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Cosmic Noise

Universe Could be 250 Times Bigger Than What is Observable

Article Updated: 24 Dec , 2015

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Our Universe is an enormous place; that’s no secret. What is up for discussion, however, is just how enormous it is. And new research suggests it’s a whopper – over 250 times the size of our observable universe.

Currently, cosmologists believe the Universe takes one of three possible shapes:

1) It is flat, like a Euclidean plane, and spatially infinite.
2) It is open, or curved like a saddle, and spatially infinite.
3) It is closed, or curved like a sphere, and spatially finite.

While most current data favors a flat universe, cosmologists have yet to come to a consensus. In a paper recently submitted to Arxiv, UK scientists Mihran Vardanyan, Roberto Trotta and Joseph Silk present their fix: a mathematical version of Occam’s Razor called Bayesian model averaging. The principle of Occam’s Razor states that the simplest explanation is usually the correct one. In this case, a flat universe represents a simpler geometry than a curved universe. Bayesian averaging takes this consideration into account and averages the data accordingly. Unsurprisingly, the team’s results show that the data best fits a flat, infinite universe.

But what if the Universe turns out to be closed, and thus has a finite size after all? Cosmologists often refer to the Hubble volume – a volume of space that is similar to our visible Universe. Light from any object outside of the Hubble volume will never reach us because the space between us and it is expanding too quickly. According to the team’s analysis, a closed universe would encompass at least 251 Hubble volumes.

That’s quite a bit larger than you might think. Primordial light from just after the birth of the Universe started traveling across the cosmos about 13.75 billion years ago. Since special relativity states that nothing can move faster than a photon, many people misinterpret this to mean that the observable Universe must be 13.75 billion light years across. In fact, it is much larger. Not only has space been expanding since the big bang, but the rate of expansion has been steadily increasing due to the influence of dark energy. Since special relativity doesn’t factor in the expansion of space itself, cosmologists estimate that the oldest photons have travelled a distance of 45 billion light years since the big bang. That means that our observable Universe is on the order of 90 billion light years wide.

To top it all off, it turns out that the team’s size limit of 251 Hubble volumes is a conservative estimate, based on a geometric model that includes inflation. If astronomers were to instead base the size of the Universe solely on the age and distribution of the objects they observe today, they would find that a closed universe encompasses at least 398 Hubble volumes. That’s nearly 400 times the size of everything we can ever hope to see in the Universe!

Given the reality of our current capabilities for observation, to us even a finite universe appears to go on forever.

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sukhoi4700
Member
sukhoi4700
February 8, 2011 9:01 AM

I hope someday we find a way past special relativity and travel far across

Olaf
Member
Olaf
February 8, 2011 9:57 AM

One moment.
Light travelled for 13.75 billion years and I think it travelled 13.75 billion light-years too.
So how can it have travelled 45 billion light-years?

I do agree that the point that the photon originated moved away during that 13.75 billion years but the photon itself did not travel more than 13.75 billion light-years.

brasey
Member
February 8, 2011 10:13 AM

If your reference point is the starting point of the photon, and you stretch out 13.75 billion light years of measuring tape, you don’t get the current location of the photon. You have to stretch the measuring tape too, due to expansion. So the actual distance traveled is longer. The odometer on the photon thinks it travelled 13.75 billion light years, though.

If we’re moving away from that photon, the actual distance is even farther.

At least that’s how I think this works.

Vanessa D'Amico
Guest
February 8, 2011 10:16 AM

brasey’s got it right. Something that’s important to remember is that the space through which the photon is traveling is always expanding. Imagine it’s a hot day at the beach and you’re running toward the water (which is, say, 10 meters away), but suddenly the ground under your feet starts rapidly expanding – not just away from you, but in every direction. By the time you actually reach the water, you’ve been running for a very, very long time. Depending on how quickly the ground was expanding, you may have run tens of kilometers instead of just a few meters – even if you were running at a set speed.

renoor
Member
renoor
February 9, 2011 12:53 AM

Vanessa, i don’t agree. Let’s say the sea is 10 meters away. I put a stick into the ground and start walking. As the ground under my feet is expanding, I have to make 50 steps, each 1 meter long, until I reach the sea. I will be convinced that I’ve walked 50 meters, even if my “point of origin” is 100 meters away when I turn back and measure the distance to the stick in the ground.

