## Universe Could be 250 Times Bigger Than What is Observable

by Vanessa Janek[/caption]

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.

closed, Cosmology, expansion, flat, geometry, open, universe

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

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.

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.

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.

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.

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.

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

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.

http://www.physicsmyths.org.uk/cosmology.htm

pleas see this web site

For everyone else, don’t bother….

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 ?

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.

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?

“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.

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?

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

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

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.)

http://www.physicsmyths.org.uk/cosmology.htm

The Big Bang Theory

A Flawed Concept

Ohhh boy, another PC/EU SPAM.

Deon’s Big Bang Theory

A Flawed Concept

Enough said…

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

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

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…

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

“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?

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

Actually, this post is easy to correct.

The word is “No.”

Enough said.

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.

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

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.

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? No one knows how exatly the cosmos/universe came to be, so how can one assume anything by just the age of the radiation?

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