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Why does the Universe look the same in all directions we look, considering an expanding Universe created by the Big Bang?
I've struggled to comprehend this. Looking away from the Earth, we are looking back into the history of the Universe's expansion since the Big Bang. Astronomers report that in any direction we look, at the farthest "distance and time" we can currently see, it appears there is a consistancy in what we see. Galaxies appear to be in the same "time state" of development, etc. If I carry this reasoning out to it's conclusion to where I can eventually see the edge of the Universe in all directions I look (assuming a finite Universe with a boundary), wouldn't that imply the Earth was actually at the center of the Universe? If the light coming back to me showing me the past is representing that in every direction I look I will see the same (time-wise) early state of the objects in the Universe, wouldn't I have to be in the center of it? If I wasn't centered, I should be seeing different "time states" of objects in the Universe depending on the direction I looked after the Big Bang expansion started.
I'm NOT asking this in a religious context. I'm NOT implying the Earth is actually in the center of our Universe to try to support any belief or faith. I'm looking for a theoretical physics explanation that will allow me to comprehend the observation without the Earth being centered in the Universe.
I just can't grasp the concept that if the Earth was a result of the Big Bang expansion, why does it LOOK like I'm in the center instead of off to the side closer to one edge of the Universe than the other? The probability of the Earth actually ending up in the center would be astronomical.
Rick Ryan 10+
5. Now, even though the farthest galaxy I can "see" now appears to be only 400 million years old, if I was actually standing on THAT galaxy looking out in all directions "right now", I would actually be looking out from a galaxy that WAS 14 billion years old since the Big Bang. The Universe around me from THAT perspective would appear to be 14 billion years old in all directions I looked. So I would "see" the same "sights" in whatever direction I looked from there too. Using the same "equipment to look", the farthest galaxy away I woud see is 400 million years old, and "behind that" (sic) would be the same Comsmic Background Radiation barrier because the Universe had expanded (inflated) the same way it did from my first perspective "here".
6. The above is the crux of what you were all saying about "the Observable Universe". Regardless of where my initial frame of reference starts out at, and due to a continually expanding (inflating) Universe, my Observable Universe would essentially give the same results for any observer wherever they were observing from since the Big Bang.
Totally layman's explanations above. The advanced math at the higher levels is a limitation for me, but I do understand some of it. The above explanations are the best I can do from my Common Core of Experience level about it all, though.
Thoughts, critiques, or totally frustrated "He's Confused Yet!" replies welcome.
(I'm Done. Fire Away With Replies)
Rick Ryan 10+
1. The farthest back into the history of the Universe I could hope to "see" woukl be limited by the age of the Universe itself and the speed of "light" (or more precisely, "light energy").
2. Based on the estimated age of the Universe since the Big Bang and the speed of "light energy", the FARTHEST "light energy" that is "visible" is the Cosmic Background Radiation barrier, but that is not part of my "visual spectrum" because it is Microwave Radiation. We can detect it will instruments, but the graphical representation of it is a "visible light spectrum" picture we produce ourselves (the "Map" picture).
3. Any "matter" objects I could actually see with my eyes in the visible light spectrum would be younger than the Cosmic Background Radiation barrier. As of today according to an Internet site, we just compiled a picture that shows galaxies that appear to be in the state they were at around 400 million years old after the Big Bang. Red Shift plays a role in seeing anything in the visible light spectrum younger than that as of today.
4. Because of an inflationary Universe, the Universe would be much "larger" that I could perceive it today. I can only "see" as far back as the amount of time it took for the light energy to get to me now. So (roughly) I don't have to actually be in the center of anythinjg to see the same thing in any directon I look (age of the Universe-wise).
(Continued in next post)
Jon Miner
You are assuming the answer is yes, the data puts us in the center of the universe. But the answer is no. The data puts us in the center of _our observable universe_. An infinite Universe seems incomprehensible to the human mind. If an event described as 'the big bang' occurred, it occurred in an infinite space. And in that space the speed of light is a constant in constant environments. That is it has one speed in a vacuum and another through a solid. But it has these speeds everywhere within the infinite Universe. What has changed is the precision and accuracy of our astronomical instruments. They are more capable now that before. They can see light that has come from farther away. All the light from 13 billion light years in any direction is arriving here after a 13 billion year journey. But 13 billion light years _beyond_ those galaxies lay other galaxies which are at this moment receiving light after a 13 billion year journey.
There is no center in the infinite Universe. This is incomprehensible to the human mind.
We want our starting points. We want our centers and boundaries. Our needs are based in our evolutionary history and our current psychology.
