During my live chat last weekend, I got some great questions. One of those was "Where is the center of the Universe?" This is a question I get a lot when I give public talks, and it’s a tough one to answer. I give it a go here.
I’ll be doing another live chat this weekend (probably Sunday at 3:00 Mountain time again); check the blog here because I’ll post when I figure it out. I may change streaming sites; UStream clearly doesn’t like my set up. The video is choppy again.
If you went to BadAstronomy.com and found yourself here, never fear: the BA Blog has moved to its new home at Discover Blogs. The original BA site (with the Moon Hoax debunking and all that) is still online, too.
Phil Plait, the creator of Bad Astronomy, is an astronomer, lecturer, and author. After ten years working on Hubble Space Telescope and six more working on astronomy education, he struck out on his own as a writer. He has written two books, dozens of magazine articles, and 12 bazillion blog articles. He is a skeptic, and fights misuses of science as well as praising the wonder of real science.
DISCOVERmagazine.com: Latest Articles on Space DISCOVER Blogs: The Loom
May 2nd, 2008 at 8:16 am
I’ve seen a balloon used before to help illustrate this. One can imagine the surface of the balloon as a two-dimensional space, and as it is inflated its surface area is increased; essentially new space is being created. To a two-dimensional creature living on the surface of this balloon, he would observe his universe expanding around him and everything moving away from him, and might come to the conclusion that he is at the center of his universe. However, an observer on a different part of the balloon would come to the same conclusion.
I had an intro to astronomy teacher basically boil it down to the center of the universe being anywhere in the universe. Thus those of us who think we’re in the center of the universe aren’t too far off from the truth.
May 2nd, 2008 at 8:16 am
I’m going to have to call shenanigans on this one, BA. The Center of the Universe is located in the Fremont district of Seattle, WA
http://www.fremontseattle.com/center_frameset.htm
EVERYONE knows that.
May 2nd, 2008 at 8:19 am
Astronomycast did a podcast about this very topic sometime recently.
May 2nd, 2008 at 8:22 am
Actually, *I* am the center of the Universe. Eat that, Plait!…
Seriously, though: how does this stuff relate with all that speculation about extra dimensions stemming from string theory? I never quite got to wrap my mind around that crazy, crazy stuff. Where would those dimensions be, if not in space or time?
And also: thinking of the universe as tetradimensional (space-x, space-y, space-z plus time) wouldn’t the fact that time has no central point imply that the universe as a whole has no central point, since the center has to be central in all dimensions?
(Am I making sense?)
May 2nd, 2008 at 8:33 am
I love the subtitles!
May 2nd, 2008 at 8:34 am
This is interesting. I guess I can understand the no centre, no edge dealio. But in that case how do we measure the expansion? How do we measure the “time” back 13.7 Billion years (or whatever the latest count is).
May 2nd, 2008 at 8:40 am
Phew, nice job. I just tried to explain that to one of my students last night, and did quite poorly. So I emailed her your video to make up for my bumbling. Thanks!
May 2nd, 2008 at 8:51 am
Where would those dimensions be
They’re all around us and in us. They’re just insanely small, and they loop back on themselves. So even if a particle in your body could enter one of the compactified dimensions (and they can’t…particles are too big to fit), they would “circle” around the curved space within and come back to where they started almost instantly.
This isn’t getting into the non-compact “extra” dimension that’s part of brane theories…which is more like the old “hyperspace that’s bigger than our normal space” idea, but…well, different. I won’t say anything about that since I don’t know much about it even in layman’s terms.
May 2nd, 2008 at 8:52 am
Dr. Livio described this concept to me as “a loaf of raisin bread” when I was much younger. Gives it a kind of 3 dimensional visual, of raisins expanding out from each other as the bread bakes.
May 2nd, 2008 at 8:57 am
The problem with the raisin bread analogy (besides making me hungry) is that the loaf of bread has an outside edge and a center. The balloon analogy is more “accurate” in that respect, but it’s harder to explain to people that the entire universe is in the membrane and that the inside and outside of the balloon don’t correspond to anything. (Well, sometimes I think of them as representing time: the more space inside the balloon, the more time has elapsed…but that falls apart if the universe reverses its expansion.)
May 2nd, 2008 at 9:06 am
@Kingthorin
How do we measure the “time” back 13.7 Billion years (or whatever the latest count is).
I’m sure BA can offer a more detailed explanation (probably more accurate too) but the way it works is sort of like this…
We are pretty confident about the spectrum of light that is given off by a galaxy. We know what it should look like, what the frequency distribution is, etc.