Vanessa D'Amico
Guest
February 9, 2011 5:40 PM

Yes, that’s true. The space behind you will have expanded, leaving your point of origin further away than you may have travelled. However, the space in front of you is expanding too, and so you have to walk further than you would have if the ground was stationary. The important point is that the expansion of the universe occurs everywhere, at every point. Not just in one direction – “away.” Like you said, you may have only travelled 50 meters, but you certainly didn’t travel 10.

Split_Infinity
Member
Split_Infinity
February 9, 2011 12:59 AM

Where does all this extra space come from, even nothing still is something due to vacuum energy I read.

hal9000
Member
hal9000
February 8, 2011 10:31 AM
The big bang theory just drives me nuts. May the universe be 13, 50 or 10000 billion years old doesn’t change it. Look at the keyboard in front of you, your cup of coffee, the trees outside, the earth, the solar system, our galaxy, all the galaxies we can spot and tell me this is the result of a big explosion in which everything we can imagine was contained into? What was the size of this “explosive ball”? Infinitely small? I hate the “infinite” concept too. And if before the big bang, this massive ball did exist, wasn’t there another container for it? Or maybe the universe is the container and the content at the same time :s… Read more »
DrFlimmer
Member
DrFlimmer
February 8, 2011 11:32 AM
Yeah, physics is not made to be imaginable. Either it is too big and we can’t imagine it, or it is too small and we can’t imagine it and its weired effects, either. Btw: It is meaningless to ask “what is outside of our universe”, or is our universe in something bigger. We cannot find answers to these questions, since we can’t leave “our” universe. And regarding the “singularity”: This will be overcome by quantum mechanics. On very small scales the question for location or even time breaks down. It doesn’t make sense “down there”. However, we will need a theory of quantum gravity to overcome singularities of both the Big Bang and Black Holes. But I’m hopeful… Read more »
Split_Infinity
Member
Split_Infinity
February 9, 2011 1:02 AM

If stars themselves collapse in on themselves due to mass how is it that the original condensed matter did not just do the same, let alone expand, it’s like the opposite of how things are known to work is what is proposed.

cosmo
Member
cosmo
February 8, 2011 1:06 PM
The fact that one or another idea “drives you nuts” is poor reason to discount it. A lot of ideas that have proven true and important, did at one time, drive lots of folks nuts. It is in the nature of inquiry in general to find that things often turn out not to be what one expects. At one point the idea that living things too small to see could be responsible for some illnesses was revolutionary and frequently seen as perposterous. Galileo’s new take on the universe got him in great trouble since his view was at odds with the conventional doctrine of the day. Pretty much every new (and eventually successful) idea, in pretty much every… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 8, 2011 2:32 PM
Maybe you should first try to understand what you try to criticize? What you describe isn’t a big bang cosmology. the result of a big explosion There was no explosion. Big bang follows from observing that our current universe is expanding. Going back in time we realize that the initial state was more compressed and so hotter. But the universe is expanding in every point (volume), so moving back contracting in every point (volume). That is not an explosion, which must have a center. Universal expansion # “explosion”. in which everything we can imagine was contained into And this isn’t our standard big bang cosmology. Inflation inverts the picture. Here is what theoretical astrophysicist Ethan Siegel says on… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 8, 2011 3:10 PM
I hate the “infinite” concept too. That is a whole other bag of physics. You could understand standard cosmology as finite, bounded, properties if you will. There are IMO a few, possibly related threads weaving into the “infinite” physics picture. First, if you look from the viewpoint of theory, it is simpler to use infinities. Testing of theories will in some cases naturally result in infinities being “best of breed”, as here. Second, if you look from the viewpoint of physics, nature is algorithmic since physics theory is. (Or theory wouldn’t work.) You can use infinites in algorithms, say cancellation by infinities, so nature can too. Third, if you look from the viewpoint of reality, the only sound… Read more »
DrFlimmer
Member
DrFlimmer
February 9, 2011 2:18 AM
Well, I see String Theory also as a theory of “quantum gravity”. It aims to combine GR and quantum mechanics, does it not? However, my statement was not directed at any specific version of a “quantum gravity” (may that be String Theory or Loop Quantum Gravity), I used it merely as a place holder for a unified theory, which we still lack and need (as I assume you’ll agree). I for myself watch the big fight “String Theory” versus “Loop QG” with some amusement. My knowledge of mathematics is far too low to be able to grasp any of both in all its details, so my knowledge of both is quite rudimentary. I’ll wait and see, what will,… Read more »
brogue
Member
brogue
February 8, 2011 3:28 PM
Big Bang Theory is almost always poorly presented. The initial size of the “ball” is important but no one defines terms well enough to know the size for sure. Thus most accounts misrepresent it by calling it very small or “infinitely small”. This is bogus. IF the Universe is infinitely large now then it was infinitely large at the beginning. Our little Hubble Bubble is finite and it may have been very small before it inflated. This is true, but the Hubble Bubble is not the whole Universe. We have no reason to assume the Universe was ever anything but infinite even 14.5 billion years ago when it was much denser. Back then it was very dense and… Read more »
Deon
Member
Deon
February 8, 2011 9:16 PM
The Eclectic Exterminator of Stupid Electricians
Member
The Eclectic Exterminator of Stupid Electricians
February 11, 2011 2:50 PM

