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Vibecrewangel · #1

Wrap your brains around this......

Can we find a center to the Big Bang by looking at how distant quasars are moving?

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No. The universe is expanding in a way that is consistent with it having no unique center in 3-dimensional space. Every point in space was the 'center' of the Big Bang, and since then, space has been continuously dilating as time has gone on. The motions of the distant quasars, and the light from the Big Bang itself show no unique center in space.

Zero Signal · #2

The center of the Universe does not exist in three dimensional space.

For years I have always thought of the universe as a hypersphere; a four dimensional sphere (there are more dimensions but let us keep this simple). The center of the universe would not in any way be accessible to us in the three dimensions that we are confined in.

A visual point to make is representing the universe as a balloon with dots drawn on it. As it expands, every dot appears to be moving away from each other, from their own frame of reference. Thus, any point in the universe in our three dimensions would appear to be the center of everything, because in our frame of reference everything is moving away from us.

This brings up another issue. As on the surface of the Earth, if you travel in a straight line long enough you will eventually come back to where you started. Interestingly, this becomes apparently equally applicable to the universe. It would take much, much longer, however, given the expansion of the universe since it is adding to the distance you would need to travel all of the time.

In short, if you want to find the center of the universe, and indeed the origin of the Big Bang, then look around you; it is everywhere.

AChimp · #3

I seem to recall reading about one physicist's theory that if you were to travel in a massive circle around the universe at the speed of light, you could travel through time, depending on the size of the circle. I think he was disproven, though. :/

Another interesting point is that they don't think that the Universe will collapse anymore, but keep expanding and breaking down until it essentially burns out in several hundred billion years.

Vibecrewangel · #4

Zero - I beleive that only works if you use a closed system model. I know Hawkings uses that model, I think it's because it is the easiest to work with mathmatically.

I don't think the universe is a closed system, so the balloon example though valid, does not work for me.

Anonymous · #5

with the balloon example, the dots are on the outside of the balloon. So, there's no restriction, no 'closed system' that the balloon itself is in.

AChimp · #6

You are forgetting that the entire Universe is the ultimate closed system. You can't get any more open than that because nothing exists outside of it.

Vibecrewangel · #7

Chojin and Chimp - Open / Closed / Flat
These different descriptions concern the future of the Universe,
particularly whether it will continue to expand forever. The future
of the Universe hinges upon its density---the denser the Universe is,
the more powerful gravity is. If the Universe is sufficiently dense,
at some point in the (distant) future, the Universe will cease to
expand and begin to contract. This is termed a "closed" Universe. In
this case the Universe is also finite in size, though unbounded. (Its
geometry is, in fact, similar to the *surface* of a sphere. One can
walk an infinite distance on a sphere's surface, yet the surface of a
sphere clearly has a finite area.)

If the Universe is not sufficiently dense, then the expansion will
continue forever. This is termed an "open" Universe. One often hears
that such a Universe is also infinite in spatial extent. This is
possibly true; recent research suggests that it may be possible for
the Universe to have a finite volume, yet expand forever.

One can also imagine a Universe in which gravity and the expansion are
exactly equal. The Universe stops expanding only after an infinite
amount of time. This Universe is also (possibly) infinite in spatial
extent and is termed a "flat" Universe, because the sum of the
interior angles of a triangle sum to 180 degrees---just like in the
plane or "flat" geometry one learns in (US) high school. For an open
Universe, the geometry is negatively curved so that the sum of the
interior angles of a triangle is less than 180 degrees; in a closed
Universe, the geometry is positively curved and the sum of the
interior angles of a triangle is more than 180 degrees.

The critical density that separates an open Universe from a closed
Universe is 1.0E-29 g/cm^3. (This is an average density; there are
clearly places in the Universe more dense than this, e.g., you, the
reader with a density of about 1 g/cm^3, but this density is to be
interpreted as the density if all matter were spread uniformly
throughout the Universe.) Current observational data are able to
account for about 10--30% of this value, suggesting that the Universe
is open. However, motivated by inflationary theory, many theorists
predict that the actual density in the Universe is essentially equal
to the critical density and that observers have not yet found all of
the matter in the Universe.

AChimp · #8

Yeah, that's fairly interesting, Vibe. It raises the point of dark matter at the end. I think that they estimate that 90% of the universe is probably made up of it, and the don't really know what kind of effect that it would have on the density of the universe, or even what kind of properties it has.

Zero Signal · #9

The balloon example was a simplification for visualizing a hypersphere. Also, whether the dots are on the outside or not is irrelevant. The balloon's surface is just representative of a plane describing our three dimensions in relation to the other multiple dimensions.

I agree with AChimp. The Universe is a closed system by virtue that it is expanding, meaning that it must have defined boundaries (although they exist only in the extra dimensions; 10 or 26 depending). Finite, but unbounded, as it were.

