What is beyond the boundaries of our visible universe?

[Dragon Star]

He did have some very good questions, it took me a while to ponder on them for an answer on a few.

[dmill1220]

Hi Dragon!
thanks for the quick and excellent response!
but here is were you lost me!
Quoteark Energy can't have any significant effect on the length of a photon wave, even on large scales. Something that we can't even detect likely isn't going to affect matter much in any way
end Quote:
it does effect matter! we see its efffects on matter such as the speed of stars around Galaxies they are not as slow as they should be.
isnt that how we found it?
Dennis

[Dragon Star]

Oh, sorry, that was a bit misleading, what I mean is to detect it in the lab, as direct physical proof, not by direct observation.

Sorry.

[dmill1220]

A most interesting Dilema this dark energy question.
I am totally fascinated by its implications and what we might uncover!
Thanks!
Dennis

[Dragon Star]

Sure.

BTW, if at any time any of you don't understand what I say or what direction I am taking a conversation, step up and ask such as Dennis did, not only does it help you to understand, it helps me and everyone that is reading including those just browsing the forum. Treat me with this respect and I will do the same for you to make this a better place of knowledge for people of all ages to enjoy.

Any more comments, questions, or general statements to add?

[dmill1220]

Yep!
Very well said! and I enjoyed this conversation extremely!
You have Enlightened me in a very Impressive and respectful manner.
I am sure I will like it here very much!
Dennis

[pranab]

HOw the dark Energy model of Universe can be explained in the most popular Existing Scalar field Model?. We think that the Scalar feild model is not suitable for dark energy...... "The stress tensor for tachyonic scalar feild model to make the vaccum energy variable with time] will allow a variety of models with time dependent cosmological constant and probably will not help to understand dark energy at any deeper level because scalar feild model requires a suitable designer to architect such models of universe. These models are non predictive and degenerate, we need to assume the cosmological constant zero and the difference between cosmological constant and scalar feild model varies with time. If we assume that dark energy in universe is due to a cosmological constant then such universe will be asytotically de sitter universe at late epoch. Such a universe will have* spend most of time in a de- sitter phase which is time translation invarient- The first de-sitter phase corrospond to inflation and second composed to acclerated expansion arising from cosmological constant....." Taken a part from The Current Science-2005
Dr Pranab Kr Bhattacharya
Mr Rupak Bhattacharya
Mr Ritwik Bhattacharya
Mrs Dahlia Mukherjee
www.unipathoscom

[dmill1220]

Dr. Pranab
Please excuse my inability to understand completely what you have just said!
Could you rephrase that in more of a laymans term?
De sitter phase ?
Scalar Field Models?
I think I understand what you're trying to say but im not so sure!
Dennis :}

[Dragon Star]

Oh boy...what have you done. That is one big can of worms...

Originally Posted by pranab

HOw the dark Energy model of Universe can be explained in the most popular Existing Scalar field Model? We think that the Scalar feild model is not suitable for dark energy...... "The stress tensor for tachyonic scalar feild model to make the vaccum energy variable with time] will allow a variety of models with time dependent cosmological constant and probably will not help to understand dark energy at any deeper level because scalar feild model requires a suitable designer to architect such models of universe. These models are non predictive and degenerate, we need to assume the cosmological constant zero and the difference between cosmological constant and scalar feild model varies with time.

First of all, Scalar Field Theory is pseudoscience. Keep this in mind.

SFT states that there is a basic mechanism that produces the electric field and the magnetic field, and states that electromagnetism isn't completely described by the standard electromagnetic theory.

If we assume that dark energy in universe is due to a cosmological constant then such universe will be asytotically de sitter universe at late epoch. Such a universe will have* spend most of time in a de- sitter phase which is time translation invarient- The first de-sitter phase corrospond to inflation and second composed to acclerated expansion arising from cosmological constant....." Taken a part from The Current Science-2005

About De Sitter, a De Sitter Universe is one with no ordinary matter content but with a positive, increasing cosmological constant. This becomes exponential until expansion is so fast that physical distance between any two non-accelerating observers will eventually be growing faster than the speed of light. At this point those two observers will no longer be able to make contact. Therefore any observer in a De Sitter universe would see event horizons beyond which that observer can never see nor learn any information.

Then you have De Sitter Space, which most easily defined as a sub-manifold of Minkowski space in one higher dimension. In general relativity, De Sitter space is the maximally symmetric, vacuum solution of Einstein's field equation with a positive cosmological constant... Translation: I don't know. Something I haven't studied at all. But it seems to not pertain to this at the moment.

That said, pranab's quote must be describing De Sitter Space, as De Sitter Universe won't happen for us until the universe reaches the infinite future (if it continues to expand as it is). So if you ask me the entire idea in the quote is screwed up as it specifically describes "De Sitter Universe", which is physically impossible right now and in the past.

All well, I took a poke and my brain hurts, so I'm done.

[dmill1220]

Thanks Dragon!
I totaly understand now, what he meant and, what I did!
Dennis:}