For everyone else, don’t bother….

henk
Member
henk
February 8, 2011 10:51 AM

but if the oldest protons travelled a distance of 45 billion years . How do we now that the universe is 13.75 billion years old. Why is it not 30 billion, because how do we now how old that light is if the expansion allow that the protons move faster ?

DrFlimmer
Member
DrFlimmer
February 8, 2011 11:26 AM

First of all it’s a photon that traveled that distance, not a proton (which is a quite massive particle).

And second, the photon didn’t move faster. It’s just that its starting point (where it comes from) has also moved away from us, so that it is now 45billion light-years away. The photon traveled 13.7 light-years, but the expansion of the universe has moved this origin farther away from us.

And how do we know, how old the universe is? Well, for example, the temperature of the cosmic microwave background is consistent with a universe that is at that age. And there are other measurements as well.

postman1
Member
postman1
February 8, 2011 2:04 PM

One question- If the starting point moved to 45 billion light years from us while the photon moved 13.7 ly and reached our observers, Would that mean that the starting point moved at least three times the speed of light? Also, if they are speeding up exponentially, would that mean that their present speed is even many times faster? Or, is it that the space between is expanding, but the starting point is not necessarily moving at all?

Astrofiend
Member
Astrofiend
February 8, 2011 2:26 PM

“Or, is it that the space between is expanding, but the starting point is not necessarily moving at all?”

Yep – the speed of light limit only applies to THINGS moving through spacetime. Two arbitrary POINTS in spacetime can move away from each other at any speed at all. So when we say things like ‘galaxies are receding from us’, they aren’t flying backwards through space away from us, rather they are ‘flowing along’ with space as all of space expands.

Olaf
Member
Olaf
February 9, 2011 10:54 AM

In other words: Space itself is not limited to the speed of light and can move much faster. Of course if space expands faster than the speed light no photon will ever reach another star ever.
Is that not what is happening inside a black hole? Space travelling faster than the speed of light?