If an asteroid or comet somehow became sentient, it would have different needs and perceptions. In the hundreds of years of its journey around the Sun, only the lights in the black of space change regularly. Only once every thousands or millions of years is an impact on its surface noticed. Its concept of time would be totally different than ours. Perhaps the thought "I am moving" would take months to form in its mind. Perhaps it would believe it was at the center and would think "Everything goes around me."
Random Chance 30+
There was an expansion, a Singularity or from a Singularity.
and there are several Big Bang theories and several Singularity theories.
Supposedly.
Anyway, infinity is only a mirror image of eternity, thus it appears closed, flat and open all at the same time.
Distances seem immense and measurements accurate, but it is all happening in a mirror (image) and thus also appears to be infinite.
This mirror is created by mass that is great enough to bend light, creating what is known as Gravitational Lensing.
This has been seen from the outside of distant galaxies and the lensing is very clear to see.
But, just as within a large galaxy, or within our universe itself, there is a tremendous amount of light, light traveling through space, but it cannot be seen because there is little for it to reflect off of.
But still, there is so much, and the mass of the universe is so great, that it bends this light, creates a mirror-lensing image or effect "within the universe" (just as within large distant galaxies, and as seen from "outside" those galaxies), and viola! we have a mirroring effect that reflects eternity, which looks like infinity and appears so large and vast but is much smaller than what we believe or think we know it to be.
You seem to be the center because you cannot go anywhere in a mirror or image and you see reflections. You cannot leave it or you will cease to exist. And there is no destiny to go to. It looks like it exists over something called 'time" yet in reality, there is no such thing.
There is just another image going on into infinity and thus the creation of what is now being believed to be the "Holographic Universe" in which each part contains the whole.
It's all a maze.........................................................................................................ZING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
chen xin
and Bang is not necessary of course just a cup of tea .a better life
Ultima Nada
Another way to put it is, we are moving just as fast away from other things in the universe as things are moving away from us. Hence, there is no center of the universe.
Henry Woeltjen 10+
Let's take a look.
1) There's no way of knowing since our eyes, even with great help, can only see so far.
2) Nature has told us so much about the universe...I think we look up too often.
3) I don't believe any validity exists to the "big bang".
Why do we believe the "big bang".
Well because we assume the only way we could have produced this sort of state...is through a massive release of energy like a "bang".
Let me point out that "bangs" or "explosions" do not create universal law when they occur.
When stars die, transform, or do whatever they do...it doesn't seem as it fit creates habitable planets in the process.
I gauge my perception on nature. As sensitive as nature is..and fragile...we came from a universe that adapts by exploding and creating "states" that life isn't even an option?
Maybe the model for the solar system was wrong.
Maybe the Earth sits still...and all other matter rotates around it?
Ken brown 30+
Robert Winner 50+
I think I was put here to confuse the issues. How am I doing. LOL Bob.
stan kinsman
If yes,that tells me why it looks the same.
As for the big bang-seeing as we know really nothing yet,it is just another idea waiting for the truth.
Mark Kurtz 20+
Perhaps the best and most honest conclusion is we see the cosmos from a narrow and extremely limited perspective. There likely are many universes within the Universe. What is man that we expect to see it all? What is man to even think a human someday will see it all while yet remaining human? What is man to expect to see stereoscopic perspectives of anything of this vast assemblage of planets, stars, masses of gas and particles?
Maybe its best to accept we, as individuals, will move on to other levels of life far above human and with such advances we will have opportunities to see more, perhaps a lot more and from an entirely different perspective! Imagine that! What realities await us for the next life?
stan kinsman
Energy cannot be destroyed,it can be altered.That explains life & death to me.We just see the sun rise from a new angle.
Simple thoughts from a simple mind.
Nothing is really that complicated,however those explanations can be a bit long winded .
Science keeps proving to me that the words of my grandma are true."All is connected".
Todd Levesque
Todd Levesque
natasha nikulina 50+
It requires a good deal of belief ; it can't be tested, can't be explained, but it is necessary for everything that have fallowed to be explained and tested .
Seems like a free scientific miracle to me :)
Rick Ryan 10+
I can't test the beginning, nor explain the beginning, but it is still necessary for me to do so if I want the truth about it. So I have no choice except to place a great deal of "belief" in it.
Seems fairly miraculous to me to be doing that, too.
Just because a Human Being can't presently comprehend something that happened doesn't mean a miracle occured. Ask any magician how that works.
natasha nikulina 50+
I don't believe in the Holly Other either. Did we move any further from the Cartesian mindset, 'Right vs Wrong' kind of thinking ?