When we look at a galaxy far away, we see that light is shifted toward the red end of the spectrum. This is due to Doppler effects, and the calculation that determines how much it is shifted is fairly straightforward. This allows us to determine the speed of the galaxy.
Studies have shown that the farther away a galaxy is, the faster it is moving away from us. Years of evidence indicates that this is the case. Consequently, the amount of red shift gives a reasonable yardstick to measure how far away things are, and give or take a few percent, red-shift appears to be reasonably accurate.
There are other ways, but this is, I think, still the main way these huge distances are calculated.
May 2nd, 2008 at 9:09 am
Point taken. I always envisioned ‘us’ as being one of those raisins (or at least our galaxy), and that the bread was time/space is a whole. I could definitely see how someone could get caught up the “crust” as the edge of the universe, or some other silliness. Sort of having to double back and explain that there is no crust in terms of relativity is going to glaze some eyes really quickly, especially to younger folk.
Inevitably I always get asked the “so what was outside of that before the big bag” question too, with people assuming some big empty space. Then I always have to fall back on the time/space conundrum. Lose them 80% of the time, get a “yeah, right” 15%.
Maybe we need some kind of “klein bottle” balloon?
May 2nd, 2008 at 9:17 am
So assuming earth is the centre of the Universe we see time back 13.7 Billion years wherever we look in the cosmos?
Also given the explanation above if we’re all moving how can we tell how fast other things are going or how far away they are or is it more that we’re measuring how fast they’re moving relative to how fast we’re moving? (Assuming things further back in time are moving faster than we are…,but that doesn’t work either because if things are moving faster somewhere and slower somewhere else that would imply directionality)
Universe scale physics == Confusing
May 2nd, 2008 at 9:17 am
You almost need an infinitely big loaf of raisin bread to avoid the “center/crust” problem, which of course leads to its own difficulties. -_-
Not surprising that it’s hard to explain. I’ve been learning about cosmology for almost three decades now and still can’t really grasp most of it.
May 2nd, 2008 at 9:19 am
@Spiv
“so what was outside of that before the big bag”
Ok, I know that was a typo, but now I keep thinking about the Big Bag theory of the formation of the universe …
It started out as an empty bag, and is being inflated? Once it’s fully inflated we get the Big Pop?
Then there are all sorts of possibilites for what’s inside the Big Bag: rocks, cats, a pig, jelly babies, etc.
May 2nd, 2008 at 9:21 am
Oh yeah, I forgot - Eddie’s in the space time continuum.
May 2nd, 2008 at 9:27 am
Toronto. “Nuff said.
May 2nd, 2008 at 9:32 am
NBwaW: speak for yourself, infinite raisin bread sounds like a solution to me, not a problem. I love raisin bread
doc: typo indeed. I’m envisioning the “big bag theory” is a primitive pin’ata, with galaxies inside. If they were like smores it would totally explain background microwave radiation.
Kingthorin: all things are moving away from each other (overall, obviously we’re going to collide with Andromeda someday so we’re talking ‘on the whole.’ Whatever point you place yourself in the galaxy you’re going to see things farther away from you moving away faster than the things closer to you. We’re measuring things relative to “us,” since relative velocity is the only velocity. We experience the universe in one timescale, one place, and one space. All we can do is judge things reletive to our scale, place, and space.
In a car your steering wheel and you are (hopefully) travelling at the same velocity, which means that for all intent you have made velocity zero reletive to those things. The farther you back out you’ll find you’re travelling reletive to the street lights, the rotation of the earth, the orbit around the sun, the stellar around the galactic, etc, etc. You just sorta have to pick one and measure against it.
May 2nd, 2008 at 9:34 am
They’re all around us and in us. They’re just insanely small, and they loop back on themselves. So even if a particle in your body could enter one of the compactified dimensions (and they can’t…particles are too big to fit), they would “circle” around the curved space within and come back to where they started almost instantly.
Hm… they’re sorta like tiny weeny little wormholes, then?
The analogies that describe the expansion of the universe work for me, BTW, except that in all of them 2-dimensional creatures living in an expanding ball of something are always in an universe that is expanding into something, in that case into a 3rd dimension they know nothing about. The analogies are either imperfect that way, all of them, rubber ball, baloon or loaf of bred alike, or imply that the same is true with our universe, that we are expanding into some extra dimension(s) we cannot detect. Which is a possibility, I guess, albeit just as useless as far as scientific scrutiny is concerned as the concept of deity.
But the stuff around strings and some aspects of quantum mechanics, that’s what really puts my poor little brain in a centrifuge.
May 2nd, 2008 at 9:36 am
No, I am pretty sure that I am the center of my observable universe.