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 8, 2011 2:13 PM
Now this is still modeling from data. The simplest theory that we can test is flat and infinite. What is encouraging is that better modeling supports the best theory. Also, it must drive the naiveté “there are no multiverses because we can only ever see the visible universe” crowd nuts that we know that our own universe (and science) is bigger than that! Bayesian averaging takes this consideration into account and averages the data accordingly. Unsurprisingly, the team’s results show that the data best fits a flat, infinite universe. This may be a bit confusing. AFAIU bayesian modeling in general (and this paper in particular, it shows which models that best fits the data. That was how standard… Read more »
Astrofiend
Member
Astrofiend
February 8, 2011 2:40 PM
I’m no wizz with Bayesian methods, and I haven’t read they’re paper yet, but I have looked at Bayesian stuff a bit. Bayesian stats basically says that given some prior knowledge of how a system must be, how likely is it that we obtain the observational data that we get. Or – assuming a model, what is the relative probability that the data comes about as a result of the modeled physics or by chance alone? This is different to normal parameter fitting, which says give me the data and I’ll find a model that works for you. So in this case, I’d assume that they’ve looked at it and said OK – If we assume a flat… Read more »
Uncle Fred
Member
Uncle Fred
February 8, 2011 4:23 PM

I think what’s needed is a few articles from the team on Cosmology basics.

Lately, there has been a lot of repeated questions on some of the more difficult topics to grasp. We need an article on the origin of the universe, explained in Cosmology 101 terms for the non-initiated. Some video visuals explaining the big bang, the expansion of the universe etc would be helpful.

UF

Astronomy 101

riverlaw
Member
riverlaw
February 8, 2011 5:09 PM

there are really good pod cast out there if these people really wanted to learn the basics. Like i don’t know… astronomy cast!!!

Lawrence B. Crowell
Member
Lawrence B. Crowell
February 8, 2011 5:13 PM
I recommend that people look at: http://www.astro.ucla.edu/~wright/cosmolog.htm Ned Wright gives a reasonable account on the ABC’s of cosmology. It is preferrable to my spending more of the beaucoup time already spent trying to explain these things. I will say this; the universe is larger in distance than in light years because of the dynamics of space. Space itself is expanding, like a rubber sheet that keeps expanding outwards. The speed of light is a local result, it pertains to the speed of light in a flat spacetime or a small region where any curvature is insignificant. On a larger scale spacetime may be curved, which adjusts the local law. For example the event horizon is a membrane where… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 9, 2011 6:52 AM

Good idea on the basics/ABC.

Sure, I get the principle of the UV/IR correspondence. I am not sure if there is anything in the actual details that prohibits infinite (large, energetic) states. String theory takes care of some singularities naturally, for example associated with particles and their interactions, but I don’t think there is any singularity involved with infinities as such. (The reverse applies of course, mathematical singularities takes any value (except maybe one), so infinities will happen around them.)

Lawrence B. Crowell
Member
Lawrence B. Crowell
February 10, 2011 5:40 PM
Getting into this in detail is a bit much for a UT post, particularly one which is heading off the horizon. The black hole has metric correspondence with the D5-brane, or the brane in the NS-NS sector is called the NS5-brane. This is has dualities with the M2-brane and the D3-brane. The M2-brane is curious and is a two dimensional region which holds open strings with properties similar to graphene. The dynamics is governed by the Chern-Simons Lagrangian. This adds an action to the gravitational action which might act as a topological cut-off in the eigenstates of gravity. The pure gravitational Lagrangian is not bounded below, but this might serve as a topological correction. So the black hole… Read more »
Deon
Member
Deon
February 8, 2011 9:08 PM

http://www.physicsmyths.org.uk/cosmology.htm
The Big Bang Theory
A Flawed Concept

Olaf
Member
Olaf
February 9, 2011 10:55 AM

Ohhh boy, another PC/EU SPAM.

The Eclectic Exterminator of Stupid Electricians
Member
The Eclectic Exterminator of Stupid Electricians
February 10, 2011 8:26 PM

Deon’s Big Bang Theory
A Flawed Concept
Enough said…

zimknuj
Member
zimknuj
February 8, 2011 11:18 PM
“Cosmologists often refer to the Hubble volume – a volume of space that is similar to our visible Universe. Light from any object outside of the Hubble volume will never reach us because the space between us and it is expanding too quickly.” Careful, the Hubble radius is *not* the size of the visible universe or even close. The Hubble radius defines the distance to where an object at rest in the expanding universe is receding at the speed of light. An object further away is receding even faster (remember, general not special relativity). But that doesn’t mean it’s light will never reach us (or has not already). A photon emitted from an object beyond the Hubble radius,… Read more »
zimknuj
Member
zimknuj
February 8, 2011 11:55 PM

Sorry, meant an event horizon, not a particle horizon, which is something else.

deshan
Member
deshan
February 9, 2011 4:05 AM

Truly believe universe is infinity Times Bigger Than What is Observable.