I guess, we did, we have fuzzy logic, fractal geometry , Mandelbrot set , holographic image and QM . All these things do not provide with the answer but generate another attitude. Magic mystery, reverence are not alien to it and no way contradict science. There is no need to believe in anything, the answer is here, what is the right question ?
I wish i knew :)
John Smith 30+
It requires a good deal of belief ; it can't be tested, can't be explained,"
It can be falsified, that's enough, also, Rick Ryan wrote a pretty good reply on a philosophical level.
natasha nikulina 50+
Theodore A. Hoppe 200+
Rick Ryan 10+
Thank you for that link! In all my readings and examples illustrating the balloon analogy, I never saw the explanation (or comprehended it) in the sense that the 2D balloon surface actually represented the 3D of space. I had the "fallacy" as explained in the link that the "interior" of the balloon was actually part of the Universe too.
Feels great when someone helps in getting you to "think outside your own box" and understand concepts in a different way.
This is not to say that any of the other posts here have not helped me to better understand the concept...they all have. But Theodore's link above is the big one that made the light bulb illuminate in my brain. And as a retired "teacher" in some disciplines, I am aware that it can take different ways of presenting something to a student before that light bulb illuminates.
Thank you all !!!
walter crockett
Mark Hurych
By the way, don't worry. NOBODY understands this in a way that makes sense with our slower-than-light-speed way of seeing things as human beings. So when you wonder and puzzle over these questions, you are among good company (present and past).
=
Eric Wexler
natasha nikulina 50+
you are right, it's really difficult if possible at all to understand , but you know, this gut feeling ... it prompts me that there is a point :)
Thanks for sharing !
Mark Hurych
natasha nikulina 50+
Frankly, i don't know :)
patrick stack
and therefore, in a way, we are at the centre
since in every possible direction outward from the earth we have the same "distance" of.... infinity
On the other hand infinity may alsobe a relative measure
since an infinitely large body would necessarily find itself in a finite universe
no one really knows, or do they....
Theodore A. Hoppe 200+
Rick Ryan 10+
Quite the opposite. I was asking why it would APPEAR we were in the center, as that just seemed astronomically incredible. As an aside, I'm agnostic, so I'm not trying to "prove" anything one way or another.
Mark Hurych
As far as APPEARANCE is concerned, I think it's an important observation that the night sky is mostly dark. If space were infinite (in Euclidean geometric terms) we would see an infinite number of stars which would cover every possible piece of sky.
With every question and every answer, no matter how fleeting or partial, awe and wonder seem to be appropriate responses.
mark
Rick Ryan 10+
Am I missing something? Does it have to do with your condition of a Euclidean geometric observartion?
http://en.wikipedia.org/wiki/Olbers%27_paradox
Diana Pederson
As to why it looks like we are in the center, there is an interesting talk by a theoretical cosmologist that I found interesting which specifically talks about why we look like we are in the center (look for the slide where there are two grids of dots). His context in the talk was how we could measure that the universe is expanding. Note that the speaker has several books published, so if his talk is helpful, he may have other materials which may interest you.
http://www.youtube.com/watch?v=7ImvlS8PLIo
Consider also the analoggy of being lost in a large orchard. The rows of trees seem to go on for a very long way, even if you are closer to one edge or another. I will depend on how much of the orchard is visible to you.
John Smith 30+
John Moonstroller 20+
Bear in mind that the singularity is a three dimensional object. We can't tell where it was located because, of course, all things appear to be moving away from us. No matter where you are in the Universe. It would look the same to any observer.
The calculation used is v = Hod
(v) is the speed at which a galaxy moves away from us
(d) is its distance.
Ho is the constant of proportionality, now called the Hubble constant.
The common unit of velocity used to measure the speed of a galaxy is km/sec, while the most common unit of for measuring the distance to nearby galaxies is called the Megaparsec (Mpc) which is equal to 3.26 million light years or 30,800,000,000,000,000,000 km! Thus the units of the Hubble constant are (km/sec)/Mpc.
Farrukh Yakubov 50+
It is logical to assume that, in the future light from unseen parts of the universe will reach the Earth, thus become observable. However, light from distant parts of universe may never reach us because of the fact that space itself is expanding.
It cannot be proven that the Earth is at the center of Universe, but neither that the Earth is not at the center. However, if a random point were to be chosen from a inside a sphere, probability of it being anywhere else but the center would be almost 1/1.