May 2nd, 2008 at 9:36 am
infinite raisin bread sounds like a solution to me
Not if I don’t want to become a Naked Bunny with a Big Rump.
May 2nd, 2008 at 9:40 am
The Center of the Universe?
Bo Derek.
.
May 2nd, 2008 at 9:45 am
they’re sorta like tiny weeny little wormholes, then?
Well…kinda. Wormholes have discrete locations where they open up. Compactified dimensions are just like regular dimensions in that they exist everywhere. They’re just so darned small that you can never wander into one of them like you can one of the regular three dimensions. I’m still confused myself over if there are countless little “copies” of the compactified dimensions (which would be more like wormholes then) or if there is just the 10 (or whatever it is these days) of them, tiny yet existing everywhere at once.
Oy, yesterday black holes, today string theory. I think I need a nap.
May 2nd, 2008 at 9:50 am
I have to disagree with Jorge. If the universe is infinite by definition, ‘I’ am the center of the universe.
How can you find the center if you don’t know where the end is?
May 2nd, 2008 at 10:00 am
Seems to me you are asking us to take on FAITH that the universe doesn’t have a center.
When I hear this topic explained, I hear …
“Well it’s kinda like this … but not really … and 3D space can “curve” but not into any other dimension … well some people say space itself expands, but those who know, know that that’s not really true … yada, yada, yada.”
Instead of presenting these things as FACT, could you please start out with, “noone really knows, but here are some ideas …”
These kinds of explanations are worse than no explanation IMO.
May 2nd, 2008 at 10:00 am
When faced with confusing analogies I always go with the most delicious, so the rasin bread wins out over big bags or balloons in this case. A big bag of loaf sounds good.
3pm mountain time is 11pm over here, by which time I’m usually in no fit state to work the internet machine. Can it be a little earlier for all your European friends? You can practice your British bad language.
May 2nd, 2008 at 10:12 am
Mark: the issue is that it’s fallout from a very wild idea that no one really believed, but thus far has proven itself over and over again. It all really stems from the idea that light has the same velocity whether you are approaching the source of distancing from it. The implications of such a wild idea are staggering; the concept of space itself must be redefined from “lenght x width x height” to something that includes all sorts of changing, relative issues. Unfortunately for people doing physics everywhere, it so far makes sense to everything we study. Time passes differently close to massive objects than it does at a distance (GPS relies on this principle), 3 miles is 3 feet if you’re going fast enough, etc, etc.
This poses a huge problem: we can describe these things in complicated equations, and those who have studied them for a while tend to have a handle on it, but when you try to explain them to the general public you’ll find all the language was built for the Newtonian world, not the relativistic universe.
The physics ultimately results in a “no center” universe. Explaining that in a 2 minute video essay would be impressive. Generally it’s a good chunk of a grad program.
That isn’t to say it’s impossible. Science is good at eliminating possibilities, and determining probable assumptions, but “proving something” is an endless venture that often leads to other discoveries.
May 2nd, 2008 at 10:13 am
At 2:29, what was that noise?
May 2nd, 2008 at 10:32 am
Hi Phil,
I see that everyone sorta reinterprets the info to suit their understandings of explanations of things difficult to perceive without a perspective we are all comfortable with or better a common point of view. Granted, to conceptualize things beyond the scope of our senses can often be ignorant and quite wrong. people are famous for errors of logic when reasoning with uncertainty. To know the center of the universe would gain us what exactly? A landmark? A Starting point? Would it answer this question…Where did the big bang, Bang?
Thanx Allthebest Winslow
May 2nd, 2008 at 10:37 am
Seems to me you are asking us to take on FAITH that the universe doesn’t have a center.
You’re confusing scientists with preachers again. Scientists aren’t interested in sermonizing to sheep; they expect you to do a little work and a little thinking for yourself. If you are taking things “on faith”, that’s your fault, not Phil’s. The research and analysis is out there and easy to find.
May 2nd, 2008 at 10:39 am
A few items that might help:
All of the analogies fall into the problem that people will inevitably fight the analogy. My response to my students is usually something along the line of “If I could model the problem exactly, I wouldn’t need an analogy”
“Extra” dimensions. Dr. Michio Kaku summed it up best for me in one book. To paraphrase: The reason we can’t envision extra dimensions is because our brains never evolved to deal with them. You’ve never been hunted by a four dimensional hyper-tiger, so there is no reason for your brain to worry about it.
Another way to think about the extra dimensions is as “degrees of freedom”. They just allow you to move a different way. One analogy I’ve seen is an ant walking along a strand of a rope. The ant just walks forward, but the actual motion is a corkscrew.
finally, the universe is not expanding into anything. Its just getting bigger.
your milage may vary.
