The center of the Universe

[DarwinLied]

why are we assuming this universe isn't inside something right now? everything is in something right?

water in earth, earth in heliosphere, heliosphere in galaxy, galaxy in universe, universe in? I like to imagine it as a tiny bubble in an ocean of something. but even that would imply whatever hosts the universe would be in something else also.

what is on the opposite end of that planck length scale?

 

[orienteer]

1600 Pennsylvania Avenue

 

[MeteorWayne]

Sigh...another perfectly good physics topic ruined by a link to the SDC front page

 

[origin]

Infinity is the center of the Universe. So Infinity being (A) It is as big as A to the first power. A x 1=1A. So to answer your question the Universe is 1A in size. Since one can be of any size. 1A remands the same.

Huh?

 

[harper05]

2 questions

1) if the universe is 46 billion ly wide. and 13.7 b ly old. wouldnt that mean that objects with mass(galaxies, stars, ect.) on the opposite edges of the universe are moving away from each other at a rate of roughly 3.3c. Is that possible if you agree with einstien and relativity? IE nothing is faster than light. or light is constant.

2) also if the galaxy that we see in our telescopes that is 15 billion ly away is moving away at 3.3c or at any rate greater than c we would have never been able to see it in the first place. so how do we assume that this galaxy is 46 billion ly away?

BTW.. My pit bull Meatball knows where the center of our universe is... He just wont tell me...

 

[maxihipo]

The center of the universe is wherever my wife is standing (sorry gang, it had to be said. I promise more useful contributions in the future).

 

[Hogan_314]

I'm not much on theories. But if Hubble can see 13.7by in one direction, why not have it look in several other directions and see what's up.

Try a sphere or ball. The top is North, the bottom south. At the so called equatorial plane, mark out spots of O degrees 90, 180, and 270. If Hubbles first deep field view is considered North for just the sake of argument or reference point then point Hubble ( or Spitzer or JWST ) at these other 5 arbitrary points and take a picture. See what the differences are.
Adjustments can be made to avoid looking through the milky way and the sun and so on.

I think it took 10 days to take the first deep field picture in 1995. With an upgraded Hubble is now in service what can it see better then ever before?

http://www.cosmiclight.com/imagegalleries/deepfield.htm

Most scientists thought the proposal and implementation of Hubble's first deep field survey was a waist of valuable time and resources. Yet it turned up valuable insights.

Will the same conditions and age be found at the remaining 5 arbitrary points? Will the edge of the cosmos be 13.7 by distance in every direction? That would make Earth the center of the universe. Some how I don't think so, but that's speculation for you. I think Hubble can afford a few more 10 day exposures of the outer reaches of the cosmos. You don't know unless you try.

 

[SpeedFreek]

2 questions

Hi harper05! Those are two very good questions.

May I suggest you have a look at the following PDF file, it is a very good explanation of how the expansion of the universe works.

Misconceptions about the Big Bang

I will be happy to explain any questions you have, but I recommend you read that first!

(You are at the centre of Meatball's universe!)

 

[SpeedFreek]

I'm not much on theories. But if Hubble can see 13.7by in one direction, why not have it look in several other directions and see what's up.

Will the same conditions and age be found at the remaining 5 arbitrary points? Will the edge of the cosmos be 13.7 by distance in every direction? That would make Earth the center of the universe. Some how I don't think so, but that's speculation for you. I think Hubble can afford a few more 10 day exposures of the outer reaches of the cosmos. You don't know unless you try.

We have done so. Hubble has done a deep field view in different directions and sees that pretty much the same thing is up. We have distance measurements across the sky that show us that the edge of our observable universe is 13.7 billion light-years in all directions. We are at the centre of our observable universe, as our universe seems to have had a beginning, so light has only had a certain amount of time to travel. Thus, we see the same distance in all directions.

 

[Dblspace]

There are already 34 replies, & I haven't read them all, but has anyone considered this: *If* the universe is rotating, & if one could detect such rotation from within, then finding the center is merely a matter of finding the midpoint between the two "poles". Just a thought.

