Do We Live In a Giant Cosmic Bubble?

Khemisty writes "Earth may be trapped in an abnormal bubble of space-time that is particularly void of matter. Scientists say this condition could account for the apparent acceleration of the universe's expansion, for which dark energy currently is the leading explanation. Until now, there has been no good way to choose between dark energy or the void explanation, but a new study outlines a potential test of the bubble scenario. If we were in an unusually sparse area of the universe, then things could look farther away than they really are and there would be no need to rely on dark energy as an explanation for certain astronomical observations. 'If we lived in a very large under-density, then the space-time itself wouldn't be accelerating,' said researcher Timothy Clifton of Oxford University in England. 'It would just be that the observations, if interpreted in the usual way, would look like they were.'"

Comments

I know I do

[Anonymous Coward]

Like, cosmic, man.

Re:I know I do

[SleptThroughClass]

Apparently someone is indeed less dense.

Re:I know I do

[bugeaterr]

6000 years ago, god farted in a Cosmic Bathtub.

Re:I know I do

[SlowMovingTarget]

A brane-fart, eh?

I always wondered...

[clonan]

If this was why the galaxies appear to rotate to quickly at the edges.

Would the greater density at the galactic cores cause time to go slower and effect the apparent speed as observed from the exterier of the system?

Re:I always wondered...

[Goaway]

No. The gravitational forces required for time dilation to be that strong are many orders of magnitude stronger than what you'll find on the galactic scale.

Being special

[Harmonious Botch]

Ok, I'll believe that there are regions of space that are more dense than others. I'll even believe that we are in one of them. ( This is no harder than believing in dark matter and dark energy, and it's before breakfast )
But what I find hard to believe is that we are in the exact center of such a region. So therefore, the universe should appear to have different properties in different directions. Has anybody seen that?

Re:Being special

[BigGar']

Man you ain't kidding. Take a look at the Capitol Hill region of space. That is one ultra dense region of hot air, that isn't just warping space-time this is a region of space where the wildest of idea's are warped into reality.

Re:Being special

[someone1234]

Except if such specialties make our sentient life possible (or much more probable).

Re:Being special

[2names]

Density distribution throughout the universe (ours, at least) is relative to the scale at which your measurements are made. Follow me here...

If you get far enough away from this universe, and I'm talking 'Douglas Adams' far, this universe would appear to be perfectly uniform. However, the closer your observation point becomes, the easier it is to distinguish the clumps, bumps, peaks, valleys, troughs, etc. in the density. At a very close, human-type scale, the density changes are very easy to spot. How dense is the space between the Earth and the Moon as compared to the Earth itself?

Re:Being special

[LordNimon]

Why is it so hard to believe? Let's say for instance I tell you that there is a one-in-a-million chance that a person will have a particular dream. Every night, 300 million Americans go to sleep. Would you find it hard to believe that at least one person has this dream every night?

And what if you were that one person last night? Would you think you were special? You would, if you were bad at math.

So why is it hard to believe that our planet exists in conditions that have incredibly low odds? The universe is not only more vast than anyone can imagine, it's also been around for over 13 billion years! For all you know, these "special conditions" you complain about could have happened a million times by now.

Re:Being special

[meringuoid]

But what I find hard to believe is that we are in the exact center of such a region. So therefore, the universe should appear to have different properties in different directions. Has anybody seen that?

There's an unexplained anisotropy in the cosmic microwave background. Hot and cold spots don't appear to be quite randomly distributed. Nobody's come up with a good explanation, and it might be an instrumentation error or due to some local gravitational anomaly - say, lensing around the next supercluster over - but at the moment it's very unclear.

Re:Being special

[Chris Burke]

But what I find hard to believe is that we are in the exact center of such a region.

How exact do you think it has to be when we're talking about cosmic distances? Distances where being in the Milky Way vs Andromeda wouldn't make much difference in how the distant universe looked?

Re:Being special

[John Hasler]

We need not be at the exact center. Closer to the center than to the edge would probably suffice.