May 2nd, 2008 at 11:02 am
Look, the balloon analogy is an ANALOGY. That means its is similar to the real thing, but is different than the real thing in some respects. In the balloon ANALOGY the curved surface of the balloon can CURVE because, in reality, there is a third dimension for the balloon to curve into. If we up the ANALOGY by one dimension — in order for a three dimensional space to CURVE, there must be at least a fourth dimension for it to curve into. No? But we are told that there is not a fourth dimension, or at least that a fourth dimension isn’t required. If we ask “How so?” We get, “trust me”.
Also, we are told we can go forever in a direction and never come to an edge even if we could travel faster than the speed of light and faster than the speed of expansion. The only conclusion that makes since is that the universe is infinite. But how can an infinite universe “expand”? It can’t. But we’re told, “trust me”.
We are also told that the universe expanded from an infinitly dense state. How long does it take to get from here to inifinity? You can’t do it. So how can we get from infinitely dense to where we are at (nowhere close to infinitely dense). You can’t. It doesn’t matter if you have 15 billion years or 15 trillion, trillion, trillion, trillion … years. You can never get from infinity to something less than infinity. “… just trust us”
These are a FEW of the things passed off as knowledge that are really nonsense.
May 2nd, 2008 at 11:03 am
If there’s a bright spot to the center of the universe, you’re on the planet that it is farthest from.
May 2nd, 2008 at 11:03 am
There are multiple centers to the universe.
Proof:
Look at my 3 teenage daughter.
May 2nd, 2008 at 11:16 am
Well, I thought I understood this. Then Phil Plait comes along and says “well actually in some interpretations you don’t necessarily come back to where you started from if you travel in a straight line, but there is still no edge to the universe AND there is still a finite amount of matter in it”.
Que?!
I give up now. I want comfort. Where’s that jar of peanut butter?
Just think, though… I would really like it if there WERE an edge. Imagine how cool it would be to live at the edge, and have half the sky black!
May 2nd, 2008 at 11:18 am
How’s this for comforting: The universe doesn’t need to make sense to you. In fact, it doesn’t even know you’re there…
May 2nd, 2008 at 11:18 am
huh?
…are you saying you don’t know or it doesn’t exist?
May 2nd, 2008 at 11:26 am
@Mark: Ah, the tedious old “I don’t understand it, therefore it can’t be true” argument. It never gets any more convincing.
If we ask “How so?” We get, “trust me”.
Unless you’re willing to put some work into understanding the math and physics involved, what else do you expect? There are these things called “schools” and “libraries”. Look into them.
But how can an infinite universe “expand”? It can’t.
Why not? Show your work.
We are also told that the universe expanded from an infinitly dense state.
Infinitely dense? Mmm, nope. Have you actually read a book on cosmology in the last 25 years?
These are a FEW of the things passed off as knowledge that are really nonsense.
Yes, specifically, the things I highlighted in italics in this post. Stop whining about “faith” and read a couple books. Learn! This isn’t a church, and you won’t be spoon-fed. If that’s too hard for you, then I suggest you go back to your insular little world and leave the real world to the people who can deal with it.
May 2nd, 2008 at 11:28 am
I am saying that just because some stuff doesn’t make sense to us does not make it weird our outlandish. It simply is the way the universe works. The concepts of general relativity are over a century old and have provided accurate predictions for numerous experiments.
Ducks can’t do calculus. I can’t comprehend relativity. I can understand it. I can make testable predictions with it, but I can’t wrap my brain around it at a fundamental level. Cosmology and String theory exist at the limits of human understanding, we might not be wired right to fully explore it…yet.
May 2nd, 2008 at 11:31 am
@ Spiv & EvolvingSquid
Thanks for the answers. I’m a little less confused now.
May 2nd, 2008 at 11:47 am
Mark:
1: we measure ‘distance’ in light-years for a number of reasons related to what you’re hinting at. Basically, it’s the only stable thing we can use because “distance” is really relative, and is intrinsically a component of time and visa versa. Traveling “faster” than the speed of light presents a problem in this. At best you travel close to the speed of light, and then you’re changing the experience of the space you’re traveling through. This dictates that there will be no edge by itself. Basically, if light becomes the yardstick (as is), and throwing the yardstick changes its length (which also happens to be the case), then you’ve got yourself a hell of a math problem to understand before you can figure out “how far” and “how fast” it, you, and the universe are coming to the other end of each other respectively. Ultimately the answer is a sort of “no.” Part of this is because if you were to find yourself “above the speed of light” relative to the earth, you cannot have had the earth as your origin. Another result of the whole relativity notion.
