[DoctorBeaver]

No.

[LeeE]

Ice-cream - yummy []

[Soul Surfer]

LeeE you seem to be accidentally or deliberately misunderstanding what I am saying.  Your original question concerned how the fundamental laws of an understandable universe would vary as a function of the number of extended dimensions that the universe occupied.  I have been trying to explain to you the answer to this question.

[LeeE]

Any misunderstandings on my part are accidental - I'm certainly not trying to wind anyone up.  Umm... I haven't asked any questions, except rhetorical ones - I think?  Made quite a few statements, but no questions that I recall.

NeilP asked the original question, regarding the need for time to exist before the Big-Bang.

I think our discussion started when you said:

Interesting points and I see they could be very relevant but having three spatial dimensions is important for a long lived universe.  The reason for this that long range energy fields follow an inverse square law and the only law that allows long term stable orbits to form is an inverse square law.

...and that's when I said:

...but having three spatial dimensions is important for a long lived universe

But isn't that just saying that a universe with a different number of spatial dimensions has to have different laws?

Also, don't just think down to < 3 spatial dimensions - you've got to think up to > 3 as well.

The problem I have with some of what you say is that, for example, citing the need for inverse-square laws presupposes that energy has the same structure and form in less than or greater than 4D space-times, which seems impossible to me.  If the energy is different to energy as we know it, it will be unlikely to be governed by the same laws that we know.

Let's say that energy in 5D space-time looks like a 3D solid to us (entirely debatable, of course) - how then, does the inverse-square law work with a solid?  Is a 4D solid in 5D space-time still convertible to energy according to e=mc^2?

[DoctorBeaver]

LeeE - it is possible that elementary particles exist in more than 3 spatial dimensions (string theory, for instance). Therefore, your question "Is a 4D solid in 5D space-time still convertible to energy according to e=mc^2?" is irrelevant.

[Soul Surfer]

One of the fundamental requirements of an understandable universe is to have physical laws that are not dependant on (time, see below) your position or your orientation (in an empty universe).  This implies that the universe obeys the conservation of energy and the conservation of angular momentum. This in turn implies that as the energy spreads out in three dimensions the surface area depends on the square of the distance form the source. therefore fields follow an inverse square law.  In fact in a general understandable universe with n dimensions the energy law is an inverse n-1 law.

These are totally fundamental requirements and independent of most of the detailed physical laws.

[JP]

Just to correct you slightly, Soul Surfer, independence of physical laws on time gets you conservation of energy, while independence on position gets you conservation of momentum. 

[Soul Surfer]

Obviously. I forgot to state that. Thanks for the correction.

[LeeE]

DoctorBeaver:  only possibly irrelevant, I think  []

[LeeE]

SoulSurfer:  Key word

understandable

You still seem to be arguing that the only valid laws are the ones that apply to 4D space-time, which naturally apply to 4D space-time, and which don't apply to non-4D space-times.

Otherwise, I surrender.

[Soul Surfer]

No what I was saying applies to a universe with any number of spatial and temporal dimensions the only requirement is that the physical laws do not change abruptly an arbitrarily dependant on precisely where you are in it in the absence of any causes for this. Such a universe would not be understandable.  Ie we are talking about basically causal universes.  I presume that you are prepared to accept this whatefer your personal theories are because if you dont you can say absolutely nothing about the universe and it blatently does not apply to the universe we are in where physical laws are obeyed very precisely.

[yor_on]

I enjoy reading you all
Cool thoughts from creative minds.

To me time is a very strange thing.
I really enjoyed thelastman's thoughts though.
critical-point transitions was a nice description.

and even though we can't say what preceeded 'time' there must have been 'something'.
Or else all math we use is fundamentally wrong.
That from zero comes zero.

Some people likes to see time as 'event' based.
Checking out how time seems to move in QM that might be attractive.
Feynman's diagrams allows for time to move both forward and backward if I have it right.
But to be 'event' based there seem to be implied something 'in between'?
Also no experiment done that I know of have proved time anything else but a 'flow'.

So to my eyes time is a flow with an arrow macroscopically.
But I'm open for ideas and experiments:)
 

[Soul Surfer]

The fundamental properties of this universe are the conservation of energy and angular momentum with a four dimensional space-time and hints that suggest some more "dimensions" may also exist this implies that the universe has always existed in one form or another it's just that we havent got the full model right yet.

I have some ideas that are worth thinking about but they are best placed on the new theories board.  Ihave already posted some under the subject heading of "evolutionary cosmology"  but it might be an idea to start a new topic

[lyner]

The word Shiboleth seems to apply to the way people include 'time' in a sentence. They can't seem to discuss time without talking in terms of time itself. You shouldn't have to use words like 'before', which is a temporal description and  carries baggage with it which can cloud the issue. The whole question has to be discussed as if we were looking at it from 'outside' time.
Discontinuities may not be aesthetically pleasing but you can't discount them without very good reason. Gut feelings about time don't count any more than gut feelings about God when you're trying to be scientific.
If time is regarded as partly Scalar, unlike the other familiar dimensions which have magnitude and direction, then you can accept only 'magnitude' without getting upset about the lack of negative values.
Would we be having the same problem with Negative Entropy (I.e. Beyond total orderdness) ?

[Mr. Scientist]

Dear H G Wells-ologists,

See my clock ?


 [ Invalid Attachment ]

Nice eh ?

No need to ask ewe what time I took that photo ?


Could time have existed " before " the big bang ?..if not why not ?...also..would ' time ' have had to be created just before the big bang so that the big bang would have something to explode into ?...do ewe know what I mean ?..In that ' Time ' is the medium that allowed the big bang to bang !! ?.


Thank ewe for your kind consideration in this matter.

mwah mwah mwah



Neil
Confused About Time
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No, time couldn't have existed before big bang, because then space would have had to have existed, since space and time are a single entity.

[Mr. Scientist]

As for the 'totality' thing, I think this is something to do with the definition of  'universe' in the first place. If we define the Universe as everything that we have a chance of experiencing then there could well be much much more.

There is no outside to the universe, according to relativity.

[DoctorBeaver]

As for the 'totality' thing, I think this is something to do with the definition of  'universe' in the first place. If we define the Universe as everything that we have a chance of experiencing then there could well be much much more.

There is no outside to the universe, according to relativity.

But we know that relativity isn't the last word.

[Mr. Scientist]

As for the 'totality' thing, I think this is something to do with the definition of  'universe' in the first place. If we define the Universe as everything that we have a chance of experiencing then there could well be much much more.

There is no outside to the universe, according to relativity.

But we know that relativity isn't the last word.

Well, not just relativity. Also every known theory concerning such a subject.

[DoctorBeaver]

It depends how you define universe. If you define it as everything that exists, then your statement is correct. However, it could be taken to mean just our universe in which case there could be a higher dimensional bulk outside of it.

[Mr. Scientist]

It depends how you define universe. If you define it as everything that exists, then your statement is correct. However, it could be taken to mean just our universe in which case there could be a higher dimensional bulk outside of it.

You do mean string theory don't you(?), where possibly our universe is floating around in a multidimensional swimming pool...

...i hate string theory. I think its a waste of time.