Lawrence B. Crowell
Member
Lawrence B. Crowell
February 9, 2011 5:39 AM
I second Zimknuj’s assessment of the cosmological horizon. The Friedmann-Lematre-Robertson-Walker (FLRW) metric gives the energy equation for the scale factor a (a’/a)^2 = (8 pi GM/3)rho (a’ = da/dt) where rho is the density of mass-energy which determines the spacetme dynamics. If this is constant, and equal to the de Sitter constant /\, the equation of motion is a’ = sqrt{(8 pi GM/3)/\}a and the equation of motion involves the exponential growth in the scale factor with time. The Hubble relationship is v = Hd, d = distance out, v = velocity, and H = (a’/a) the Hubble constant (constant in space but not in time). This is an approximate relationship, where clearly the scale factor exponentially grows… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 9, 2011 6:58 AM

I haven’t seen it done, but I believe it would be possible to make an analogy like the “photon in a stream” which may be used for black holes to explain the event horizon (and especially how it is a global and not a local observable phenomena). However, I can resists writing long posts at times, so I will stop there… grin

spameroo
Member
spameroo
February 9, 2011 9:58 AM
As I understand it, our whole universe was in a hot, dense state, then almost 14 billion years ago, expansion started… wait… Anyway, I think it’s really important to remember that a lot of this speculation involves hypotheses that can not and will not ever be testable. There might be logical, reasonable extrapolations we can make, but in the end, a paper about properties of the extra-Hubble universe has equal claim to call itself “science” as a paper discussing how Genesis 1:1-3 proves that “dark energy” is actually God’s power, expanding the universe. That is to say, it’s fun to think about, and you might even be able to come up with some plausible ideas – hell, you… Read more »
StarzDust
Member
StarzDust
February 10, 2011 10:05 AM
spameroo, I like your terminology! There is a lot of conjecture in any perhaps all cosmological hypotheses. I kinda am amused by string theory. It seems to me although plausible, we may never be able to test it’s validity in the real cosmos. I mean, it appears to me to be too complicated and unfalsifiable because there is, at present, no way to test it. At the very essence nature may have a simpler explanation. Some replies dance around Occams Razor; that within several plausible explanations for a particular hypothesis, the simpler explanation is usually the correct one. For me, I’ve been particularly attracted to the “brains” idea, where our universe is the result of two different membranes… Read more »
StarzDust
Member
StarzDust
February 10, 2011 10:09 AM

Oops,

I meant to type Celsius instead of “centimetre” My brain works too fast and I can’t keep typing up to the same speed.

StarzDust

The Eclectic Exterminator of Stupid Electricians
Member
The Eclectic Exterminator of Stupid Electricians
February 10, 2011 8:22 PM

“dark energy” is actually God’s power.

Yeah. It is probably the exact same power as those “astrological energies” used for astrology predictions. I suppose that is just as plausible too?

Dan Echegoyen
Member
February 9, 2011 4:10 PM
BLACK HOLES, EXPANSION, AND DARK ENERGY In the continuum of space and time, exists the dichotomy of matter and energy. All things exist as both matter and energy, but are experienced as one or the other. As energy, all things exist as wave patterns. Most wave patterns are interferences of simpler wave patterns. The simplest wave forms are those that do not interfere with other waves. These simplest wave forms hold their shape as they propagate. There are three such wave forms. The first such wave form is seen in three dimensions as the spherical expansion wave of a bomb blast, and in two dimensions as the circular wave of expansion on the water where a rock was… Read more »
Astrofiend
Member
Astrofiend
February 10, 2011 5:03 AM