Nor does ours need to be the only bubble: there could be billions of them. Thus we need not be unique: just not quite average (but then, being perfectly average would itself be unlikely).

Re:Being special

[ShieldW0lf]

You're believing something the opposite of what the premise of the article is. The premise of the article is that we are in a bubble containing a void, not a highly dense space.

I think we really need to restructure our underlying philosophy of what existence is. I've been chewing on this concept for years:

This "universe" isn't infinite. It's a 4 dimensional object, with a large but quantifiable amount of mass/energy, and this mass/energy has permutations across x, y, z and t. You see a 3 dimensional object with dimensions x, y, z moving through t, but observed from outside the t dimension, it's a 4 dimensional object.

The big bang, the singularity, is significant because at the moment that the mass/energy of the universe is in the singular state, it is identical to all the other universes. It is at this point that it "connects" to all the other universes, like petals connecting together to make a flower.

Questions of religion, spirituality and what it means to be human start getting in your way once you start looking at things this way. Am I an aspect of this object that is my universe, or am I some sort of traveler within this object that is a universe?

I think there's a good possibility that the missing matter and forces we hypothesize to be acting upon our universe are actually other universes influencing our own, like petals on a flower bumping into each other. And, assuming that we are "souls traveling within the universe" as opposed to "4 dimensional objects that are aspects of the universe", it isn't outside the bounds of reason to imagine that we might one day be able to map the shape of these universes and achieve "time travel" by moving to other universes.

I expect that we will eventually find the concept of the "infinite universe" to be a false path, and that we will achieve great breakthroughs when we find a framework that doesn't rely upon its existence.

Re:Being special

[mcgrew]

This is no harder than believing in dark matter and dark energy, and it's before breakfast

"Time is an illusion, lunchtime doubly so". -The Hitchhiker's Guide to the Galaxy

Re:Being special

[Artifakt]

We don't necessarily have to be at or near the center of such a bubble, here's the conditions we might require:

1. We would have to somewhere be in a bubble that is much less dense than the actual average for the universe,
2. that bubble would have to be pretty uniformly less dense for the 12 Billion light year radius around us. It doesn't have to be exactly uniform, in fact one reason we might be able to detect it is if it isn't. The bubble doesn't have to be spherical, overall, or uniformly dense, overall, and the nature of the edge, where it becomes more like the rest of the universe is, is allowed some variation as well.
    (In fact, from what the original paper says so far, the center of the bubble could still be even less dense than our part, just so those lower density regions were more than the observable length away.)
    (If this hypothesis develops into a full fledged theory, we would probably be able at a minimum to confirm or reject the existence of even lower density regions, predict how thick the edges of the bubble are, and write an equation that describes how the density would go up, as hypothetically measured at different points in the edge.).
3. The bubble would have to be pretty big, bigger than the time it takes light to cross the entire part of the universe we can see. Since we estimate the universe is about 12 Billion years old, the edges of the bubble must be more than that number of light years away from our POV. But, we don't have to be equally near all edges.
      (We could still possibly see some effects from what is now farther away, because we can observe things such as the cosmic microwave background, that preserve data from the very early times when things were much closer together. We could also see the indirect effects of gravity on things we can see directly in the visible, Gamma or UV ranges).
4. We would have to be near enough to an edge in at least one direction that we could see the effects of those hypothetical average density regions that lie farther than 12 Billion light years away. That way, we may never be able to see them directly, but we can infer them from the parts we can see, so this becomes testable. So if the bubble is much bigger than 24 billion light years across, we must not be too near the center. The bigger the bubble is, the farther out from the center we would have to be to detect something, but that's still a pretty general requirement that we be somewhere in a pretty big volume, not really something improbable or requiring a particularly privledged viewpoint. Our view would be unusual, but not unique.
5. Near enough in point 4 depends on how swiftly the edge of the bubble changes to a more average density, and just what the average is, among other factors. Again, actually coming up with some more specific numbers is what will happen if this hypothesis gets developed into a more established theory. The researchers will calculate some combinations of overall size, rate of change at the edges, and density for the larger universe, and see if there are combinations that predict something we can observe to test them, while throwing out combinations that lead to conclusions contrary to what we can observe. Better yet, a lot of our existing observations can be used to swiftly develop this hypothesis - this is much more testable right now than, say, string theory.