All of the above was based on scientific thinking, but here is interesting analogy to observer of universe on Earth. If a hunter were to be lost in large forest that is heavily fogged, he would see trees all around at the same short distance. No matter how long he waits, he wouldn't be able to tell wether he was at the middle or the edge of the forest.
vikram singh
Matjaz Zibert
But the most important in this model is the fact that the real center (of Universe) is not on the balloon surface (our 3D space). It is inside of the balloon (the 3rd dimension looking from balloon surface).
Now, try to imagine a 4D sphere that expands. The surface of this sphere is our 3D Universe that is expanding too. And is expanding in the same way in all (3D) direction you look. You can't find the center, because it is in the middle of the 4D expanding sphere. Only if you look in the past at the time of Big bang, the radius of this sphere becomes zero and the center and the 3D surface meet in a single point.
Gord G 30+
It seems simple enough. We define the universe... so why should we be surprised we're at the centre of it? Okay I'm still kidding.
But if you find the answer, let me know, I have a couple of parking tickets that I would like to avoid paying. (now I'm just being abstruse). Good night. ;-)
John Moonstroller 20+
Around 1920, no one realized that what they called the Universe was actually the Milky Way galaxy. Imagine that! When Einstein was creating the General Theory of Relativity, his generation thought the Universe was no larger than a Galaxy.
I guess it was around the late 60's when the general population understood that the Milky Way Galaxy was just one of many Galaxies. Today, the average 7th grader knows more about the Universe than Einstein's entire Generation.
But, help is on the horizon. You may have your answer soon. If you can understand this information.
http://adsabs.harvard.edu/abs/2012ApJS..199....3R
If not you'll just have to speculate. There is no current map of the universe.
This is one very big question.
Good luck.
Austin R 20+
Rick Ryan 10+
I was familiar with the Red Shift concept before I posted the question, but not in the way some of the answers here provided. Same thing with the "quarters on a balloon" perspective...I had seen that before, but now have a different idea of what it was trying to explain.
Keep any other ideas coming. They have all been very enlightening to me for forming a better understanding of the Big Bang concept.
Frans Kellner 100+
Probably you've been dreaming some nights in a vivid way where you moved through some space and acted out all sorts of things. Where do you think that space is, in your head?
Another more intellectual approach is time. If light needs time to travel than all you see occupies another time, the star you see but not different also anything close. So from your point of perspective within space/time (singularity) you watch anything occupying another space/time. So you see history displayed before and around you. So it's not that all galaxies move from you but you move from everything else. And if I say you I don't refer to that body you occupy but to the center of your consciousness that projects that universe.
Random Chance 30+
Well here goes and I feel foolish.
I think it is all a mirror effect and that infinity is only a mirror image of eternity so it appears to go on and on.
Perhaps in that, distances and speeds and so forth, can be measured but they are fooling us all because it all comes from reflection.
If something has enough mass, it can and does bend light and space. This is called "gravitational lensing" and can show multiple images of one thing so that they look like hundreds of thousands of similar things, many different views of one thing, such as in cut crystal glass, that when you look through it, you see many separate images and can also make things look as though they are at different distances away.
The universe is big enough to do this and if there is enough light in the universe, and there is, then it could easily create a reflection of itself because all the light is bent, curved around itself, within itself and reflects itself or, what is there.
There, I wrote it out even though I feel like a child for saying it.
Barry Palmer 50+
Gail . 50+
I have had a physicist say that every point IS the center, because all that is is an expansion of a singularity meaning that we are living in an expanded singularity. This can be supported by considering the notion of "SpaceTime". There is only one time that every being has in common. That is the infinite moment of NOW. That abstract moment is our bond with everything else in existence.
PS: I'm not a theoretical physicist, but I do love pondering questions like these.
Rick Ryan 10+
Gail . 50+
Peter Law 30+
This is a great question. I am sure the boffins have answers, but nobody thinks to explain it to us interested amateurs.
Firstly I don't think we can be at the centre of a big bang. Everything would theoretically be moving away from the centre of an explosion, leaving, presumably, nothing at the centre.
When I first heard of red shift, I, like you, assumed that we were near the middle. However this was explained by picturing the surface of an expanding balloon idea. We all see everything with an equal red shift, no matter where we are. This is all very well, but surely if we looked outward, directly away from the centre, we would see nothing. No galaxies at all. This doesn't make sense.
Then we have something called "Quantised Red Shift'. This theory, backed by measurements, suggests that the galaxies are in concentric spheres at set distances from earth. This would infer once again that we are in the centre.
Finally, others tell us that the 'far away' galaxies look much the same as those 'closer' to us. They should of course look 'younger' the farther away they are.
What do I think ? Don't really know, but suspect that maybe our interpretation of 'Red Shift' could be off target.
:-)
Ps; I am a Christian, which may effect my perspective.