beyond those of us who exist in the reality of non-dark matter / energy? Would the inability of dark / non-dark worlds to interact (rather than exist) in the same "space" not help explain why they are not found side by side, as well as provide some continuing impetus to an expanding universe ?

of course its quite likley that I don't understand what i read.

Chucky

Hey, I have only read Hawkins' A Brief History of Time and am very puzzled by the concept of a multi-dimensional universe too. I just don't think it makes sense. The way I like to think of it is that all those years ago there were actually various big-bangs but they each still hold the same laws of all the sciences that we have developed. Perhaps these singularities were so far apart that light from each hasn't reached each other yet.


About the missing (and as yet undetectable) dark matter: Well, perhaps we just haven't developed the correct instruments to detect it yet. Perhaps the vacuum of space isn't a vacuum as defined by science after all? It would be very arrogant of us to assume that we have discovered every form of energy in the universe.


On the other hand, maybe there is a flaw in our maths somehwere along the way and we have actually discovered every form of energy. If that is the case then maybe we will someday think that we have discovered something that isn't actually there at all. And, if that happens, then our maths would become further incorrect.

Son Goku

growler wrote:

1 The theory of a multi-dimensional universe, while the math may fit, seems too unusual an answer given eveything we know of nature, particularly I find the calabi-yau shape to be at odds with what we know of the universe. Would not a double-helix, snowflake, or extrapolation of a known 3 dimensional shape be more likely than the proposed theoy of a calabi-yau shape ? ( is there a 3 dim. equivalent of the calabi-yau shape? )

The calabi-yau shape is required in String Theory to make probabilities consistent and unitary, while still keeping compactification, it is a purely mathematical requirement.

Dark energy / matter: if we know gravity can be both attractive and repulsive as a force, is it not potentially viable that the reason we cannot observe / measure / understand the dark stuff is because dark matter/ energy is repulsed by normal matter / energy making it always beyond those of us who exist in the reality of non-dark matter / energy? Would the inability of dark / non-dark worlds to interact (rather than exist) in the same "space" not help explain why they are not found side by side, as well as provide some continuing impetus to an expanding universe ?

Dark energy was predicted by Einstein over 80 years ago. It comes from the cosmological constant in the Field Equation. The point is we don't understand the field which generates this value.

growler

Chucky wrote:

. Perhaps the vacuum of space isn't a vacuum as defined by science after all? It would be very arrogant of us to assume that we have discovered every form of energy in the universe.

.

As far as I understand it the "vacuum" isn't a vacuum at all as it, like everything / everywhere/ when, is full of a "Higgs Ocean".



Another thought occured to me when reading about the theoretical concepts of wormholes in time travel. The argument is that logic would prevent one travelling back through spacetime in your own dimension in order to avoid potential paradoxes, makes sense, but given the uncertainty principles inherent in quantum theory, would it not be conceivable that either (a) uncertainty would create a theoretical possibility of travel to one's own dimension ? or that (b) once we had acquired the knowledge to create aand direct a wormhole, we would also likely understand the quantum mechanics necessary to specify what dimension it pointed to ?

The idea that human inspired logic would preclude a possibility in such a complex issue seems a bit,well, vain.

Son Goku

It is in fact quantum mechanical effects that prevent time travel.
Specifically Quantum Field Thoery effects.