Extra dimensions I can best describe as an issue of the wrong system of geometry. Suppose for a moment you’re looking at the globe. We measure things by latitude and longitude as is, yes? It’s a reasonable method for dividing up the planet and describing your position on it. Other ways to do this: define a center, describe position by the differences in angles from one point on earth to that center. Option 3, describe the entire planet as the 3d space it lies in and describe your position in terms of x, y, and z coordinates that corrospond to places that intersect the surface.
These are all valid, but we’re all used to decribing the planet as a “flat” earth. I’m 750 miles from Virginia if I drive on the roads, but I’m really less than that if I had some sort of “direct” (subterranean) route.
The big bang is the other end of the yardstick problem. As density of energy/mass (which turn out to be another single) becomes higher, time is experienced differently. So much so that we can only figure to “within moments” of the “the moment,” and beyond that is an area of constant speculation and research. We have all the reason to believe right up back to that point, but then there’s a conflict between quantum and relativity that we haven’t yet resolved. Irrelevant, except to point out that “infinitely dense” is, again, the wrong language to describe, and additionally a situation that we don’t have, or claim to have an answer to. We can imply that the situation of energy/mass density must continue backward, but how is a mystery. “How long” is the same question as “how big,” because again, we’re asking light-years as the yardstick, and blatantly throwing “how humans experience years” in its place.
So again, we’re using the wrong language, because we’re trying to use our experience. The right language would be something along the lines of “the universe’s timespacebitty goes on forever, and the relative timespacebitty between parts is expanding, and that’s resulting in a reduced massenergydelio density reduction, which happens that we should experience less energy and more mass as timespacebitty goes ‘on-without-implying-a-time-only-component’.” Quickly followed by “No, I’m not on drugs.”
While the questions your asking are, in a way, the “wrong” questions, it doesn’t make them bad ones. In fact they’re fantastic questions because they help to emphasize how wierd it all really is. I wouldn’t expect anyone to accept it as fact without beating the dust out of it and thinking about strange problems that “lightspeed = only thing constant” presents.
May 2nd, 2008 at 11:54 am
No edge? Does that mean we’re trapped? Oh noes, I want outz!
May 2nd, 2008 at 12:02 pm
From now on, when my students ask about the center of the universe, I’m going to play this video.
fos
May 2nd, 2008 at 12:07 pm
VE
May 2nd, 2008 at 12:21 pm
In the beginning, God said “let there be light, and there was light”
May 2nd, 2008 at 12:22 pm
so are you saying now that you agree that Mecca is the centre of the universe?
May 2nd, 2008 at 12:33 pm
Hmm, is there a more “mathematical” explanation of what’s going on?
May 2nd, 2008 at 12:35 pm
leave it to a warping in spacetime to mess with my noggin
May 2nd, 2008 at 12:51 pm
kx: UCLA has this excellent primer to relativity:
http://www.astro.ucla.edu/~wright/relatvty.htm
It’s chock full of math and graphs to help illustrate; can’t say I have one describing how it all relates to cosmology though. There must be some good books out there, but I keep hearing math in books keeps them from selling.
I think if you can get a handle on relativity you’ll find this sort of cosmology is ‘implied.’ Backing it up with observation is the hard part.
May 2nd, 2008 at 1:01 pm
Spiv: Thanks, I’ll have a look at it.
I know some stuff about (pure) math, but I have no clue about “real” physics (i.e., the stuff where you start to actually use “real” math
).
May 2nd, 2008 at 1:22 pm
The acentricity of the GR universe isn’t exactly enough to keep me awake at night. It is, however, enough to get me up in the morning.
What I consider interesting is the prospect that all spatial dimensions are compact; but some are more so than others. So time and the three familiar large dimensions are just bigger versions of the hypothesized ones which we currently refer to as compactified. This might be accurate even if the physically correct solution to the GR field equations turns out to be an open universe. It’d be rather like the spectrum of conic section curves of varying eccentricities, starting from an ideal circle and progressing continuously through ellipses, parabolas and hyperbolas.
May 2nd, 2008 at 1:33 pm
Of all BA videos, this had the most bad (I’m not in the mood to say worst
) audio quiality. But great video; my head still keeps hurting, as it has been for the past many years.
May 2nd, 2008 at 2:21 pm
Bare Rabbit (any relation to Br’er Rabbit?),
IF the universe is infinitely large, and the universe is all there is, then it can’t get any larger (it’s a definition thing). If you say that something inifinitely large can expand, then I humbly suggest that it is you that needs to show their work.
“Infinitely dense? Mmm, nope. Have you actually read a book on cosmology in the last 25 years?”