Re:Being special

[f()rK()_Bomb]

The observable universe is actually more like 96billion light years across, its a common mis-conception that because its 13.7 billions years old, its 27billion light years wide. This would b true if space was flat, but on cosmological scales, its highly curved.

The lower bound on the size of the universe, based on the CMBR is 78billion light years, any smaller, and then light would have circumnavigated it since the big bang, and we would see multiple images in the CMBR

http://en.wikipedia.org/wiki/Observable_universe

We known this for a long time

[Iowan41]

At least as far as gas and dust are concerned. The Standard Model explanation is that a 'nearby' star (the pulsar Geminga) went supernova a good long time ago, and blasted a large bubble (300 ly across) of relatively gas and dust free space, called 'the Local Bubble', and our solar system is well within this bubble. The relationship between that and what is being discussed I do not know, for details haven't been provided even on such things as scale. Do a search on 'Local Bubble' and you will find a great deal of information about this.

Re:We known this for a long time

[Anonymous Coward]

This is different bubble. The Local Bubble is rather local (tens of parsecs across) and we can easily see gas outside of it. The bubble in the story could be bigger than the visible Universe (gigaparsecs across) and thus can be fundamentally untestable. Plus, null results (that we can't see outside of this gigantic bubble) make it even more unlikely because over- and underdensities are progressively rarer as they get bigger.

Re:Bubble?

[explosivejared]

Dude, don't worry God will just be there with a 700 quadrillion ton slab of dark matter to bail... I mean patch the hole right up.

Re:Occam's Razor?

[kisrael]

My favorite alternative is that we need someone to do to Einstein what Einstein did to Newton; that just like Newton's laws are near-perfect and beautiful at reasonable speeds, maybe there's something that happens at cosmically grand distances, masses, or propagation delays for Gravity that we're going to have to be awfully clever to ever hope to reliably detect.

Dark Matter and Dark Energy both felt like big hacks to me.

But, I am by no means a scientist, just an interest layman who hasn't done enough reading.

I concur and have the following questions.

[scubamage]

I like this theory. My questions are, if our known universe is a bubble/globule of matter floating in a larger void...

1. Where are the other globules?
2. What happens if we hit one?
3. Where did the globules originate?
4. Is that larger void a super-large globule itself inside a still larger void? If so, see questions 1-4.

Re:You mean like...

[Quietust]

There would definitely be significant time dilation in close proximity to said black holes, but beyond even a fraction of a light year it would become negligible due to the rate at which gravitational force weakens.

Re:The anthropic cop-out

[Anonymous Coward]

It's perfectly reasonable to think that, if sentient life requires unusual circumstances, then we will find ourselves in unusual circumstances.

It's already the case that we're in a rather odd location. Pick a random point in the universe. Does it happen to be on the surface of a planet? Of course not.

Re:The anthropic cop-out

[caramelcarrot]

It's not really a cop out if you can actually give the statistically biasing action. It is a bit of a cop out to just say "specialties make our sentient life possible (or much more probable)" but if you can quantify this, then it would be possible to quantify the experimental bias. The anthropic principle is a lot more rigorous than people give it credit for. Of course rare events are always possible, too.

Dark Matter

[Anonymous Coward]

Capitol Hill region of space. That is one ultra dense region of hot air

Actually, that particular region of the universe consists of dark matter. It's an enormous pile of it, brown in color, steaming and giving off fetid odors that would knock a buzzard off a shit-wagon*. The region is full of it and amazingly, endless numbers of primitive little life-forms actually burrow themselves into it and suck nutrition from it.

* We miss you, George.

Management

[JayAitch]

Always thought it was upper management that lived in a bubble.