 

[Jerromy]

IMHO the center of the universe and the center of matter we see are two different questions. The infinite space around our universe can have no center. Our universe can indeed have a center of "gravity" which implies that all mass contained in a supposed 46 billion light year radius can collectively pull equally on one point of space. That is very much different from the assumption that all mass started in one definite point and all mass expanded equally outward preserving that initial "center of gravity".
As far as the "multiverse" issue of center it could be possible that many "universes" of equal mass could exist at equal distances from "our" universe and their gravity would cancel out. On that train of thought the CMBR could be radiation that has travelled trillions of years throughout space from other big bangs of other universes and the discrepancies could be where our tiny little bubble of gravity or other universes had bent their path. It is to my understanding that the CMBR is mostly typical in all directions with the exception of minor variances in few directions. It has been argued that those minor variances made the difference between a universe of variance gathering into stars, galaxies, etc. versus a universe where all matter expanded outward evenly into what would be no more than a balloon of dust around an empty void.

 

[nhorchidguy]

Just joining into the fray here, but I think that in search of this theoretical centre to the universe, you are making some very loose assumptions. First thing I think everyone is assuming is that the universe has expanded evenly since the event of the Big Bang, however the images of the CBR shows that this is not the case (granted, when the Bell Labs experiment happened they reported that the noise seemed to be coming from all points in the sky), however the material in the universe appears to be knotted. Also, in order to locate this theoretical centre, what are you going to base this upon? Since we know that visible light did not come into being until the gasses collapsed under their own gravity and the first hydrogen atoms started to fuse, we are already talking about a long period of time passing by allowing the matter in the universe to create uneven knots. Your other possibility is to try and find the gravitational centre of the universe (attempting to find a central point that ALL matter in the universe appears to be rotating around). This is likely your best bet for finding the theoretical centre of everything, however, you are talking about very long time periods to be measuring, and likely could never be found during the lifespan of the human species. For what its worth.

 

[nhorchidguy]

And to add one more thing...even if there is a centre of gravity, not all matter may be pulling on it evenly (which would imply that everything expanded evenly)...There may be more matter on one side, causing the centre to wobble, just as a star is made to wobble by its surrounding planets.

I'll shut up before I get punched in the mouth )

 

[malcor5]

ask rocket scientists & theoretical physicists a simple question and you get multi-dimensional manifold answers! here's the simple answer... i am the center of the universe.

 

[RandyExplorer]

Awesome discussion and thoughts from you all!

Assuming the Big Bang originated from a singularity (a single point), then a finite spot exists from which the known universe inflated. I'm perplexed that no one has a rough estimate of where this point is located relative to Earth now. Why can't we look at other galaxies and calculate vectors (direction of motion plus magnitude of velocity/acceleration) for each one using doppler shifts. If we follow the direction of this vectors back in time, shouldn't we converge at the center of the universe?

Here's a complication (one of many) that comes to mind as to why this may be difficult. Given the age of the universe and the fact that galaxies are closer together the further back in time we go (as the universe shrinks), collisions between galaxies are highly likely (perhaps unavoidable). Collisions can change the vector (direction and speed) of galaxies. So we can't just triangulate by picking 3-arbitrary galaxies and following their vectors back in time until they converge to the center of the universe. Perhaps we need to look at thousands of vectors from thousands of galaxies. Then look for the most common vectors and perhaps ignore the oddball trajectories that could be ignored due to prior collisions. If we do this, will a trend emerge that tells us where the center of the universe once was when it was a singularity?

As an aside, does anyone know of a book that discusses this topic (locating the center of the universe, if possible)?

 

[SpeedFreek]

May I suggest that everyone reads the PDF I linked earlier:

Misconceptions about the Big Bang

It explains a lot of the concepts being asked about in this thread.

 

[mabus]

Before the BB, there was no space, time, or matter as we know it. So with the properties of the universe I believe to be correct, logic indicates a finite universe with a center. I always point out that this is my belief and not fact, but all other ideas on this subject are beliefs and not facts as well.

We do not know that before the BB there was no space and time. All we know is that before the big bang, the universe was unimaginably small ( a singularity ). At a singularity our current understanding, and our ability to mathematically work through what occurs breaks down. It is impossible to say with any reliability what the conditions of the universe at the moment of the big bang, and it's state previous to this may have been, with our current knowledge. We would need a better set of tools (Grand Unified Theory) to be able to make such statements.