Yes I have, and maybe the authors of these websites have too (just to give a couple of examples).
http://www.big-bang-theory.com/
http://archive.ncsa.uiuc.edu/Cyberia/Cosmos/InTheBeginning.html
I’m not affraid of learning, but you have taught me nothing. Quit demonstrating your great faith in theories that you don’t understand and try enlightening us all.
May 2nd, 2008 at 2:54 pm
I have not posted here in more than two years (and only once at that), I am merely an observer known by nobody on this forum. So if I am out of line and get kicked off of the forum, no problem here. But I have been reading several forums for two weeks, and there is one person who repeatedly scratches my chalkboard. I need to say something to all concerned.
Spiv, NBwaW, if I may – stop wasting your time with Mark. I have been reading his posts for the past 2 weeks and I am sick of seeing people trying to reason with him – one member got so frustrated with him that he ended getting kicked off the forum. Mark is not interested in reason or science, whatever he says about his “interest in science” in whatever forum he “discusses”. He is not interested in discussion. He seeks one thing and one thing only – to slam down anyone who has the audacity to consider, much less respect, any rules which are not dictated strictly by his “faith”, however intolerant that “faith” may be [and from what I have seen, it is most intolerant, far from my definition of true faith, hence the “” around his version of faith]. By trying to reason with Mark, you are merely setting yourself up for another pock shot based on anything but reason or scientific method. This is exactly what he wants, to divert you into a discussion about religion – namely HIS version of religion. You are wasting your time.
Mark – if you have such a problem with people who think in scientific terms, get off the site. I will argue no further. I am just sick of seeing your [explicative removed by author].
So if I get kicked off, it was worth the one-time post.
Have a great weekend all. This forum and [for the most part] the people in it are doing good things for SCIENCE – much to the dismay of Mark.
May 2nd, 2008 at 3:01 pm
There is the cosmic dipole. The Milky Way has motion relative to the cosmic microwave background radiation (CMBR). It is extremely tempting to use that as a direction to the center of the Universe. Of course, other galaxies would have pointers to somewhere else, as they have motion relative to us.
If the light from the CMBR started moving toward us 13.7 billion years ago, and the Universe started as an ultradense point, then why did it take so long to get here? The easy answer is that, though really dense, it had to be at least as large as the visible Universe is now. That makes the minimum size of the Universe really, really big. So big, even ordinary astronomical distance scales fail to work. The next term is Cosmological distances, and even there, it’s really too small a scale. A couple hundred years ago, people thought that stars really couldn’t be light years away - as that’s unimaginably far.
So, it’s probably OK to think of the stars as sitting on a fixed celestial sphere, and get in your car to go to work. Unless, you’re an astronomer, or care enough to get it right, or at least less wrong.
So far, we’ve not gotten the really hard questions right the first time, uhm, ever. So we may have gotten something fundamental wrong. After all, QM and GR are incompatible, right? There’s room for at least one more Nobel Prize - though I’m hoping for an Ig.
May 2nd, 2008 at 3:03 pm
Bunk! The center of the universe is a rock in Cleveland Ohio, on Case Western Reserve University campus. It’s just south of Euclid Ave and about 50 yards from where Michelson and Morley did their famous Ether Drift experiment.
And that is where all of modern cosmology went wrong. Michelson and Morley got a null result and thought they had proven that Ether doesn’t exist. How could they have known that, by a fantastic coincedence, they were only 50 yards from the exact center of the universe and so they weren’t moving through the ether at all.
Interestly, Cleveland is also the exact cultural center of the universe. It’s not that there is any culture in Cleveland. Cleveland is just surrounded by equi-distant and diametrically opposite pieces of culture, so it averages out.
May 2nd, 2008 at 3:10 pm
Saying that something is mind-boggling does nothing to address the
issue now does it? Even if the universe expanded a gazillionfold in a
fraction of a nanosecond it still stands to reason to say that it has
a width, does it not? OK, maybe not (?).
On a related note, what is the WMAP measuring if not the expanding
outer light boundary from the initial expansion? Am I to understand
that any point in the universe has such a light boundary? And in such
a case, is the universe infinite? I don’t mind to be boggled but
I would like to boggled for enlightenment; unfortunately
I do not feel enlightened by your post…
May 2nd, 2008 at 4:26 pm
NBwithAW good response to Mark!
Galileo said the book of nature is written in mathematics.
Believe it or not most any of us can follow the underlying math of Einstein’s Special Relativity, 1905. Do check your library. Its General Relativity, @ 1915, where things like Differential Geometry become needed to interpret the possibilities of Minkowski Space, etc. And therefore a lot of analogies are used for those of us not fluent in DG.
