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Surprise Galaxies at the Edge of Observable Space
brindafella writes "A scientist at the Australian National University's Mount Stromlo & Siding Springs Observatories, Dr Paul Francis, has dicovered a string of galaxies 300 light years long, and further out than they 'should' be. The team were refused time on a US telescope because many American astronomers believed the observations were technically impossible. The findings have been presented at the American Astronomical Society meeting in Atlanta. 'We have detected 37 galaxies and one quasar in the string, but it probably contains many thousands of galaxies.' He said the galaxy string lay 10,800 million light-years away. See the animation here."
Much better luck loading with the story at NASA's site, including an MPEG version of the animation.
I watched C-beams glitter in the dark near the Tannhauser gate.
Yeah, it's actually 300 million light-years long. :) Kids these days and their new math.
I watched C-beams glitter in the dark near the Tannhauser gate.
And a link to a 63-byte file they claim is a "movie". Kids these days
You don't quite have the point. This surprise has nothing to do with distance from the "center" of the big bang, since there is no center.
What's important about these galaxies is their age. Since they are ten billion light years away, the light that is reaching us now is an image of their state ten billion years ago. When the universe was that young, galaxies wouldn't yet have had time to organize themselves into strings.
The most straightforward explanation is that the universe is older than we thought. That has already been postulated as a component of other theories-- various ideas about dark matter, the cosmological constant, etc.-- meaning it's not entirely contrary to current thinking.
So you're partially right, in saying this discovery will force changes in Big Bang theory. But that does not mean what you think it means.
should be the MOST CHAOTIC, not the most ORGANIZED, as they apparently are (being in string formation).
Actually, you're messing up what chaotic means in this case. A string formation may or may not be chaotic, depending on the creation mechanism. In the early days of the Universe, matter would be uniform, not "chaotic". If it was formed as a string, then this would be consistent with an early age, because it hadn't had time for their peculiar velocities to distort the formation. If they didn't form as a string, then it wouldn't be consistent with an early age, because gravity wouldn't've had time to pull them into that shape (assuming it could).
The light that's coming from the farthest away from us is uniform - we call it the Cosmic Microwave Background Radiation. And, amazingly enough, it's incredibly uniform and isotropic. Anisotropies in the CMBR are incredibly small.
If you doubt the Big Bang, get a microwave telescope and look around you. If a Big Bang didn't happen, SOME gigantic, uniform explosion happened, because there's this gigantic, uniform explosion everywhere around you. And it's redshifted by something like z = 10,000 : around 100,000 years after the Big Bang, if my memory serves. That is the universe, as it was very, very close to the Big Bang.
This observation just shows that galaxies formed quicker and faster than theorists predicted. This is not a big deal.
After all, theorists for a while had a hard time explaining how galaxies formed at all. The string formation may suggest that cosmic strings (1-dimensional topological defects) may actually have existed in the early universe. Cosmic strings have been "down on their luck" theoretically recently, as the preponderance of dark matter and energy have convinced many people you don't actually need cosmic strings. This may start them thinking otherwise.
"faith" to believe that that universe was created by chance than it does to believe that SOME outside, intelligent force "caused" it to be (the details of which are certainly open to debate).
Chance has a perspective issue. Saying something happened by "chance" and saying that it was "planned" is a matter of belief, not of fact. Nowhere do scientists say why something happened. Just how. Trying to use scientific arguments to justify a "why" is flat wrong - you're trying to justify a statement that requires evidence outside of a proper frame of reference. It's similar to the problems with the strong anthropic principle - fundamentally, from our point of view, it's indistiguishable from its opposite (oddly enough, because of the weak anthropic principle). You can't tell the difference between a "chance" creation or a "designed" creation by an intelligent force because they produce exactly the same results, because fundamentally, you have to produce a universe capable of having humans (the weak anthropic principle). We have no knowledge of the number of "dead" universes, nor whether or not "dead" universes could even exist. Therefore, from our point of view, there's no way to prove which is correct, and which is incorrect, and therefore, it's a matter of belief, not of science.
There was some editing of my entry by the /. team before it was accepted for public viewing. :-( Some other details were changed, too. My original posting quoted directly from the scientist's information. :-)
Looking at space, radio, science and computing from a 'down-under' amateur enthusiast perspective.
> This surprise has nothing to do with distance from the "center" of the big bang,
> since there is no center
I've heard this before, and although I don't disagree with it, I've never been able to wrap my brain around it. It seems to me that any explosion has a center, or a point of origin. Even one that expands out into "nothing" like the Big Bang did/is.
This is, unfortunately, a flaw in the name of the model. It conjures up the idea of an explosion of material into surrounding empty space, which is not what the Big Bang model describes. The expansion of the Universe is an expansion of space itself. The galaxies grow farther apart not because they are moving away from each other through space, but because space itself is expanding between them.
Not that that necessarily makes things easier for you. Fundamentally, this points out a failure of one of our most useful way of understanding thimgs: to relate them to things we already understand, or with which we are already familiar. For instance, when authors of cosmology books for laypersons construct analogies to the expansion of space and the resulting increasing separation of the galaxies, they use things like a loaf of raisin bread expanding in the oven. But that analogy is flawed: the raisin bread has space surrounding it into which it can expand (not to mention a "center"), while no such thing exists for the universe.
