General Relativity.

Why? -because there it is you leave evidence, and must resort to speculation, and assumptions, etc. which are not provable.

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I find it interesting when people would rather say..."here be dragons." when the limits of they're knowlege is reached.
And to answer your questions. The universe is infinite according to recent obervations made by NASA.

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Guess it depends how you fefine what is the dragons there, since whatever it is exists somewhere other than a place you could offer evidnece. Now, thanks for the tidbit they think the universe is infinite. What tipped the balance there, and made it an official guess?This message has been edited by simple, 10-11-2005 05:39 PM

What tipped the scales...? Data from WMAP. The universe seems to be at a critical density.
WMAP Site Help Page Error

The link doesn't work, but anyway, critical density does not necessarily imply an infinte universe. One of the major points of inflation is that it produces a critical universe from a non-critical universe. After inflation, both a closed and an open FRW will look flat and critical. It's a nice answer to an otherwise problematic fine-tuning question.

So, again, it ain't neccesarily so! Amazing. At least it is admitted. Should they tack 'philosophy' onto that field? Something like theoretical philosophical physics!?

That link was broken, but at the site I found this.
"Is the Universe Infinite?The shape of the universe is determined by a struggle between the momentum of expansion and the pull of gravity. The rate of expansion is expressed by the Hubble Constant, Ho, while the strength of gravity depends on the density and pressure of the matter in the universe. If the pressure of the matter is low, as is the case with most forms of matter we know of, then the fate of the universe is governed by the density. If the density of the universe is less than the "critical density" which is proportional to the square of the Hubble constant, then the universe will expand forever. If the density of the universe is greater than the "critical density", then gravity will eventually win and the universe will collapse back on itself, the so called "Big Crunch". However, the results of the WMAP mission and observations of distant supernova have suggested that the expansion of the universe is actually accelerating which implies the existence of a form of matter with a strong negative pressure, such as the cosmological constant. This strange form of matter is also sometimes referred to as the "dark energy". If dark energy in fact plays a significant role in the evolution of the universe, then in all likelihood the universe will continue to expand forever."
WMAP Cosmology 101: Shape of the UniverseNow an acceleration to some may suggest or imply dark matter, because they need something to fit the bill here, and physical unseen matter was all they could come up with. Also, as the article nted, ominously called, 'dark energy'. I'm not allowed to speculate on this forum at something else one might call light energy, so I won't. Funny how some reserve the unknown for themselves, and their beliefs, and own suggestions!Beyond this, they can't seem to say whether it will go on forever, or collapse! Either way, the exercise there in supposition, and guessing at the unknown is a closed church!I'll have to satisfy myself here, not with easily overcoming opposing thoughts to my own with better reason, but with listening to the tall tales of our unknown fate, which I find amusing enough for now.

simpleI do not know if you have Adobe Reader installed or not but if you do download this article from http://www.fccps.k12.va.us/...En...2_5_Energy_Intro_1098.pdf - 21 KBIt is from the feynman lectures on physics and may well help you to get a better understanding. Let me know either way.

Thanks for that. Link is broken, though.

simpleTry this one http://www.fccps.k12.va.us/...Work/2_5_Energy_Intro_1098.pdf

If I am just standing as I have described, and know with certainty (by infinitely precise measurement) that there is, say, 30 light years of (as perfectly as possible) flat space in one direction to a point A. At 90 degrees to this there is 40 light years of flat space to a point B. Am I not justified, conventionally, in believing that there is 50 light years of flat space in a straight line between these two points assuming no curvature between?If there were curvature between these two points, would there no longer appear to be 30 ly of flat space in direction A and 40 ly of flat space in direction B? I would further assume that perhaps the angle between the two points from my vantage point would no longer appear to be 90 degrees. Would this curvature between the two points A and B alter my perception of the position of these two points A and B so that they wouldn't appear as they would have had there been no immense mass between them?I hope I haven't blurred my intent here, but can curvature in one area of otherwise flat space alter the perception of distant objects within said flat space so that you wouldn't perceive the 90 degree angle to begin with?

Yes It depends. It could be either, depending on the nature and extent of the curavture. Same as above. Yes, it can.If you make your mass a cosmic string, aligned normal to your AOB plane, then you have a situation where all of space is flat apart from at the string. The effect of the string is to introduce an angle deficit, such that there are less than 360 degrees around the string. Thus you can still have A and B appearing at 90 degrees and at the declared distances, but the line AB will certainly not be the pythagorean distance, nor the angles OAB and OBA the expected trignometric values.This message has been edited by cavediver, 10-12-2005 01:03 PM

Thanks for the link,
"It is important to realize that in Physics today, we have no
knowledge of what energy is."
I think that is important, to realize we don't know everything.

simpleOf course we do not know everything but we are hardly clueless.

Hardly clueless is a comparitive concept. If there was a whole lot more than the physical universe, and we hardly have a grip on what's going on here, that would be comparitively clueless. If not, and the unknowns that abound are really just around the corner, if we follow the carrot on the stick, then, it is true, we have some good clues now, after all. But which of these best applies, we really don't know, and indeed, in that respect are clueless indeed.

"Our knowledge is imperfect; thus, the things I make believe are true."Does that sound like an airtight argument to anyone? Not me.

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"Our knowledge is imperfect; thus, the things I make believe are true."
Does that sound like an airtight argument to anyone? Not me.

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Well, if make believe erronous arguements are to be shunned, then we need to look at some of the cosmological whoppers! Not the things we do know, but those other things, like how we came from nothing. Or where we are heading, hey, they don't know! Are we in an infinite universe? 'gee we kinda think so, but maybe not'. Those with imperfect knowledge should stick to what they know, and not get to preaching alternate creation.