And Mark, the word from scientists is: let’s find more evidence; not: “trust me.” The latter is more at home in the likes of politics, religion, and sales.
And rather than dismissing ongoing science as “nonsense”, I admire those that have brought us this far in one century. And I encourage those involved to keep exploring, its one of our more noble traits.
Physicist/author Lisa Randall mentions that the soon opening LHC could start providing experimental results regarding the existence of extra dimensions.
And cosmologists of all denominations (Big Bang, Big Bump, or Big Dump, etc.) are eagerly awaiting more data from Hubbles’ successor and studies of dark energy, etc.
So rather than complaining that we don’t have complete answers, we should support those working on the process.
May 2nd, 2008 at 4:43 pm
This video was terrific! Wow! I am going to have to show it my students, too.
Question for anyone:
I’m convinced there is no center to the universe. But what about an absolute state of rest? As near as I understand, according to GR, there is no such privileged frame of reference. But couldn’t the CMBR be used to designate such a frame? Find the frame of reference where the average velocity of the CMBR is zero.
May 2nd, 2008 at 6:17 pm
CWRU Guy,
You’re close, but not quite dead-nuts-on. The center of the Universe is on the CWRU campus, but it’s not precisely at the rock. It’s really approximately where they planted the 7th generation Isaac Newton apple tree, which happens to be just a few feet off to one side.
The reason for this is simple: the universe slowly drifts in one direction, just as the ice sheet over the South Pole does. Periodically the pole marker at the Amundsen-Scott station needs to be updated, leaving a trail of out-of-date markers. In the same way the campus is accumulating a trail of universe-center-markers. The first one is the rock, the second the tree. What do you suppose would be an appropriate object to mark it again in a few years?
May 2nd, 2008 at 6:44 pm
I dont get it, wtf. Awesome vid though :). Boggles my mind. Science is awesome.
May 2nd, 2008 at 7:55 pm
Spiv - You can make smores in a microwave? Cool!
Dave C, the Milky Way is moving with respect to the CMBR, towards the Virgo Cluster, I think, so if you were moving in the other direction at some small velocity (relative to the speed of light) the CMBR would look the same in all directions. However, at some point a billion light years away, at some small velocity relative to local galaxies in that location, the CMBR would also look the same in all directions, but that point would be moving away from us a large velocity of the Hubble Constant times the distance (at H*10^9 ly km/sec).
May 2nd, 2008 at 7:58 pm
No edge?
Does that mean no restaurant??
@BA,
Good stuff. That helped me conceptualize a lot, actually. It leads me, too, to ask about a state-of-rest reference.
May 2nd, 2008 at 8:29 pm
Ah, that makes sense. Thanks, Buzz!
May 2nd, 2008 at 8:35 pm
Ow Ow Ow.. That made my brain hurts worse then an ice cream headache.
May 2nd, 2008 at 9:58 pm
Grrrr! Dialup at home and youTube blocked at work! I haven’t seen any of Phil’s vids. :’-(
May 2nd, 2008 at 10:32 pm
I know where the Centre of the Universe is and it ain’t lost.
My answer is a YouTube Video.
http://www.youtube.com/watch?v=23_O3asUZAU
May 2nd, 2008 at 11:06 pm
I have to giggle at those that think cosmology is made up down the pub and we just like it all to sound as weird as possible.
It’s a shame that people don’t understand what science is before they start to criticize ideas.
Science is a tool, a tool to answer questions. It is spoken in the language of mathematics and makes predictions. If the predictions are not borne out, the tool is discarded.
Cosmology, based on GR, works. It does so amazingly well (I use it every day) - It is based on a simple set of assumptions and makes testable predictions. It’s funny that all those alternate theories out there (which claim to be “logical” tend to be a pigsty of logic and mistaken ideas, which seriously lack any predictive powers.
Oh - By the way, space does not expand.
May 2nd, 2008 at 11:21 pm
The only people who know the location of the center of the universe are the Nibblonians from Futurama. They built their home 100 feet to the left because the view was better, IIRC.
May 2nd, 2008 at 11:21 pm
Jeffersonian,
No edge but the restaurant is OK. It’s at the end of the universe.
May 2nd, 2008 at 11:25 pm
And having thought about it a bit more, all restaurants that are around then will be the restaurant at the end of the universe. Of course, it may be that only one survives that long making it the restaurant.
May 3rd, 2008 at 1:34 am
[…] Bad Astronomy Blog » Where is the center of the Universe? (tags: astronomy space science) […]
May 3rd, 2008 at 3:15 am
Hullo from Spain! I’m just dropping a line to say thanks for the info… We’ve been learning very cool stuff lately with your vids, keep up the good work!