A better analogy in that it gets rid of the embedded center is to give up our 3D universe, and instead consider the 2D surface of an inflating balloon. Dots (galaxies) painted on the balloon's surface are all getting farther and farther apart from each other on the surface of the balloon (in space), but no place on the surface of the balloon (no location in the Universe) can be called the center of the expansion (the one place from which things started expanding apart). But this analogy is a bad one, as well. It makes an assumption about the topology of the universe (that it loops around on itself, or is "closed"); the Universe may be that way, but it need not be. More importantly, this analogy requires the existence of a 3rd dimension (the radial direction) separate from the 2D surface of the balloon; a change in the position of the surface of the balloon with time in that radial direction describes the expansion. But the Big Bang model doesn't require such a hidden dimension which is driving the expansion.
There just isn't something from our day-to-day lives which provides a decent analogy to the expansion of the Universe. It has to be understood on its own terms, without recourse to simple visualization. Not that this is uncommon in physics since the beginning of the 20th Century; for instance, quantum mechanics describes phenomena which are difficult to impossible to describe in terms of how things work in our common sense, everyday world. In the end, it comes down to a quote from (I think) Feynman (although he was talking about quantum mechanics at the time): "I don't know how to describe it in terms of something you're more familiar with, because I don't understand it in terms of something you're more familiar with."
> Yes, and no: depending on who you talk to, and the definition of Universe.
> The best one I can come up with is "all space which is connected (in a
> mathematical sense) and includes me at the present time". In that sense,
> regions of black holes are another Universe, for instance.
>
> There are other statements like "the Universe is everything that can be observed",
> which is a much more limiting definition (fundamentally, there's a ton of
> spacetime outside all of humanity's forward and backward light cones), or "the
> Universe is everything", which, well, pretty much occludes all "outside"-ness,
> because as soon as you find something outside, it's not outside. Oookay.
Is it meaningful to talk about the portions of the universe that are outside our light cones as being mathematically connected to us? You can say that they were, but not that they are. There's no such thing as an instantaneous "now" snapshot of the universe, just a snapshot of the current surface of the backwards light cone. In practice, "everything that I can observe" and "everything that is connected to me" refer to the same thing.
I shouldn't speak for the poster to whom you were replying, but I'm pretty sure that he was using the phrase "mathematically connected" in a topological sense, rather than referring to causal connection. If one meant connected in a causal sense, then you're absolutely correct that that means the backwards light cone by definition, and therefore means what I can observe. But you can also talk about the topology of space, and whether the Universe is simply connected, connected, etc. I think that's how it was meant; and that definition is different from what's observable.
From poking around on their website, here's a preprint article, and there's another paper which discusses spectroscopic confirmation.
These are Lyman emitting galaxies, initially identified using a special camera with narrow band filters targeted at this redshift (a previously known z = 2.38 cluster was in the field which I think is why they picked it). They then used a multi-object spectrograph (2dF) to spectroscopically confirm the redshifts (second paper).
Doug
Venn ist das nurnstuck git und Slotermeyer? Ya! Beigerhund das oder die Flipperwaldt gersput!
> and whose to say that the Universe doesn't oscillate?
That possibility is still definitely on the table, but it's losing support.
It has almost no support in the mainstream cosmological community, and hasn't for quite a while.
A universe that slows, stops, and falls back in a "Big Crunch" is a negative curvature universe. A universe that expands infinitely is a positive curvature universe. Between them you have a precise zero-point, a "flat" zero curvature universe where the expansion rate slows infinitely close to zero.
Actually, this is backwards. Traditionally, it's been positively curved universes that recollapse, while negatively curved universes converge towards a free expansion where the expansion scales linearly with time (that is, as the age of the Universe doubles, everything expands by a factor of two). So that's backwards. But also, in that traditional view, flat universes expand infinitely as well; they simply asymptotically approach (but never quite reach) an end to the expansion (I think you were trying to say that, but I wanted to make it clear).
But importantly, this view has neglected the possibility of a nonzero vacuum energy, or cosmological constant. That's why I used the adverb "traditionally" above -- traditionally, we've assumed there to be no vacuum energy, and set the cosmological constant to zero. We now have significant observational evidence that this was wrong. In the presence of a cosmological constant, it's no longer possible to simply say "negative curvature = expands forever, zero curvature = expands forever but asymptotically approaches stopping, positive curvature = recollapse." Those simple relations between curvature and fate no longer hold if there's a cosmological constant. It's true that the energy content of the Universe drives the time-evolution of its expansion; it's also true that the energy content of the Universe determines its curvature. But the presence of a cosmological constant changes the Friedmann equations in such a way that that simplistic correlation between curvature and how the expansion will proceed no longer holds true. This is illustrated by the apparent situation with our own Universe (see below).
There are very strong theoretical reasons to think that the universe has exactly zero curvature - precisely on the balancing point. On the other hand recent observations seem to suggest accelerating expansion, possibly runaway positive curvature taht would eventually rip apart everything - the Earth, atoms, even protons.
Actually, we have strong observational evidence that the Universe is flat (that is, has zero curvature), from observations of the primary anisotropies in the cosmic microwave background. At the same time, you're correct that recent observations indicate an acceleration to the expansion. But this is not contradictory when a vacuum energy exists. In fact, a vacuum energy is the only way to get an accelerating expansion; a negative curvature universe with no cosmological constant does expand infinitely, but that expansion does not accelerate.