Questions of the universe and it's beginning...

[nikkixsugar]

A while ago, I was thinking about the universe. "How can it be infinite?" and "How can it not be infinite?" because in my education I was taught that the universe was EVERYTHING. My question 1 to you is: "What is outside of the universe?"

The other question is, "If energy cannot be created or destroyed, how can energy have always been there if in the beginning, there was nothing [quoting the bible not intended ]?"

[curiosityandthecat]

An "actual" infinite can't really exist. A theoretical infinite, sure. Anything that has a beginning is not infinite, as per the definition of infinite. Something infinite must always have been, and always be. Part of this problem is our rather pedestrian concept of time. Time is really just a measure of decay. If there is nothing decaying, there is no time. "Before" or "outside" the universe isn't really a concept worth wrapping your head around, as we can't think outside time, and before or outside our physical universe time wouldn't be an issue.

And there wasn't "nothing" in the beginning.  :cool:

[nikkixsugar]

An "actual" infinite can't really exist. A theoretical infinite, sure. Anything that has a beginning is not infinite, as per the definition of infinite. Something infinite must always have been, and always be. Part of this problem is our rather pedestrian concept of time. Time is really just a measure of decay. If there is nothing decaying, there is no time. "Before" or "outside" the universe isn't really a concept worth wrapping your head around, as we can't think outside time, and before or outside our physical universe time wouldn't be an issue.

And there wasn't "nothing" in the beginning.  :cool:

thanks  

[leftyguitarjoe]

Ah, you see, the universe might as well be considered infinite, as it is always expanding.

As far as we know, the universe in unbounded. There is no detectable edge or wall, so its safe to assume that its infinite.

OUTSIDE of the universe, as far as we know, there is nothing. There is less than nothing. there is no reality or existence. There are several multiverse theories brewing, but no substantial evidence to support them.


Now for you energy question. You stated the law that is "Conservation of Energy". Before the big bang, everything you see now WAS there. It was just condensed into an unfathomably dense speck. You see, energy and mass can be "converted" using the famous equation E=mc^2, whereas E = energy, m = mass, and c = the speed of light in a vacuum, about 186,000 miles per second. That is saying ANYWHERE there is energy, it can be converted into mass and vise versa. In the universe before the big bang, there was mass, so, in turn, there was also energy.

How can this be? WELL, you have to delve into string theory. I've read several book on the subject, and to many of you, any explanation I could give might as well be in chinese.

[Loffler]

The current understanding of the universe is that it's not infinite; in fact, cosmologists give it an estimated size -- 93 billion light years across.

However, they also postulate that space itself has a shape. It might be "flat," as is the layman understanding of space, but it might also be curved, meaning it has a property wherein you could depart Earth in any direction into the cosmos and continue in that direction... and eventually arrive back at Earth.

[leftyguitarjoe]

but it might also be curved, meaning it has a property wherein you could depart Earth in any direction into the cosmos and continue in that direction... and eventually arrive back at Earth.

that is the same explanation I know, and it might as well be infinite IMO

[Loffler]

but it might also be curved, meaning it has a property wherein you could depart Earth in any direction into the cosmos and continue in that direction... and eventually arrive back at Earth.

that is the same explanation I know, and it might as well be infinite IMO

It would resemble infinity in some ways and in some ways not. For example, as with an infinite universe it would be possible to go any direction forever. On the other hand, it would not be possible to completely fill an infinite universe, whereas a "looping" universe has a limit.

[leftyguitarjoe]

If the observable universe is smaller than the entire universe (in some models it is many orders of magnitude smaller), one cannot determine the global structure by observation: one is limited to a small patch. Conversely, if the observable universe encompasses the entire universe, one can determine the global structure by observation. Further, the universe could be small in some dimension and not in others (like a cylinder): if a small closed loop exists, one would see multiple images of objects in the sky.

^ I jacked that from wikipedia, but it sums up why I doubt any measurements we have taken thus far.