May 3rd, 2008 at 10:15 am
An interesting comment about this post on reddit - http://reddit.com/info/6i18j/comments/
May 3rd, 2008 at 10:24 am
Phil: If that keeps you up a night; good, because that keeps a lot of people up at night.
So I can blame my insomnia on trying to figure out where the center of the universe is?
May 3rd, 2008 at 10:52 am
whb03_debunk: Yeah, I kinda figured what he was really trying to get at was how it was supposedly just made up and therefor we should instead believe made up jesus books, because that’s somehow better (the old God -> Bible -> God ‘logic’). That’s cool and all, but for some dumb reason I still have the desire to give him a hint of education. Maybe if he starts to get pieces of it he’ll start to put it together.
Dave C: No matter where you are, or which way you face, the velocity of the CBMR is about 3 x 10^8 m/s.
Buzz Parsec: not only that, but you can measure the speed of light while making smores in the microwave: http://youtube.com/watch?v=9O2Keu6o3i0
May 3rd, 2008 at 1:59 pm
I agree that it is a natural question, especially because lots of science news for mainstream publication mention the edge of the “visible universe” (~13.7B lightyears out), as if we’re conveniently located in the center.
May 3rd, 2008 at 7:14 pm
You can has frame-rate?
May 4th, 2008 at 3:35 pm
@Mark
If we ask “How so?” We get, “trust me”.
You should probably see your doctor. You’re hearing things that no-one said.
I’m not affraid of learning,
Sorry, but I simply don’t believe you.
but you have taught me nothing
That’s because you’re afraid of learning.
Quit (…) and try enlightening us all.
You’re putting an enormous responsibility on NBwaW here… Why shouldn’t you try to do this yourself instead? At least to try enlightening yourself?
And who gave you the right to order NBwaW around?
May 5th, 2008 at 8:05 am
# Mark: IF the universe is infinitely large, and the universe is all there is, then it can’t get any larger (it’s a definition thing). If you say that something inifinitely large can expand, then I humbly suggest that it is you that needs to show their work.
Infinity doesn’t behave like you think it does.
Consider a hotel with an infinite number of rooms. It’s booked; there are no rooms open (there are an infinite number of guests). On one fateful day, an infinite number of travelers show up and demand rooms. What is the hotel to do?
The answer is deceptively simple: Move everyone currently in the hotel into the room with a number exactly double the number of the room they’re in now(*). Thus, the guest in room #1 moves into room #2; the guest in room #2 moves into room #4; and so on. The new arrivals are assigned the odd-numbered rooms.
Are there still an infinite number of original guests in the hotel? Yes. They’re in all the even-numbered rooms (there are an infinity of them), and no one does not have a room (show me who doesn’t). Are there rooms for an infinite number of new arrivals? Yes; there are an infinte number of odd numbers.
Put differently, (infinity) + (infinity) = (infinity).
(*) If you’re willing to allow me an infinitely large hotel with an infinite number of guests for this exercise, you can also assume that the guests won’t be inconvenienced by the move and that no matter where they move from or to, the room number will fit on the door.
May 5th, 2008 at 1:55 pm
Mark: We are also told that the universe expanded from an infinitly dense state. How long does it take to get from here to inifinity? You can’t do it.
Sorry. How dense is the singularity of a black hole again?
Let’s try it mathematically. If you have one kilogram of mass (m) packed into a volume V, what does the density (m/V) approach as V approaches zero from the positive end?
Does it follow from this that one kilogram spread evenly (or as evenly as possible) through eighty-four cubic parsecs is also infinitely dense?
Singularities have zero volume. Density is not an inherent property of matter. Just because the density is infinite, it does not follow that the mass must also be infinite.
Mark: These are a FEW of the things passed off as knowledge that are really nonsense.
They’re strongly counterintuitive, but if you bother to apply some actual math to the problem (and not your preconceived notions of infinity), they are clearly not nonsense.
May 7th, 2008 at 6:07 am
I’m still unclear how the universe can have open geometry (i.e. you go off in a straight line and never return) AND have no boundary AND have a finite amount of mass in it. A finite amount of mass cannot occupy an infinite space, no matter how much weird relativistic argument you employ. It’s a simple problem of counting particles
I am desperate to understand where I’m going wrong on this. I must have made a false assumption. Perhaps it’s the one about the finite mass. What’s the current thinking about the amount of matter in the universe? I thought it was out of the question that it could be infinite.
I’d be very grateful for some help with this question. If not, I’ll go and have another look online to see whether I can find out the answer, though I have tried before to no avail.
And don’t get me started about angular momentum, or we’ll be here all week… :S