I am not so sure that nothing exists outside of our Universe, at least nothing that we have a frame of reference for relating to it. Elaborating, I remember reading about infinite regression regarding the Universe and other universes. As if an electron (for example) was a closed system like our Universe, we would have no concept of what was outside of it, but outside of it, it may be just a fundamental part of an even larger universe. Likewise, going the other direction, a simple electron could hold within it an entire universe like our own. Or not like our own.

Using the electron is simply a conceptualization of the idea, of course.

AChimp · #10

WHAT IF OUR UNIVERSE IS AN EXPERIMENT IN AN ALIEN LAB AND THEY WANT TO DEACTIVATE US?!

Zero Signal · #11

Vibe: Thanks for reminding me. I do remember reading about those. I believe the open system would be shaped something like a saddle; a hyperbole, I think.

Chimp: There is also dark energy in addition to dark matter, theorectically. Gravity holds things together at the local frame of reference for galaxies (and also between this in clusters of galaxies), however, some type of force stretches across the entire Universe to pull it apart.

As the theory goes now, dark energy comprises 65% of the Universe, dark matter is 30% and actual matter is a measly 5%.

While on the subject of Universe expansion there is also the two ideas of either galaxies becoming frozen in time, or, that time never ends.

Zero Signal · #12

Quote:

Originally Posted by AChimp

WHAT IF OUR UNIVERSE IS AN EXPERIMENT IN AN ALIEN LAB AND THEY WANT TO DEACTIVATE US?!

Fortunately, there are few forces in the Universe strong enough to rip an electron apart.

AChimp · #13

Quote:

I believe the open system would be shaped something like a saddle; a hyperbole, I think.

The layman's example that I've heard is a Pringle. I think Hawking used that one himself since most people don't know what hyperboles look like.

Zero Signal · #14

As far as the galaxies being frozen in time, I am going to paraphrase what I read regarding it.

All of the distant galaxies are moving away from us, and at an accelerated rate. At this rate of acceleration, they will eventually begin receding at the speed of light, making it impossible for their light to be observed by us. In effect, the light cannot keep up with the Universe's rate of expansion. Intelligent life in galaxies with redshift of, I believe, 2 or more would not be able to send a signal to us because of this accelerated expansion.

The term "event horizon" is used also in this case to describe the point at which no further light can be received, as it is used in relation to black holes. 50 to 100 billion years is the calculated time frame, with those galaxies local to us and in out particular cluster will not be affected in our frame of reference. Then the light from the galaxies outside of our Local Group will evenutally fade away, as well.

Zhukov · #15

I don't think Stephen Hawking is as smart as we think he is. I think somebody just programed him.

Vibecrewangel · #16

Sorry...had to run off and work a finite amount of calories off of the infinite mass of my rump......

Zero, I think we are in a similar vein here. I do think that there are closed sytems within the infinite universe. Human exsistance and all we can perceive from our point of reference is most likely a closed system. Maybe using the word universe is the problem.....pehaps omniverse would be more appropriate (assuming that isn't already a "real" term)

Chimp, dark matter amuses me. As someone who prefers quantum physics/mechanics to regular physics/mechanics I love the fact that though physics gives firm hard calculations for things, it reffers to dark matter as something that can't be measured. In other words.....we can't find the missing mass, so either our calculations are completely wrong or mass is just a form of something else. It's why I think that the base substance of the infinite is pure energy.

The_voice_of_reason · #17

Quote:

Originally Posted by Vibecrewangel

I do think that there are closed sytems within the infinite universe. Human exsistance and all we can perceive from our point of reference is most likely a closed system. Maybe using the word universe is the problem.....pehaps omniverse would be more appropriate (assuming that isn't already a "real" term)

I personally don't see our universe as infinite, I see it as a finite shape that is surrounded by an infinite number of other universes. But since there is no "space" between them they are adjacent on at every point. I also see these infinite universes blossoming off of eachother, that is at every instant every particle jumps in a new direction causing a new big bang and creating a universe. This is allowed by quantum mechanics.

Vibecrewangel · #18

VoR - I can actually visualize that. It's really pretty. I have a fireworks video game where the object is to make sparks from one blast ignite others. It kinda looks like that in my head.

When I was a kid, and I mean like 5 or 6, I started pondering this. In my head I kept seeing a bubble inside of a bubble inside of a bubble.....always expanding outward so that each universe was inside of another universe. It was my simplistic way of trying to grasp infinity. Then one day someone showed me how to blow bubbles inside of bubbles. They become less round...have more edges. This changed my view drastically.

The_voice_of_reason · #19

I have a really philisophical question "why is it a universe and not an universe?"

Anonymous · #20

my grandfather wrote a book that he thinks disproves the big bang. or something.

Information Theory And Molecular Biology by Hubert P. Yockey
http://www.amazon.com/exec/obidos/tg...glance&s=books

i never read it, so i wouldn't know. but i think i remember it being about that.

mburbank · #21

Now you know there is more scienceing of proofs moreover to the creationist angle than there is upon the supposed called 'Big Bang'. But what Lib is going to say that?

I didn't think so.