[Loffler]

If the observable universe is smaller than the entire universe (in some models it is many orders of magnitude smaller), one cannot determine the global structure by observation: one is limited to a small patch. Conversely, if the observable universe encompasses the entire universe, one can determine the global structure by observation. Further, the universe could be small in some dimension and not in others (like a cylinder): if a small closed loop exists, one would see multiple images of objects in the sky.

^ I jacked that from wikipedia, but it sums up why I doubt any measurements we have taken thus far.

Maybe we do see multiple images of objects in the sky. What appear to be two galaxies to a telescope might be the front and back of a single galaxy on opposite ends of the sky.

[nikkixsugar]

The current understanding of the universe is that it's not infinite; in fact, cosmologists give it an estimated size -- 93 billion light years across.

However, they also postulate that space itself has a shape. It might be "flat," as is the layman understanding of space, but it might also be curved, meaning it has a property wherein you could depart Earth in any direction into the cosmos and continue in that direction... and eventually arrive back at Earth.

I knew it wasn't infinite. I believe current estimations are at 156 billion lightyears across. http://www.space.com/scienceastronomy/mystery_monday_040524.html

[Perillux]

Someone else actually posted on this forum something that might interest you:
viewtopic.php?f=6&t=1688

It shows how basically everything, even in existence today as we know it basically is "nothing".  But in a more 'stable' form of nothing.

[Promethium147]

WOWSERS there are misconceptions here, but they are very understandable - the newest astrophysical info is coming hard and fast, you know.

Our Universe is 57 to 58 billion light years in diameter. It has a visible edge that's ABOUT (due to the expansion of space itself) 380,000 light years closer; as the cosmic fireball expanded initially, it was opaque, and became transparent at approx. 380,000 years.

This is seen as a map of the cosmic background radiation. The map actually represents the surface of the fireball - inverted, and visible in every direction. We thus appear to be in the precise center of a Universe that explodes at the speed of light, while space expands - and we still do, no matter where in the Universe we are. The Background Rad sphere is not uniform, tho, and actually appears to have "poles". This cosmological problem has been dubbed - most amusingly - the Axis of Evil. It has to do with the initial quantum fluctuation.

The Old School model, which still applies, is a fourth dimension above our apparent three. Since our brains did not evolve to visualize this, it is much easier to dumb it down, and imagine ourselves as two-dimensional Flatlanders living on the surface of a vast three-dimensional sphere, such that the curvature of the sphere is so slight on our scale as to be imperceptible.

The 3D sphere has similar curvature everywhere ya go. You relationship to it does not appear to change - only the local environment.

The Standard Model of Physics maps the evolution of the Universe not quite back to the beginning, we still don't understand the initial Plank Epoch - which was a whole 5.4 x 10 to the negative 43 seconds in length. This is the smallest possible division of time - a quanta of time. Time is quite finite in both scalar directions.

There are five major overriding eras in our model of the Universe, and we are at the very beginning of the second. The next is all black holes. The final one is nothing more than very, very low energy photons, and finally - the death of time itself. But long before that, time as we "know" it essentially has no meaning.

Gosh, I could go on all day, but there is just too much. Suffice to say, there's plenty o' room to stretch the legs.

There are endless Physics and Astrophysics resources on the Web. Wikipedia alone has more than a man may swallow, and even has open-source textbooks of every sort. Chow Down!  

[Promethium147]

Stepped right in it, I did.

The estimated diameter of the Universe I mentioned was made not long ago from the same data (but now there is more) with some certainty, and was valid only recently.

But as I said - things change fast in this area of study - that's what makes it fun!  

[monkeyNutBread]

Interesting stuff, though I doubt that I understood all of it. Promethium's post about curvature makes me wonder what it would be like if you were on a planet that was very small... would you be able notice the curvature, or would such a planet not possess the gravity to hold you down? I think I've been playing too much Mario Galaxy.