Re:Bubble?

[Praedon]

Why does the first thing that comes to mind after reading just this headline, make me think of that one episode on Star Trek Voyager, when Voyager got caught in that planets atmosphere/space-time bubble and time on that planet was accelerating at like almost a week for every second on voyager... and then the civilization finally learned space travel and went up to voyager, and learned about all the time acceleration... Kinda screwed up if this is all true. :P

Re:Occam's Razor?

[philspear]

I thought it was for deciding between two or more competing theories. I didn't think it could be used to reject all theories. If you have two theories, one makes two assumptions, one makes just one, it's more likely to be the one that just makes one. While both may be wrong, you can't use Occam's razor to throw BOTH of them out.

Furthermore, you don't use it at all, or if you did, you forgot to tell us the outcome. You actually just say both sound like deus ex machina, are both silly, and we're not right yet. Didn't even mention any underlying assumptions. That's not Occam's razor, or even rational argumentation. You just have a gut instinct that they're both wrong.

Sparse bubble more special than "normal" matter?

[Keramos]

As mentioned in the article:

One problem with the void idea, though, is that it negates a principle that has reined in astronomy for more than 450 years: namely, that our place in the universe isn't special. ... "This idea that we live in a void would really be a statement that we live in a special place,"

Hold on a second...

Current thinking is that 74 percent of the universe could be made up of this exotic dark energy, with another 21 percent being dark matter, and normal matter comprising the remaining 5 percent.

So, being part of the 5 percent of "normal" matter isn't living in a "special place"?

Obvious Answer

[gbutler69]

It's globules all the way down!

Re:Bubble?

[MightyYar]

Why does the first thing that comes to mind after reading just this headline, make me think of that one episode on Star Trek Voyager

Wow, our minds just totally work differently. I thought of J-Lo's ass.

Re:The anthropic cop-out

[corbettw]

I've always preferred the misanthropic principle, myself. "We see the universe the way we do because people are idiots."

Re:You mean like...

[caramelcarrot]

Considering the point was related to the effects of such a black hole on the outskirts on the galaxy, then yes, the oddities of the gravitational field of the black hole are on a massively smaller scale and totally irrelevant. Your point that the field isn't exactly the same is true, but pedantic and irrelevant to the discussion.

Re:You mean like...

[Goaway]

that would slow down time in the area.

The point is, no, it would not, not to the degree you are thinking of. Look, we do know what a galaxy is! We know there's a lot of mass in there! And it's easy to calculate the time dilation it causes, and it is negligable.

Re:Management Would it SUCK or...

[Hognoxious]

Would it BLOW if someone burst our bubble?

I don't know, but it'll probably cost a lot more than 700 billion dollars to bail the universe out.

Re:The anthropic cop-out

[thasmudyan]

I may be wrong, but isn't the term anthropic principle essentially the opposite of what you're describing? IMHO the anthropic principle just states that there is nothing special about our particular environment beyond the fact that we happen to live here and there is not much else that we have experience with?

Sadly, religious nutjobs have completely turned around what was once an important scientific reasoning tool that existed to make sure our observations of nature are not biased towards human existence.

The anthropic principle is the mother of all cause-and-effect observations. The obvious cause here is that we live in a certain environment with a certain set of rules and random environmental factors, as a consequence of this, we have turned out the way we are now - including our way of interpreting the world around us. Now religious people, for whatever fucked-up reason, believe our environment was actually created by someone just for us to live in, and that the purpose of our universe is to support human life - thereby turning common sense on its head by confusing cause and effect.

The alleged cop-out that is Wikipedia

[tepples]

To make even more of an impact, though, try linking to a reputable source.

By linking to a Wikipedia article, I linked to all the reliable sources that the Wikipedia article cited. Do you complain that they are not reliable sources, or do you claim that the Wikipedia article misrepresents the sources?

Re:Bubble?

[Xonstantine]

Why does the first thing that comes to mind after reading just this headline, make me think of that one episode on Star Trek Voyager

Because you are a nerd.