Woah dude – that was like, a trip man. Pass the bong…

The Eclectic Exterminator of Stupid Electricians
Member
The Eclectic Exterminator of Stupid Electricians
February 10, 2011 8:18 PM

Actually, this post is easy to correct.
The word is “No.”
Enough said.

dbob
Member
dbob
February 9, 2011 3:57 PM

Here’s a neet chicken and egg conundrum. If this whole thing (our cosmos) started out as a cosmologically sized singularity, you would have needed an outside gravity force (or something like it) to hold it all together, at least long enough for it to lose it’s symmetry for whatever reason, and come undone. That is unless it is sufficient to have the gravity force holding it together strictly on the inside of the singularity. If it is outside, then we have a pre “Big Bang” condition. On a side note, “Infinity” is the logical condition for reality, otherwise you would have need of a “creator” and that would move the discussion into the realm of metaphysics.

Question
Member
Question
February 9, 2011 7:30 PM

good spirited discussion in this thread people. it really sparks the imagination.

The Eclectic Exterminator of Stupid Electricians
Member
The Eclectic Exterminator of Stupid Electricians
February 10, 2011 8:12 PM

Nothing beats looking like looking like the good guy when you, in fact, already part of the real problem of anti-science or pseudoscience.

Astronomy and astrophysics is based on real facts, observation and sensible deduction that can be again tested. The only “imagination” is coming up with new clever ways to make observation to confirm current theory. It is not coming up with wild speculation just because someone think it is right or is based on some agenda. Your deceptions and foolishness here is clear for all to see.

apinakapina
Member
apinakapina
February 9, 2011 11:30 PM

Well, in order to make those calculations, wouldn’t it to be necessary to know our location in the universe? I don’t think anyone has have a clue where we are, on the edge or in the near centre. What we observe, is nothing near what there is. It applies to all sciences, people always assumes we know more than we don’t.

And the age of the unverse, could it be possible that the primordian lightsource just died out 13.75 billion years ago? grin No one knows how exatly the cosmos/universe came to be, so how can one assume anything by just the age of the radiation?

Astrofiend
Member
Astrofiend
February 10, 2011 5:00 AM
“No one knows how exatly the cosmos/universe came to be, so how can one assume anything by just the age of the radiation?” Well, we DO have a pretty good idea of how the universe came to be. It was the Big Bang model that made the concrete prediction of the existence of the Cosmic Microwave Background and its detailed properties, which was subsequently discovered and it’s properties verified. The fact that we have several independent lines of evidence supporting the theory, coupled with the fact that the physics is well understood even back to just after the BB gives us a fair degree of confidence that we are on pretty much the right track. We’re not assuming… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
February 10, 2011 10:31 AM
I posted Ned Wright’s cosmology page the other day, and once again: http://www.astro.ucla.edu/~wright/cosmolog.htm I strongly advise people to read the real stuff. If you want to have some clear idea about these matters please do this. Looking at “alt-sci-blogs” or running away with your own ideas which are not well substantiated is not very likely to get you anywhere. The basic big bang model is very well substantiated. From the Hubble relationship on galaxy red shifting, to the D-He abundance in the universe, the CMB, and even the number of quark doublets in the universe, the basic big bang concept is observationally well tested. Inflation is less well grounded, but the anisotropy CMB results and the end of… Read more »
dbob
Member
dbob
February 11, 2011 9:16 AM
LC…. thanks for the tip on Wrights web page. Good stuff. There is a whole world out there. Thank god (non-literal) for the internet. He (Wright) has a link to Sean Carroll’s web page… Carroll postulates (hopefully I’m not misreading his intent) some kind of attractive force in the precursor state pryer to the Big Bang, (god I hate that term, wish there were a better descriptive) as possibly quantum gravity. Now postulating that the “Big Bang” and what we can view and test, is only a part of a larger process, then we should be able to tease out at least a logical set of events, perhaps provable, leading back to “before” the event itself. Since the… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
February 11, 2011 1:28 PM

This gets into matters of inflation, so called eternal inflation, and spacetimes as emergent on D3-branes in M-theory. If a topic comes up which warrants a post on those matters I might write one up.

LC

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