 

[globus_hystericus]

My first post, so be kind :lol: A few years ago I had the good fortune to take a graduate course in GR and review recent findings relevant to the discussion. To limit the discussion to theories verified so far, general relativity, and make a few reasonable assumptions: the universe looks the same in all directions and the composition is the same everywhere, then GR gives three choices to shape of the universe: open, closed and flat. To make a long story short recent measurements by COBI and other spacecraft have pretty much nailed down the shape of the universe as completely and amazingly right on the money FLAT. That means the universe is and always was infinite in size. Don't be confused by the big bang and universe the size of an atom point of view. The big bang was a singularity and thus can't be characterized but right after the very hot early universe was already infinite in size. Then it got even bigger! How can infinity get bigger? Simple, every point moves away from every other point in time. Also don't be confused by the size of the universe being 46 billion light years across, that's just the observable part, the part within our light cone stretched out by inflation. The rest of infinity is still there, remember assumption number one and two (isotropy and homogeny). As for the center, well, its everywhere, or nowhere; every point can consider itself the center of its observable universe but there is no true center as in what is the center of a geometric sphere.

 

[DatSpaceMan]

Uranus is most likely the center of the universe. Don't ask me how I know that...

 

[mabus]

There are already 34 replies, & I haven't read them all, but has anyone considered this: *If* the universe is rotating, & if one could detect such rotation from within, then finding the center is merely a matter of finding the midpoint between the two "poles". Just a thought.

This is so simple that it's just awesome

As far as I know no one has ever done this, and while we believe it has no center, I'd be extremely interested in the results. You never know, groundbreaking scientific revolutions have occured by doing what seems brainnumbingly obvious and finding the exact opposite of what you expected as a result. Assuming the observable universe as a sphere, we should be able to measure the movement of rotation of galaxies around the theoretical poles (even if the galaxy extends far beyond the observable universe). And we should be, in this way, capable of measuring the rotation, the curvature and probably even it's size. I'm really curious if anyone has ever tried such a thing or ever even thought of it before.

 

[bushwhacker]

after reading all 3 pages of this. i have seen one person whose teen age daughter is the center of the universe, another whose wife is the center, and another who thinks he is the center.. adding this to the fact that my grandson belives everything revolves around him only proves to me that michio kaku is correct in saying there are multiple universes

 

[SpeedFreek]

Before the BB, there was no space, time, or matter as we know it. So with the properties of the universe I believe to be correct, logic indicates a finite universe with a center. I always point out that this is my belief and not fact, but all other ideas on this subject are beliefs and not facts as well.

I would just like to point out that I did not say that, FlatEarth did. Somewhere the quotes have been swapped.

 

[FlatEarth]

Before the BB, there was no space, time, or matter as we know it. So with the properties of the universe I believe to be correct, logic indicates a finite universe with a center. I always point out that this is my belief and not fact, but all other ideas on this subject are beliefs and not facts as well.

We do not know that before the BB there was no space and time. All we know is that before the big bang, the universe was unimaginably small ( a singularity ). At a singularity our current understanding, and our ability to mathematically work through what occurs breaks down. It is impossible to say with any reliability what the conditions of the universe at the moment of the big bang, and it's state previous to this may have been, with our current knowledge. We would need a better set of tools (Grand Unified Theory) to be able to make such statements.

First off, I made that statement, not SpeedFreek.
Second, the Big Bang theory says everything came from a singularity: matter, energy, space, and time. Before the Big Bang our universe did not exist. Time did not exist either, so there is no "before the Big Bang" according to the theory.
You may want to check out this site for more info: http://www.big-bang-theory.com/

 

[FlatEarth]

Before the BB, there was no space, time, or matter as we know it. So with the properties of the universe I believe to be correct, logic indicates a finite universe with a center. I always point out that this is my belief and not fact, but all other ideas on this subject are beliefs and not facts as well.

I would just like to point out that I did not say that, FlatEarth did. Somewhere the quotes have been swapped.

You wish you had.

 

[harper05]

Thanks alot speedfreak, recession velocity, It kinda hurts my brain but it feels good at the same time. Anyways very cool paper enjoyed it alot..